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Does compass app need magnetometer?

I need a compass app and the Play store has loads, but about half of
them say that the phone has to have a magnetometer, and from gsmarena,
it seems my Blu phone Android v.5 does not 
  ( http://www.gsmarena.com/blu_studio_x_plus-6926.php )

Some of them have in big print that a magnetometer is needed and others
say nothing.   One of them that seemed really good finally said 21 lines
in "Large iron and steel objects can influence the magnetic sensor in
your Android device, "
https://play.google.com/store/apps/details?id=com.gamma.compass

So, do some not require a magnetometer?   

If they don't require one, do they require nearby cell towers?    Some
of my driving won't be in cell tower range.   At least the coverage map
doesn't show coverage. 

Is there some 3rd or 4th way that a compass app can figure out
direction?  (Are the answers to this the same as to "What is needed for
GPS to figure out location?") 


I could just install some and go out to where  there is no cell coverage
and see if they work, except that when I signed up 7 or 10 years ago
there were areas like that for AT&T only 20 minutes away.  Now their
coverage map shows only small areas 2 hours from here, and the areas are
in the mountains and so small I don't think I can find them, especially
on foot, which I would have to be.   

TIA
0
micky
12/18/2016 6:18:34 AM
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On 12/17/2016 10:18 PM, micky wrote:
> I need a compass app and the Play store has loads, but about half of
> them say that the phone has to have a magnetometer, and from gsmarena,
> it seems my Blu phone Android v.5 does not
>    ( http://www.gsmarena.com/blu_studio_x_plus-6926.php )
>
> Some of them have in big print that a magnetometer is needed and others
> say nothing.   One of them that seemed really good finally said 21 lines
> in "Large iron and steel objects can influence the magnetic sensor in
> your Android device, "
> https://play.google.com/store/apps/details?id=com.gamma.compass
>
> So, do some not require a magnetometer?
>
> If they don't require one, do they require nearby cell towers?    Some
> of my driving won't be in cell tower range.   At least the coverage map
> doesn't show coverage.
>
> Is there some 3rd or 4th way that a compass app can figure out
> direction?  (Are the answers to this the same as to "What is needed for
> GPS to figure out location?")
>
>
> I could just install some and go out to where  there is no cell coverage
> and see if they work, except that when I signed up 7 or 10 years ago
> there were areas like that for AT&T only 20 minutes away.  Now their
> coverage map shows only small areas 2 hours from here, and the areas are
> in the mountains and so small I don't think I can find them, especially
> on foot, which I would have to be.
>
> TIA
>

How about using a magnet to see if it affects the direction?
If you don't move, there ain't no way for data to determine your direction,
but a magnet will influence direction based on magnetic info.
0
mike
12/18/2016 7:31:16 AM
Dne 18/12/2016 v 07:18 micky napsal(a):
> I need a compass app and the Play store has loads, but about half of
> them say that the phone has to have a magnetometer, and from gsmarena,
> it seems my Blu phone Android v.5 does not 
>   ( http://www.gsmarena.com/blu_studio_x_plus-6926.php )
> 
> Some of them have in big print that a magnetometer is needed and others
> say nothing.   One of them that seemed really good finally said 21 lines
> in "Large iron and steel objects can influence the magnetic sensor in
> your Android device, "
> https://play.google.com/store/apps/details?id=com.gamma.compass
> 
> So, do some not require a magnetometer?   
> 
> If they don't require one, do they require nearby cell towers?    Some
> of my driving won't be in cell tower range.   At least the coverage map
> doesn't show coverage. 
> 
> Is there some 3rd or 4th way that a compass app can figure out
> direction?  (Are the answers to this the same as to "What is needed for
> GPS to figure out location?") 
> 
Well, compass application does need magnetometer to act as compass,
like a classical compass does need the magnetic component.
This need is explicit or implicit.

The point is, there are other ways to determine direction,
as there are other ways to determine position.
But the device must have ability to use alternative ways.

For position, the cell towers of WiFi can be used,
instead of GPS. This is usually managed on systemm level.

For orientation, it is more tricky,
and there is rarely a system support for that,

Frequently used alternative, common for GPS navigations,
it to derive orientation from the course of driving
as the time change of position. E.g. if last but one position
was 20 metres to south wrt the current one, it realizes
you are heading to the north.

Cell towers cannot be used for orientation.

Theoreticallly the rotational accelerometers could be used
to determine orientation, but there is a big problem with a drift.

-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.
0
Poutnik
12/18/2016 7:32:06 AM
micky <NONONOmisc07@bigfoot.com> wrote:

> I need a compass app and the Play store has loads, but about half of
> them say that the phone has to have a magnetometer, and from gsmarena,
> it seems my Blu phone Android v.5 does not 
>   ( http://www.gsmarena.com/blu_studio_x_plus-6926.php )

https://en.wikipedia.org/wiki/Compass#Solid_state_compasses

Somehow I can't see anyone relying on a compass app in their smartphone
as substitute for a real compass when hiking, boating, or anywhere in
the wild.  Go buy one.  Some are very cheap ($4 at Walmart,
https://www.walmart.com/ip/Ultimate-Survival-Technologies-Lensatic-Compass/34609100).

Even a little cheap one that snaps onto a coat's zipper tang ($3,
https://www.walmart.com/ip/Coghlans-8268-Pin-On-Compass-Ball/26957099)
would be a better investment.  A real compass doesn't stop working
because a battery went low or dead, and a real compass isn't susceptible
to extremes in temperatures, especially cold, as would a battery in a
smartphone.  A real one doesn't make you enter a lockscreen code.  And a
real compass doesn't make you wait to turn it on, load and OS, and then
load an app.  If you need it lit in the dark, well, you have your, um,
trusty smartphone with its camera light, right?  Or you could get a
small real compass that has a light but remember to regularly replace
the batteries or carry a spare one just like you should be doing for the
smartphone via another battery or a power pack ($6 at Walmart,
https://www.walmart.com/ip/Coleman-Compass-with-LED-Light/29068511).
Try laying a smartphone on a map to chart your route.  Just atop of what
on the map is the center of the magno sensors in the smartphone so you
know from or to where you are charting?

As a survival tool, I'd rather get a real compass (and a good one) than
rely on some app in a smartphone.
0
VanguardLH
12/18/2016 7:52:36 AM
In comp.mobile.android, on Sun, 18 Dec 2016 01:52:36 -0600, VanguardLH
<V@nguard.LH> wrote:

>micky <NONONOmisc07@bigfoot.com> wrote:
>
>> I need a compass app and the Play store has loads, but about half of
>> them say that the phone has to have a magnetometer, and from gsmarena,
>> it seems my Blu phone Android v.5 does not 
>>   ( http://www.gsmarena.com/blu_studio_x_plus-6926.php )
>
>https://en.wikipedia.org/wiki/Compass#Solid_state_compasses
>
>Somehow I can't see anyone relying on a compass app in their smartphone
>as substitute for a real compass when hiking, boating, or anywhere in
>the wild.  Go buy one.  Some are very cheap ($4 at Walmart,
>https://www.walmart.com/ip/Ultimate-Survival-Technologies-Lensatic-Compass/34609100).

I have a real compass**, and that's what I was planning to use, but I
won't be hiking, I'll be driving, and I think I'd have to stop the car
and get out every time I want to check direction.   So I"m still going
to take the real compass, but I want to get a compass app for the phone
too. 

** I have one I bought, plus I have one that one wears on his wrist that
I found in the desk drawer when I was about 10 years old.  I finally
wore out the faded olive drab band and got a new band.  I'm not sure
which I'm going to take. 

>Even a little cheap one that snaps onto a coat's zipper tang ($3,
>https://www.walmart.com/ip/Coghlans-8268-Pin-On-Compass-Ball/26957099)
>would be a better investment.  A real compass doesn't stop working
>because a battery went low or dead, and a real compass isn't susceptible
>to extremes in temperatures, especially cold, as would a battery in a
>smartphone.  A real one doesn't make you enter a lockscreen code.  And a
>real compass doesn't make you wait to turn it on, load and OS, and then
>load an app.  If you need it lit in the dark, well, you have your, um,
>trusty smartphone with its camera light, right?  Or you could get a
>small real compass that has a light but remember to regularly replace
>the batteries or carry a spare one just like you should be doing for the
>smartphone via another battery or a power pack ($6 at Walmart,
>https://www.walmart.com/ip/Coleman-Compass-with-LED-Light/29068511).
>Try laying a smartphone on a map to chart your route.  Just atop of what
>on the map is the center of the magno sensors in the smartphone so you
>know from or to where you are charting?

That's all true.   But I still want an app, especially when it's raining
or I don't want to stop the car to get out. 

>As a survival tool, I'd rather get a real compass (and a good one) than
>rely on some app in a smartphone.


0
micky
12/18/2016 8:03:46 AM
Dne 18/12/2016 v 08:52 VanguardLH napsal(a):

> 
> https://en.wikipedia.org/wiki/Compass#Solid_state_compasses
> 
> Somehow I can't see anyone relying on a compass app in their smartphone
> as substitute for a real compass when hiking, boating, or anywhere in
> the wild.  Go buy one.  Some are very cheap ($4 at Walmart,
> https://www.walmart.com/ip/Ultimate-Survival-Technologies-Lensatic-Compass/34609100).
> 
> [...]
> 
> As a survival tool, I'd rather get a real compass (and a good one) than
> rely on some app in a smartphone.
> 

I fully agree with you in serious outdoor and survival context.

But the OP may have meant it rather as an added value
for a device powered by the car battery.
For a car at usual conditions and GPS aware device,
classical or Solid state compass may not be as essential,
as the course can be easily determined from the GPS itself.

In context of GPS aware map and navigation applications,
the orientation based on the device compass is often used
for low speed movement like geocaching or easy walking,
when course is hard to tell from GPS itself.

Typical use is in LocusMap application,
where the course may be determined
from GPS above threshold speed,
from compas below it.

-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.
0
Poutnik
12/18/2016 8:45:41 AM
Dne 18/12/2016 v 09:03 micky napsal(a):

> That's all true.   But I still want an app, especially when it's raining
> or I don't want to stop the car to get out. 
> 
I would really recommend the LocusMap application.
https://play.google.com/store/apps/details?id=menion.android.locus
https://play.google.com/store/apps/details?id=menion.android.locus.pro

Free one with ads, paid one ads free with some extra features.

It has, aside of many feature useful for outdoor,
also an explicit compass screen, where can be used
direction based both on compass ( if available )
or on GPS ( less accurate for walks, but enough for cars )

( Picture of compass screen on the bottom )
http://docs.locusmap.eu/doku.php?id=manual:user_guide:tools:gps

See also http://www.locusmap.eu/

-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.
0
Poutnik
12/18/2016 8:58:19 AM
On 18/12/2016 08:03, micky wrote:
[]
> That's all true.   But I still want an app, especially when it's raining
> or I don't want to stop the car to get out.

Don't forget that the metallic components in the car may affect the 
compass reading too.  Why not something like this - no need even to get 
the phone out:

 
https://www.amazon.co.uk/s/ref=nb_sb_ss_c_2_17?url=search-alias%3Dautomotive&field-keywords=dashboard+compass&sprefix=dashboard+compass%2Caps%2C176&crid=1P46LYOG00VTN

I have this program:

   https://play.google.com/store/apps/details?id=com.compasspro&hl=en_GB

but from experience it needs calibrating every time before use.

-- 
Cheers,
David
Web: http://www.satsignal.eu
0
David
12/18/2016 9:26:24 AM
On 2016-12-18 09:03, micky wrote:

> 
> That's all true.   But I still want an app, especially when it's raining
> or I don't want to stop the car to get out. 

you also need to go out for the app to work. The magnetometers are
affected by the car body just the same.

This is different from GPS map gadgets: they indicate the direction from
your movement, calculating from your past positions.


Yes, a compass app needs a magnetometer, and they are usually not very
accurate. I see up to 20 degrees errors in mine, in any direction.


-- 
Cheers,
       Carlos E.R.
0
Carlos
12/18/2016 10:58:12 AM
micky <NONONOmisc07@bigfoot.com> wrote:

> I have a real compass**, and that's what I was planning to use, but I
> won't be hiking, I'll be driving, and I think I'd have to stop the car
> and get out every time I want to check direction.   So I"m still going
> to take the real compass, but I want to get a compass app for the phone
> too. 
> 
> ** I have one I bought, plus I have one that one wears on his wrist that
> I found in the desk drawer when I was about 10 years old.  I finally
> wore out the faded olive drab band and got a new band.  I'm not sure
> which I'm going to take. 
> 
> I still want an app, especially when it's raining or I don't want to
> stop the car to get out. 

Why do you have to get out of the car to use a real compass?  If true,
why don't you have to get out of the same car to use an app on a
smartphone using its magnetic sensors?  Magnetic compasses work inside
of cars.  You can even buy ones to mount inside your car (although they
are very rudimentary).  Some rearview mirrors have them.  I'm presuming
there are glass windows in your car and the dash isn't made of metal.

Your smartphone doesn't have GPS?  

Are you taking maps, especially those that show magnetic deviation or
anomalies?  A compass without a map is only useful to get back to where
you started or keep you on a path already known or planned.  You didn't
mention what maps and types you were taking on your trip.  Without a map
showing magnetic deviation, you could end up going in circles.  We used
to take some scuba divers to Lake Superior, gave them maps and
compasses, and told them to navigate out and back (I forget the
distance).  They ended up going in an arc and did not come back to the
starting point on shore.  After swimming for awhile, they had to pop up
to peek over the surface to see where was the shore.  In my dad's
airplane, we had magnetic, inertia, and radio compasses.  We often went
into very sparsely populated areas so the radio compasses became
useless: no beacon stations.  Because of magnetic anomalies, we had the
inertia compass but it require constant recalibration: every time before
taking off, it had to be calibrated.  Even with a map and a compass, you
may have to calibrate the magnetic compass away from magnetic north to
follow the route you mapped out.  That's why the good ones have bezels
you can rotate.  Some have a adjusting screw if all you want is for the
compass to point north when you are in a known area of magnetic
deviation.

I can put you at a starting point and tell you that exactly north as
indicated currently by the compass is the town you need to find (since
your supplies will run out).  Unlikely you can travel straight north.
Roads wind around.  Walking means having to get around obstacles (lakes,
swamps, cliffs, shotgun toting farmers with no trespassing signs).  And
then there is the problem of magnetic anomalies.  Without maps, I'm not
sure what is the point of taking a compass.  Are you training for chart
making?  If you intend to only drive on roads, why take a compass?
Directions will be go so far and turn left or right at some
intersection.  A GPS-capable smartphone and Google Maps (or alternative)
can help with that - unless you are going into uncharted territory, like
the roads are actually timber trails but timbering stopped some 20 years
ago.

Doesn't sound like you are wandering that far away from civilization.
If you have troubles with knowing if you're going the wrong way on a
road (maybe you took a wrong turn) then get a car compass.  No
smartphone to grab while driving and turn on or unlock the lockscreen,
no having to load an app, no requirement for a smartphone with magnetic
sensors or even GPS, or having to dig into your pocket to pull out a
compass.  Just glance at the compass on your dash or windshield or in
the rearview mirror that has a compass.

From what you already said, your smartphone doesn't have magnetic
sensors.  A compass app won't work there.  The gear needed for an
intertial or gyroscopic compass would be much larger than the size of a
phone, as would a radio compass (radio direction finder).  Just go with
the compass you already have.  If you only on roads (that are charted)
then that's all you need (well, maps, too, if you don't have GPS in the
phone and/or you are out of range of cell towers).
0
VanguardLH
12/18/2016 9:21:49 PM
Poutnik <poutnik4nntp@gmail.com> wrote:

> Dne 18/12/2016 v 09:03 micky napsal(a):
> 
>> That's all true.   But I still want an app, especially when it's raining
>> or I don't want to stop the car to get out. 
>> 
> I would really recommend the LocusMap application.
> https://play.google.com/store/apps/details?id=menion.android.locus
> https://play.google.com/store/apps/details?id=menion.android.locus.pro
> 
> Free one with ads, paid one ads free with some extra features.
> 
> It has, aside of many feature useful for outdoor,
> also an explicit compass screen, where can be used
> direction based both on compass ( if available )
> or on GPS ( less accurate for walks, but enough for cars )
> 
> ( Picture of compass screen on the bottom )
> http://docs.locusmap.eu/doku.php?id=manual:user_guide:tools:gps
> 
> See also http://www.locusmap.eu/

But without a compass (whether a real one or as an app), how would you
know in which direction you were moving?  Those show a map around where
you are.  You would have to move far enough so there would be a change
in your location and then compare the old map to the new one to see in
which direction you moved, then repeat until you were moving in the
direction you wanted to go.

micky said his smartphone does not have magnetic sensors.  So no
compass-capable app will work.  Without a compass, how would you know
which direction matches with north in the map?  Luckily, micky has a
real compass so he could use it with LocusMap but that assumes he can
get a map for wherever he will be wandering and it had magnetic lines to
show local deviations.  If he is always on *charted* roads, magnetic
deviation isn't an issue (unless it is a severe anomaly, like the
compass points way off of north so he gets messed up on which way he is
travelling on a road).

Does LocusMap provide a map of the local area within some N miles or do
they only have a fixed catalog of maps?  I know Google Maps lets you
download (offline) a map but it's only for something like a 10-mile
radius.  Google also notes "Downloading offline areas isn't available in
some regions because of contractual limitations, language support,
address formats, or other reasons."  I think there is also a 30-day
limit on offline map retention although, if doable, they update it every
15 days or you can manually update.  From the updates list for LocusMap,
it looks like they have a catalog of maps rather than taking your
current GPS location and offloading a map for that area.  The [source of
their] catalog, however, looks pretty rich.

Sometimes the problem with maps is they can be inaccurate.  They show
where a city's plat planned to build a road but that's not where it got
built.  There's supposed to be a road here.  Nope, no road.  But it's on
the map.  They haven't built it yet, or went over there.  Why didn't the
map get changed?  Eh, close enough for them, maybe someday an update.

Also depends on what kind of roads that micky will be travelling.
Timber roads aren't planned, they aren't mapped well (the dotted line on
the map is just a general area where they are), get washed out, fallen
trees aren't removed so you have to find an alternate path, they were
iced-over  swamps in the river but you're travelling in summer, the
water level rose for the lake and the trail shore is under water, etc.
I've seen "roads" that were actually a wide shore that disappears at
high tide.  That it's on the map doesn't mean it is there, where the map
says it should be, or navigable.

From micky's description, so far, of his intended travels, I think a car
compass would suffice for his needs and be easier to use than an app on
a smartphone.  If he doesn't want a permanent one, get one with a
suction cup and stick it inside his windshield during the trip.
0
VanguardLH
12/18/2016 9:51:19 PM
Dne 18/12/2016 v 22:51 VanguardLH napsal(a):
> Poutnik <poutnik4nntp@gmail.com> wrote:
> 
>> Dne 18/12/2016 v 09:03 micky napsal(a):
>>
>>> That's all true.   But I still want an app, especially when it's raining
>>> or I don't want to stop the car to get out. 
>>>
>> I would really recommend the LocusMap application.
>> https://play.google.com/store/apps/details?id=menion.android.locus
>> https://play.google.com/store/apps/details?id=menion.android.locus.pro
>>
>> Free one with ads, paid one ads free with some extra features.
>>
>> It has, aside of many feature useful for outdoor,
>> also an explicit compass screen, where can be used
>> direction based both on compass ( if available )
>> or on GPS ( less accurate for walks, but enough for cars )
>>
>> ( Picture of compass screen on the bottom )
>> http://docs.locusmap.eu/doku.php?id=manual:user_guide:tools:gps
>>
>> See also http://www.locusmap.eu/
> 
> But without a compass (whether a real one or as an app), how would you
> know in which direction you were moving?  Those show a map around where
> you are.  You would have to move far enough so there would be a change
> in your location and then compare the old map to the new one to see in
> which direction you moved, then repeat until you were moving in the
> direction you wanted to go.

Locusmap can, depending on settings, determine the course
for the position dynamics. I am not sure it the course is calculated, or
provided directly by GPS system, both with some Kalman filtering.
I guess the latter.
For bike and car it is accurate enough.

> 
> micky said his smartphone does not have magnetic sensors.  So no
> compass-capable app will work.  Without a compass, how would you know
> which direction matches with north in the map?  Luckily, micky has a
> real compass so he could use it with LocusMap but that assumes he can
> get a map for wherever he will be wandering and it had magnetic lines to
> show local deviations.  If he is always on *charted* roads, magnetic
> deviation isn't an issue (unless it is a severe anomaly, like the
> compass points way off of north so he gets messed up on which way he is
> travelling on a road).

Sure, GPS based does not determine orientation,
but the heading of the car front while moving.
OTOH, who use Android device as a compass, uses usually also
the device based maps.

LocusMap either shows your heading on the north oriented map,
either rotate the maps together with the north marking
according your course.
> 
> Does LocusMap provide a map of the local area within some N miles or do
> they only have a fixed catalog of maps?  I know Google Maps lets you
> download (offline) a map but it's only for something like a 10-mile
> radius.  Google also notes "Downloading offline areas isn't available in
> some regions because of contractual limitations, language support,
> address formats, or other reasons."  I think there is also a 30-day
> limit on offline map retention although, if doable, they update it every
> 15 days or you can manually update.  From the updates list for LocusMap,
> it looks like they have a catalog of maps rather than taking your
> current GPS location and offloading a map for that area.  The [source of
> their] catalog, however, looks pretty rich.

Locusmap can use several types of maps
- MapsForge compatible vector maps, available for al countries.
- downloaded online raster maps, depending on licence policy
- Maps provided by the user in required formats
- online or cached online maps, if policy does not allow the download.
> 
> Sometimes the problem with maps is they can be inaccurate.  They show
> where a city's plat planned to build a road but that's not where it got
> built.  There's supposed to be a road here.  Nope, no road.  But it's on
> the map.  They haven't built it yet, or went over there.  Why didn't the
> map get changed?  Eh, close enough for them, maybe someday an update.

Well, accuracy of maps is independent topics.
Vector maps are OSM based, so the OSM map fix can be really fast
and you can do so personally.
> 
> Also depends on what kind of roads that micky will be travelling.
> Timber roads aren't planned, they aren't mapped well (the dotted line on
> the map is just a general area where they are), get washed out, fallen
> trees aren't removed so you have to find an alternate path, they were
> iced-over  swamps in the river but you're travelling in summer, the
> water level rose for the lake and the trail shore is under water, etc.
> I've seen "roads" that were actually a wide shore that disappears at
> high tide.  That it's on the map doesn't mean it is there, where the map
> says it should be, or navigable.
> 
OSM maps can map anything from motorways to path on woods.
And BRouter car profiles can route you anywhere you tell them to do so.

> From micky's description, so far, of his intended travels, I think a car
> compass would suffice for his needs and be easier to use than an app on
> a smartphone.  If he doesn't want a permanent one, get one with a
> suction cup and stick it inside his windshield during the trip.
> 
I have nothing against car mounted compasses.
With liquid stabilisation and papermaps they are very useful.


-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.
0
Poutnik
12/19/2016 7:54:26 AM
Many hand held gps devices have non magnetic type compasses. For example the 
garmin etrex 10 and etrex 20 , these  all work reasonably well but they only 
work when moving.

MJP

"micky"  wrote in message news:5k9c5cd3mq9fcqecb3mn0m7ht1rac7ilo2@4ax.com...

I need a compass app and the Play store has loads, but about half of
them say that the phone has to have a magnetometer, and from gsmarena,
it seems my Blu phone Android v.5 does not
  ( http://www.gsmarena.com/blu_studio_x_plus-6926.php )

Some of them have in big print that a magnetometer is needed and others
say nothing.   One of them that seemed really good finally said 21 lines
in "Large iron and steel objects can influence the magnetic sensor in
your Android device, "
https://play.google.com/store/apps/details?id=com.gamma.compass

So, do some not require a magnetometer?

If they don't require one, do they require nearby cell towers?    Some
of my driving won't be in cell tower range.   At least the coverage map
doesn't show coverage.

Is there some 3rd or 4th way that a compass app can figure out
direction?  (Are the answers to this the same as to "What is needed for
GPS to figure out location?")


I could just install some and go out to where  there is no cell coverage
and see if they work, except that when I signed up 7 or 10 years ago
there were areas like that for AT&T only 20 minutes away.  Now their
coverage map shows only small areas 2 hours from here, and the areas are
in the mountains and so small I don't think I can find them, especially
on foot, which I would have to be.

TIA 

0
MJP
12/19/2016 9:32:58 AM
On 2016-12-19 10:32, MJP wrote:

> I need a compass app and the Play store has loads, but about half of
> them say that the phone has to have a magnetometer, and from gsmarena,
> it seems my Blu phone Android v.5 does not
>  ( http://www.gsmarena.com/blu_studio_x_plus-6926.php )
> 
> Some of them have in big print that a magnetometer is needed and others
> say nothing.   One of them that seemed really good finally said 21 lines
> in "Large iron and steel objects can influence the magnetic sensor in
> your Android device, "
> https://play.google.com/store/apps/details?id=com.gamma.compass
> 
> So, do some not require a magnetometer?

Then they are not a compass.


> If they don't require one, do they require nearby cell towers?    Some
> of my driving won't be in cell tower range.   At least the coverage map
> doesn't show coverage.

They would need location services (either cell towers or GPS) and
movement, to calculate direction.

-- 
Cheers,
       Carlos E.R.
0
Carlos
12/19/2016 5:49:05 PM
micky wrote:

> I need a compass app and the Play store has loads, but about half of
> them say that the phone has to have a magnetometer, and from gsmarena,
> it seems my Blu phone Android v.5 does not 
>   ( http://www.gsmarena.com/blu_studio_x_plus-6926.php )
> 
> Some of them have in big print that a magnetometer is needed and others
> say nothing.   One of them that seemed really good finally said 21 lines
> in "Large iron and steel objects can influence the magnetic sensor in
> your Android device, "
> https://play.google.com/store/apps/details?id=com.gamma.compass
> 
> So, do some not require a magnetometer?   

Nope. A magnetometer *is* the compass.

> Is there some 3rd or 4th way that a compass app can figure out
> direction?  (Are the answers to this the same as to "What is needed for
> GPS to figure out location?") 

No. Some GPS based apps just show the direction of *movement* after a
few meters of recording the location - but this is not the same as a
compass.



-- 
Arno Welzel
https://arnowelzel.de
https://de-rec-fahrrad.de
http://fahrradzukunft.de
0
Arno
12/20/2016 4:52:20 AM
Poutnik <poutnik4nntp@gmail.com> wrote:

> Locusmap can, depending on settings, determine the course
> for the position dynamics. I am not sure it the course is calculated, or
> provided directly by GPS system, both with some Kalman filtering.
> I guess the latter.
> For bike and car it is accurate enough.

I'm wondering how an app that doesn't require magnetic sensors in the
smartphone can tell if you are pointing, for example, northeast or
southwest on a road - so you know you'll be heading in the correct
direction towards your destination instead of away from it.

It utilitizes GPS but that would require you travel far enough to see
where you position changed in their map.  I'm pretty good with
navigational orientation.  I'll tell someone the needed intersection is
a couple blocks further in the direction we are heading although I've
been in that area only once.  They don't agree and make a U-turn to head
in the opposite direction.  They drive and drive until they realize the
intersection would not have been that far, make another U-turn, get back
to where we were, and 2 blocks later there is the intersection.  If I
had not been there, who knows where they would've ended up.  They
thought they were going north on the road (after coming out of a maze of
roads and they got all confused as to where was north) and knew they had
to go south but they got north and south mixed up.  Perhaps not as big a
deal when driving a car (unless you are low on fuel) but tiring if you
make these mistakes when biking and a time burner if hiking.

Also found the following FAQ article saying you better not move this app
to secondary storage (SD card).  It must stay in primary (main) storage.

http://docs.locusmap.eu/doku.php?id=manual:faq:problems_since_update_to_a44
http://docs.locusmap.eu/doku.php?id=manual:faq:use_sdcard_on_kitkat

It looks like LocusMap will work with a magnetic-sensored smartphone.
The following article talks about using the "compass function" in the
smartphone:

http://docs.locusmap.eu/doku.php?id=manual:faq:how_to_calibrate_compass

The doc page below describing the settings also indicates a hardware
compass (magnetic sensors) in the smartphone are required to know in
which direction you are pointing.

http://docs.locusmap.eu/doku.php?id=manual:user_guide:settings:sensors

So micky still needs a real compass, even a cheapie, so he knows he is
headed the correction direction shown on the LocusMap and eliminate
wasted fuel and time in having to backtrack>  Sometimes backtracking is
not easy or doable until after a distance.  Try following some of the
cow pathed roads in Massachussetts where you cannot get back to where
you were before - no u-turns, no circling back using the side roads to
get back to the same road but in the opposite direction but instead
having to keep driving until you find a turnabout or bridge with an exit
ramp and a matching entrance ramp to go back.

LocusMap looks pretty good but needs a smartphone with an in-built
compass function or an external compass.  The free version is adware.
Are the ads obtrustive or hidden?  That is, do the ads occupy screen
space when you are trying to use a map or only show up in the menu or
config screens?  I remember trying a free file manager but it popped up
ads onto the screen even when I was not using it.  It got immediately
discarded.  Bad enough to have ads within the app but I won't tolerate
them popping up outside the app.  I've used apps that had in-app ads but
sometimes even those interfere with using the app (e.g., Avast wifi
finder) plus they often hide that the ads are luring the user to
payware.  Tis the bane of free apps: they are channels for monetization.

The Google Store page for LocusMap says "In-app products: $1.32 -
$134.48 per year".  Wowser!  Even for a Pro version, that's damn
expensive.  Do you ever have to pay to get a map?  From:

http://www.locusmap.eu/download/

Missing in the free version are:

- Geo-caching - Limited.  How limited?  They say offline maps is 
  available in the free version yet geocaching seems necessary to 
  locally store those offline maps.
- Tracking record - Limited.  Does this mean I cannot use GPS without 
  compass to see that I'm going in the wrong direction?
- Weather forecast - No.  Not a biggie.  Use a weather app or the 
  weather widget that comes in Android.

0
VanguardLH
12/20/2016 5:38:28 AM
Dne 20/12/2016 v 06:38 VanguardLH napsal(a):
> Poutnik <poutnik4nntp@gmail.com> wrote:
> 
>> Locusmap can, depending on settings, determine the course
>> for the position dynamics. I am not sure it the course is calculated, or
>> provided directly by GPS system, both with some Kalman filtering.
>> I guess the latter.
>> For bike and car it is accurate enough.
> 
> I'm wondering how an app that doesn't require magnetic sensors in the
> smartphone can tell if you are pointing, for example, northeast or
> southwest on a road - so you know you'll be heading in the correct
> direction towards your destination instead of away from it.

Well, the application cannot determine which direction the is poining.
It determines which direction the car is moving.

If by a chance there was an icy slicky way, your car front was pointing
upward to north, but sliding to south, the GPS direction would point to
south, while the compass direction would point to north.


> 
> It utilitizes GPS but that would require you travel far enough to see
> where you position changed in their map. 

From my own experience, a bike speed is fast enough
to realy on GPS course based on velocity vector.

> 
> It looks like LocusMap will work with a magnetic-sensored smartphone.

I have said it works. Or with velocity direction.
Or both, with the speed threshold. I use usually 8-10 km/h.

> 
> So micky still needs a real compass, even a cheapie, so he knows he is
> headed the correction direction shown on the LocusMap and eliminate
> wasted fuel and time in having to backtrack>

Not, while the car is moving at least 10 km/h or so.

> 
> LocusMap looks pretty good but needs a smartphone with an in-built
> compass function or an external compass.  The free version is adware.

No, he need not compass in context of LocusMap for usual car speed.
But yes, I DO agree the compass IS very useful
and needed for other scenarios.

> Are the ads obtrustive or hidden?  That is, do the ads occupy screen
> space when you are trying to use a map or only show up in the menu or
> config screens? 

There is a permanent ads bend. the tolerance may be a user dependent.
They may have a Xmass discount, I bought it at 50% price at Xmas
2 years ago.

> 
> The Google Store page for LocusMap says "In-app products: $1.32 -
> $134.48 per year".  Wowser!  Even for a Pro version, that's damn
> expensive.  Do you ever have to pay to get a map?  From:

It seems like a misleading info.
There is one time peayment,  I guess about 7 dollars.
Additional peymaent is just for their vector maps/update,
if you want them, like 0.5 dollar per a map.
But there are alternative free vector maps, like openandromaps.

There are also available 3rd party free and paid raster maps, paid to
the 3rd parties.

> 
> http://www.locusmap.eu/download/
> 
> Missing in the free version are:
> 
> - Geo-caching - Limited.  How limited?  They say offline maps is 
>   available in the free version yet geocaching seems necessary to 
>   locally store those offline maps.

I personally do not do GC, so look at the manual.
In contrary to Google maps, Locus is focused primarily
on offline maps, even if online maps are possible.

For outdoor usage, the signal may be weak, connection slow,
data plan expensive and connection challanges the battery.

> - Tracking record - Limited.  Does this mean I cannot use GPS without 
>   compass to see that I'm going in the wrong direction?

Of course you can.
It determine the direction from the velocity vector,
that is derived from the filtered time derivative of the position.


-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.
0
Poutnik
12/20/2016 6:36:16 AM
Dne 20/12/2016 v 07:36 Poutnik napsal(a):
> 
>>
>> The Google Store page for LocusMap says "In-app products: $1.32 -
>> $134.48 per year".  Wowser!  Even for a Pro version, that's damn
>> expensive.  Do you ever have to pay to get a map?  From:
> 
> It seems like a misleading info.
> There is one time peayment,  I guess about 7 dollars.
> Additional peymaent is just for their vector maps/update,
> if you want them, like 0.5 dollar per a map.
> But there are alternative free vector maps, like openandromaps.
> 
> There are also available 3rd party free and paid raster maps, paid to
> the 3rd parties.

A friend of mine recently said the LocusMap Pro
was the only software he had ever bought
and he did not regret it.

For free vecttor maps
http://openandromaps.org/
http://www.openandromaps.org/en/downloads/usa_en

And recommended vector map style
http://www.openandromaps.org/en/legend/elevate-mountain-hike-theme

Other styles are builtin or at forum.locusmap.eu


-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.
0
Poutnik
12/20/2016 6:52:12 AM
Dne 20/12/2016 v 07:52 Poutnik napsal(a):
> Dne 20/12/2016 v 07:36 Poutnik napsal(a):
>>

> 
> For free vecttor maps
> http://openandromaps.org/
> http://www.openandromaps.org/en/downloads/usa_en
> 
> And recommended vector map style
> http://www.openandromaps.org/en/legend/elevate-mountain-hike-theme
> 
> Other styles are builtin or at forum.locusmap.eu
> 
BTW, most of maps can be stored at the SD card,
except of online map caches or downloaded maps segments.
due Android access policies for A4.4+.

Things differ for various Android versions,
so see ther manual.



-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.
0
Poutnik
12/20/2016 6:56:04 AM
In comp.mobile.android, on Sun, 18 Dec 2016 15:21:49 -0600, VanguardLH
<V@nguard.LH> wrote:

>micky <NONONOmisc07@bigfoot.com> wrote:
>
>> I have a real compass**, and that's what I was planning to use, but I
>> won't be hiking, I'll be driving, and I think I'd have to stop the car
>> and get out every time I want to check direction.   So I"m still going
>> to take the real compass, but I want to get a compass app for the phone
>> too. 
>> 
>> ** I have one I bought, plus I have one that one wears on his wrist that
>> I found in the desk drawer when I was about 10 years old.  I finally
>> wore out the faded olive drab band and got a new band.  I'm not sure
>> which I'm going to take. 
>> 
>> I still want an app, especially when it's raining or I don't want to
>> stop the car to get out. 
>
>Why do you have to get out of the car to use a real compass?  If true,

I believe I've tried this and a real compass didn't work in the car, but
I know if was very hard to set the compensating magnets on the car
compasses I've had (that used such magnets).  That tells me that my
prior cars had a magnetic field inside them.

>why don't you have to get out of the same car to use an app on a
>smartphone using its magnetic sensors?  Magnetic compasses work inside

You're right.  Maybe I'm better off that the my phone doesn't have a
magnetic sensor.    

I haven't posted for a while because I've been searching the web. It's
interesting to see the whiners and complainers who bought a phone that
didn't claim to have a compass sensor but now blame the phone maker that
it doesn't have one. 

>of cars.  You can even buy ones to mount inside your car (although they

They have compensating magnets that have to be adjusted.  Stand-alone
compasses, like boy-scout compasses, don't  have that. 

Even the micronta electronic compass had two compensating magnets I had
to adjust, but it worked better than the non-electronic compasses
because it had a sensor and a suction cup to stick the sensor very close
to the windshield.    

>are very rudimentary).  Some rearview mirrors have them.  I'm presuming

That's where the idea came from.  I finally got around to installing my
rear view mirror w/compass, and it works great.   I was thinking of
taking the mirror and installing it on my rental car, until someone
suggested a phone app. 

>there are glass windows in your car and the dash isn't made of metal.
>
>Your smartphone doesn't have GPS?  

Yes it does.   But I coudlnt' find search terms that actually worked, to
find compass apps that could get by with GPS only.   Because even the
ones that use the internal magnetometer discuss GPS in their
description.  Even in the app name.  

I installed one that looked good, that seemed to say it would work with
GPS,  and when I first opened it, it said that there was no magnetometer
and it wouldn't work. 

But finally I found one that said, only under What's New, "works without
magnetometer".  I thought, aha, these are the magic words and I can put
them in quotes and find other apps that do that, but when I tried it,
every hit was either a discussion of the topic or it pointed to the same
app. 

When I installed this app, 

     GPS Compass Explorer, 

it too immediately gave me a warning, paraphrasing, "Your phone doesn't
have a magnetometer, but this app will work with GPS also."

>Are you taking maps, especially those that show magnetic deviation or
>anomalies?  A compass without a map is only useful to get back to where

Maps, but no reference to deviation or anomalies. 

>you started or keep you on a path already known or planned.  You didn't
>mention what maps and types you were taking on your trip.  Without a map

Probably google maps (although those expire in iirc 30 days, so I'm not
going to load them yet)  Maps.me for sure.    OSMand but I haven't
figured out how to use that.    Plus i have a map that covers 200??
miles and I have a 6x8" book that has sepearate pages for different
areas, but it's in more detail than the one page map. 

>showing magnetic deviation, you could end up going in circles.  We used

No I won't do that.  I'm not hiking.  I'm in the car.    I've never
considered magnetic deviation and I've only not known which direction to
turn about 10 times in the last 40 years.  I've only not known both
which direction to go and where I am twice in the last 40 years. 

>to take some scuba divers to Lake Superior, gave them maps and
>compasses, and told them to navigate out and back (I forget the
>distance).  They ended up going in an arc and did not come back to the
>starting point on shore.  After swimming for awhile, they had to pop up

Swimming provides even more routes than hiking does.   Any direction
they want to go, they can. 

>to peek over the surface to see where was the shore.  In my dad's
>airplane, we had magnetic, inertia, and radio compasses.  We often went

Same thing with an airplane.  But I'll be on roads that I've already
planned on the map most of the time.   When I make a turn off  the
planned route.  I don't know how to explain it but I do this all the
time and it's very rare I don't know how to get where I want to go, and
that I don't recognize the road I'm heading for, even if I approach it
from the side. 

Say I'm trying to get back to Baltiomre but I'm in a rural area I've
never been to before, there's a river between me and Balt that has only
3 bridges 40 miles apart, and the roads wind around.   This summer I
missed the road to the bridge and went about 4 miles too far south.  I
asked 4 different people at different places and they were all from
somewhere else, so finally I found a guy driving into his driveway, and
of course he lived there and knew where hte bridge was. 

But that's as bad as it's ever gotten and it was only 8 miles and 15
minutes extra. 

>into very sparsely populated areas so the radio compasses became
>useless: no beacon stations.  Because of magnetic anomalies, we had the
>inertia compass but it require constant recalibration: every time before
>taking off, it had to be calibrated.  Even with a map and a compass, you
>may have to calibrate the magnetic compass away from magnetic north to
>follow the route you mapped out.  That's why the good ones have bezels
>you can rotate.  Some have a adjusting screw if all you want is for the
>compass to point north when you are in a known area of magnetic
>deviation.

Very interesting.  Once I stopped reading this as if it applied to me,
it has become very interesting. 

>I can put you at a starting point and tell you that exactly north as
>indicated currently by the compass is the town you need to find (since
>your supplies will run out).  Unlikely you can travel straight north.
>Roads wind around.  Walking means having to get around obstacles (lakes,
>swamps, cliffs, shotgun toting farmers with no trespassing signs).  And
>then there is the problem of magnetic anomalies.  Without maps, I'm not
>sure what is the point of taking a compass.  

It would still be helpful.  If I went south in the morning, I'd have to
go north in the afternoon. 

Okay now I remember another occasion.  It was a warm fall day, October
or even November, we were driving by Soldier's Delight, a natural area a
few miles outside Baltimore, at about 5 or 5:30PM.   A girlfriend and I
started walking a blazed trail on flat land and eveyrthng was fine until
I noticed there were no more blazes.   By this time it was getting dark,
so I figured I'd just walk straight ahead and eventually we'd get out of
the woods.  It worked but we were on the far side of the woods. If I'd
had a compass, I would have gone west to the road where I was parked. 

We were going to have to walk about 2 miles to get back to the car,
though someone stopped for us after about 10 minutes.  

>Are you training for chart
>making?

I'm not going to make any charts. 

>  If you intend to only drive on roads, why take a compass?

So I'll know what direction north is. 

>Directions will be go so far and turn left or right at some
>intersection.  A GPS-capable smartphone and Google Maps (or alternative)

I have no interest in directions and I'm not going to use directions
even if one of the maps programs has it. 

>can help with that - unless you are going into uncharted territory, like
>the roads are actually timber trails but timbering stopped some 20 years
>ago.

I go on worse roads than timber trails. 

On the last trip, I saw a sign for a park and it was a nice road through
a wooded area.  I saw a couple other cars, even though it was the middle
of a weekday and most people were at work.  But I kept driving until
there were no more other cars, no trees, only rocks and scrub, but
rather than go back probably 4 miles, I figured I'd drive out the other
end.   The road got worse and worse, more and bigger rocks, and I
finally realized I couldn't go forward and it was going to be hard to
turn around.  I had a cell phone but no idea whom to call if I got
stuck, but it was about 6 miles to walk out, only 4 miles to the road,
and only 2 miles to where other park visitors might be,, and this time I
had plenty of daylight left.  So I could have done that if I had to.
But, instead of a 3-point U-turn, I made a 21-point U-turn and was able
to drive out.   So it was worse than a timber trail and since I got out,
it was a fun experience.   A compass would not have helped for that one;
my mistake was thinking there was a 2nd way in/out. 

>Doesn't sound like you are wandering that far away from civilization.
>If you have troubles with knowing if you're going the wrong way on a
>road (maybe you took a wrong turn) then get a car compass.  No

I was thinking of looking for the Micronta and connecting a cigarette
lighter plug (It was hard wired on the previous car), but I had trouble
getting the suction cut to stick and I might have had to glue it on.  I
use glue on a rental car.   Any other car compass, except the rear view
mirror, would be worse.   And the mirror presents some problems. 

**The problem with the rear view mirror compass is that I don't know if
the rental will have a power rear view mirror.  I could bring a cord
with a cigarrette plug, but I hate to have wires dangling down. I could
bring the same size torx wrench that my rear view mirror uses to hold it
in place, but I might have to buy another tool for the rental car. 

>smartphone to grab while driving and turn on or unlock the lockscreen,
>no having to load an app, no requirement for a smartphone with magnetic
>sensors or even GPS, or having to dig into your pocket to pull out a
>compass.  Just glance at the compass on your dash or windshield or in
>the rearview mirror that has a compass.

I agree that just glancing is better than using the phone.  OTOH, I'm
only going to need this once or twice in a day, maybe 5 or 10 times
altogether.   

It's no trouble to load an app, I already have a smartphone with GPS,
that I already plan to take with me in order to have a phone.  If I can
plug the phone into the cigarette lighter, I'll turn off the
self-locking.  Or I'll just turn it off anyhow, and turn off the screen
whenever I'm not using it.   When I'm alone, it will sit on the
passenger seat, so maybe I'll only have to glance at it also. 

>
>From what you already said, your smartphone doesn't have magnetic
>sensors.  A compass app won't work there.

A lot of people say that -- I found it on the web more than 10 times
tonight - but I don't see how one can fairly say that.  There are apps
that use GPS and the phone's movement along the highway to figure out
which direction one is going.   That seems to me to meet the definition
of a compass app. 

And whether it meets the definition or not, it's good enough for me. 

>  The gear needed for an
>intertial or gyroscopic compass would be much larger than the size of a
>phone, as would a radio compass (radio direction finder).  Just go with
>the compass you already have.  If you only on roads (that are charted)
>then that's all you need (well, maps, too, if you don't have GPS in the
>phone and/or you are out of range of cell towers).

I will definitely be out of range of cell towers some of the time, but
the phone has GPS.  That won't change. 

I have  GPS Compass Explorer and "Compass" on the phone now and tomorrow
or Wednesday I'll go for a drive and see how they work. If the second
one works, I'll find out it's full name and I'll let you all know if
either of these is good enough. 

Thanks for the advice, both the advice I'll take and and that I won't. 
0
micky
12/20/2016 7:38:18 AM
In comp.mobile.android, on Tue, 20 Dec 2016 05:52:20 +0100, Arno Welzel
<usenet@arnowelzel.de> wrote:

>micky wrote:
>
>> I need a compass app and the Play store has loads, but about half of
>> them say that the phone has to have a magnetometer, and from gsmarena,
>> it seems my Blu phone Android v.5 does not 
>>   ( http://www.gsmarena.com/blu_studio_x_plus-6926.php )
>> 
>> Some of them have in big print that a magnetometer is needed and others
>> say nothing.   One of them that seemed really good finally said 21 lines
>> in "Large iron and steel objects can influence the magnetic sensor in
>> your Android device, "
>> https://play.google.com/store/apps/details?id=com.gamma.compass
>> 
>> So, do some not require a magnetometer?   
>
>Nope. A magnetometer *is* the compass.
>
>> Is there some 3rd or 4th way that a compass app can figure out
>> direction?  (Are the answers to this the same as to "What is needed for
>> GPS to figure out location?") 
>
>No. Some GPS based apps just show the direction of *movement* after a
>few meters of recording the location - but this is not the same as a
>compass.

Thanks for the distinction.  It's good enough for me, whatever it's name
is.  It's only at the very start of a trip that there won't be prior
movement. and at the very start, I'll know where I am and what direction
I'm facing. 

I'm going to test a couple this week and I plan to let you all know how
well they work. 

0
micky
12/20/2016 7:52:07 AM
Dne 20/12/2016 v 08:38 micky napsal(a):


> 
> No I won't do that.  I'm not hiking.  I'm in the car.    I've never
> considered magnetic deviation [..]

the magnetic declination may be important
for exact outdoor activities,
but probably less for the car scenarios.

A useful calculator may be found here,
calculates declination for given location and time,
together with the time drift. :
https://www.ngdc.noaa.gov/geomag-web/#declination

I remember in the early 80s in former Czechoslovakia
it was below 1 degree for my city. Now it is about 4 degrees,
as the Earth magnetic field is changing and the mag. poles are moving.

The mentioned LocusMap application, if uses builtin compass,
it gives you a choice if you prefer magnetic or true north,
the latter after the correction.

-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.
0
Poutnik
12/20/2016 8:04:40 AM
Arno Welzel <usenet@arnowelzel.de> wrote in news:f9ac5087-57eb-c903-c169-
0faf96537088@arnowelzel.de:

> micky wrote:
> 
>> I need a compass app and the Play store has loads, but about half of
>> them say that the phone has to have a magnetometer, and from gsmarena,
>> it seems my Blu phone Android v.5 does not 
>>   ( http://www.gsmarena.com/blu_studio_x_plus-6926.php )
>> 
>> Some of them have in big print that a magnetometer is needed and 
others
>> say nothing.   One of them that seemed really good finally said 21 
lines
>> in "Large iron and steel objects can influence the magnetic sensor in
>> your Android device, "
>> https://play.google.com/store/apps/details?id=com.gamma.compass
>> 
>> So, do some not require a magnetometer?   
> 
> Nope. A magnetometer *is* the compass.
> 
>> Is there some 3rd or 4th way that a compass app can figure out
>> direction?  (Are the answers to this the same as to "What is needed 
for
>> GPS to figure out location?") 
> 
> No. Some GPS based apps just show the direction of *movement* after a
> few meters of recording the location - but this is not the same as a
> compass.
> 
> 
> 
Another thing to take into considerations is your case. If you have a 
case with a cover that folds back, and that puts your device to sleep 
when you close the cover, your magnetometer is screwed. There is a small 
magnet usually in the top right corner of the cover that the device 
senses and uses to go to sleep or wake up. It's the same thing as with a 
car compass or trying to use a regular compass in a car. The car's metal 
frame distorts the earth's magnetic field enough that the compass doesn't 
read correctly. A purpose built car compass has the regulating magnets 
that one adjusts to compensate, but that doesn't work for your Android 
device. And if you have used your cover long enough, even taking your 
Android out of the cover is not going to help. There will be residual 
magnetic effects left in the device from being so close to a magnet for 
so long.
Those of us who are old enough remember taking a magnet of some sort to 
an older CRT TV screen or a CRT computer monitor and seeing how it 
distorted the image. I just found out a year or two ago that all CRT 
displays are actually different; they are designed for use in either the 
Northern Hemisphere or the Southern, but not both, due to the differences 
in the Earth's magnetic field.
0
Tim
12/20/2016 8:07:51 AM
Tim wrote:

[...]
> Those of us who are old enough remember taking a magnet of some sort to 
> an older CRT TV screen or a CRT computer monitor and seeing how it 
> distorted the image. I just found out a year or two ago that all CRT 
> displays are actually different; they are designed for use in either the 
> Northern Hemisphere or the Southern, but not both, due to the differences 
> in the Earth's magnetic field.

That's the reasone why better CRT devices had a degaussing circuit built
in to fix problems with magnetization - because even just moving the
screen to a new location may cause problems.


-- 
Arno Welzel
https://arnowelzel.de
https://de-rec-fahrrad.de
http://fahrradzukunft.de
0
Arno
12/20/2016 10:56:09 AM
On 12/20/2016 11:56 AM, Arno Welzel wrote:
> Tim wrote:
>
> [...]
>> Those of us who are old enough remember taking a magnet of some sort to
>> an older CRT TV screen or a CRT computer monitor and seeing how it
>> distorted the image. I just found out a year or two ago that all CRT
>> displays are actually different; they are designed for use in either the
>> Northern Hemisphere or the Southern, but not both, due to the differences
>> in the Earth's magnetic field.
>
> That's the reasone why better CRT devices had a degaussing circuit built
> in to fix problems with magnetization - because even just moving the
> screen to a new location may cause problems.
>
>
But the degaussing purpose was not
to adapt to different static field,
but to get rid of the permanenent magnetization.

-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.
0
Poutnik
12/20/2016 12:13:01 PM
In comp.mobile.android, on Tue, 20 Dec 2016 09:04:40 +0100, Poutnik
<poutnik4nntp@gmail.com> wrote:

>Dne 20/12/2016 v 08:38 micky napsal(a):
>
>
>> 
>> No I won't do that.  I'm not hiking.  I'm in the car.    I've never
>> considered magnetic deviation [..]
>
>the magnetic declination may be important
>for exact outdoor activities,
>but probably less for the car scenarios.

Right, because one can't just drive in any direction he pleases anyhow.
You have to stay on a road. 
>
>A useful calculator may be found here,
>calculates declination for given location and time,
>together with the time drift. :
>https://www.ngdc.noaa.gov/geomag-web/#declination
>
>I remember in the early 80s in former Czechoslovakia
>it was below 1 degree for my city. Now it is about 4 degrees,
>as the Earth magnetic field is changing and the mag. poles are moving.

No, it's because you pushed out the communists and now they're getting
even. 

>The mentioned LocusMap application, if uses builtin compass,
>it gives you a choice if you prefer magnetic or true north,
>the latter after the correction.

okay. 
0
micky
12/20/2016 9:24:52 PM
In comp.mobile.android, on Tue, 20 Dec 2016 02:07:51 -0600, Tim
<timothybil@yahoo.com> wrote:

>Arno Welzel <usenet@arnowelzel.de> wrote in news:f9ac5087-57eb-c903-c169-
>0faf96537088@arnowelzel.de:
>
>> micky wrote:
>> 
>>> I need a compass app and the Play store has loads, but about half of
>>> them say that the phone has to have a magnetometer, and from gsmarena,
>>> it seems my Blu phone Android v.5 does not 
>>>   ( http://www.gsmarena.com/blu_studio_x_plus-6926.php )
>>> 
>>> Some of them have in big print that a magnetometer is needed and 
>others
>>> say nothing.   One of them that seemed really good finally said 21 
>lines
>>> in "Large iron and steel objects can influence the magnetic sensor in
>>> your Android device, "
>>> https://play.google.com/store/apps/details?id=com.gamma.compass
>>> 
>>> So, do some not require a magnetometer?   
>> 
>> Nope. A magnetometer *is* the compass.
>> 
>>> Is there some 3rd or 4th way that a compass app can figure out
>>> direction?  (Are the answers to this the same as to "What is needed 
>for
>>> GPS to figure out location?") 
>> 
>> No. Some GPS based apps just show the direction of *movement* after a
>> few meters of recording the location - but this is not the same as a
>> compass.
>> 
>> 
>> 
>Another thing to take into considerations is your case. If you have a 
>case with a cover that folds back, and that puts your device to sleep 
>when you close the cover, your magnetometer is screwed. There is a small 
>magnet usually in the top right corner of the cover that the device 
>senses and uses to go to sleep or wake up. It's the same thing as with a 
>car compass or trying to use a regular compass in a car. The car's metal 
>frame distorts the earth's magnetic field enough that the compass doesn't 
>read correctly. A purpose built car compass has the regulating magnets 
>that one adjusts to compensate, but that doesn't work for your Android 
>device. And if you have used your cover long enough, even taking your 
>Android out of the cover is not going to help. There will be residual 
>magnetic effects left in the device from being so close to a magnet for 
>so long.
>Those of us who are old enough remember taking a magnet of some sort to 
>an older CRT TV screen or a CRT computer monitor and seeing how it 

I don't have to be that old.  I have 6 crt tvs I use on a  regular
basis.   Plus I have some spares for when one of these breaks.. 

One sits under a bigger than some wireless speaker, and the speaker
makes the closest corner of the screen green.  There is no point in
degaussing it because the next time I use the speaker the same thing
will happen. 

But what's interesting is that I can rarely see the green.   it's only
if the screen there is... maybe white, or blue, I can't remember. 

>distorted the image. I just found out a year or two ago that all CRT 
>displays are actually different; they are designed for use in either the 
>Northern Hemisphere or the Southern, but not both, due to the differences 
>in the Earth's magnetic field.

That's quite amazing, in itself and that I've gone all these years
without knowing about it. 
0
micky
12/20/2016 9:31:25 PM
micky <NONONOmisc07@bigfoot.com> wrote:

> VanguardLH
>
>> Some rearview mirrors have [an electronic compass].
> 
> That's where the idea came from.  I finally got around to installing my
> rear view mirror w/compass, and it works great.   

My aunt totalled her car.  Had all the bells and whistles.  When she
drove my car, she noted there wasn't a compass in the rearview mirror.
She was used to having that (and several other goodies in my car - same
brand and model but not the 35th anniversary special edition with all
the extras, like motorized seat position and double sunroofs and ...).

When I was looking online at Walmart for hand compasses, I noticed they
have a rearview mirror with one.  Probably requires a battery since
obviously there are no wires running up the windshielf to them.  They're
pricey, though.  

> I coudlnt' find search terms that actually worked, to find compass
> apps that could get by with GPS only.   

According to poutnik's suggesting of LocusMap (or probably for any
GPS-aware mapping app) and looking at some user reports, and for a phone
without magnetic sensors but *with* GPS, you could figure which
direction you were heading after moving several meters.  That would be
enough for your GPS position to change so you would know from how you
moved as to where you should move.  Some called it inertial navigation
but that's not true, Just after-the fact corrected navigation.

With GPS, you would see where you are.  If you started driving down a
road and checked to see where you were after a couple minutes, you could
tell if you were the right or wrong way on the road.  Alas, turning back
to go the right way isn't always easy.  You may not be allowed or
incapable of making a u-turn.  It could be miles before there is an
intersection, and that might let you swing back and instead you have to
find out how to back on the same road in the opposite direction by
taking other roads.  The GPS-aware mapping app would probably help with
that.

> **The problem with the rear view mirror compass is that I don't know if
> the rental will have a power rear view mirror.  

The rearview compass mirror will also have magnetic sensors.  If it
works then a compass would work, too.  You could use a suction cupped
non-power compass to stick on the inside of the windshield.  If you are
driving at night and need the compass lighted, some come with a battery.

> I could bring a cord with a cigarrette plug, but I hate to have wires
> dangling down. I could bring the same size torx wrench that my rear
> view mirror uses to hold it in place, but I might have to buy another
> tool for the rental car. 

I wouldn't be dismantling stuff on the rental car.  If you break it,
imagine what they will charge you for replacement (parts, labor, and
some will attempt to collect a loss-of-use charge).

> I will definitely be out of range of cell towers some of the time, but
> the phone has GPS.  That won't change. 

Then, even without a compass and as long as you stay on charted roads,
you can find out after a very short drive if you are headed in the right
or wrong direction on a road.
0
VanguardLH
12/21/2016 1:39:25 AM
Dne 21/12/2016 v 02:39 VanguardLH napsal(a):

> [...]  Some called it inertial navigation
> but that's not true, Just after-the fact corrected navigation.

Inertial navigation is based on gyroscopes, either classical mechanical,
or in latest years on solid state micro/nano mechanics.
GPS direction is based on filtered velocity vector.
For car it is more stable than compass direction,
that is vulnerable to vibrations.

-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.
0
Poutnik
12/21/2016 5:58:18 AM
Poutnik <poutnik4nntp@gmail.com> wrote:

> Dne 21/12/2016 v 02:39 VanguardLH napsal(a):
> 
>> [...]  Some called it inertial navigation
>> but that's not true, Just after-the fact corrected navigation.
> 
> Inertial navigation is based on gyroscopes, either classical mechanical,
> or in latest years on solid state micro/nano mechanics.
> GPS direction is based on filtered velocity vector.
> For car it is more stable than compass direction,
> that is vulnerable to vibrations.

I was referring to the incorrect usage of "inertial" that I've seen some
users claim regarding GPS-aware smartphones and using a GPS map app.
There's nothing inertia about that scheme.
0
VanguardLH
12/22/2016 1:28:32 AM
Dne 22/12/2016 v 02:28 VanguardLH napsal(a):
> Poutnik <poutnik4nntp@gmail.com> wrote:
> 
>> Dne 21/12/2016 v 02:39 VanguardLH napsal(a):
>>
>>> [...]  Some called it inertial navigation
>>> but that's not true, Just after-the fact corrected navigation.
>>
>> Inertial navigation is based on gyroscopes, either classical mechanical,
>> or in latest years on solid state micro/nano mechanics.
>> GPS direction is based on filtered velocity vector.
>> For car it is more stable than compass direction,
>> that is vulnerable to vibrations.
> 
> I was referring to the incorrect usage of "inertial" that I've seen some
> users claim regarding GPS-aware smartphones and using a GPS map app.
> There's nothing inertia about that scheme.
> 
My post was meant just as a complement,
not arguing with you getting it wrong. :-)

-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.
0
Poutnik
12/22/2016 5:49:04 AM
Dne 22/12/2016 v 06:49 Poutnik napsal(a):
> Dne 22/12/2016 v 02:28 VanguardLH napsal(a):
>> Poutnik <poutnik4nntp@gmail.com> wrote:
>>
>>> Dne 21/12/2016 v 02:39 VanguardLH napsal(a):
>>>
>>>> [...]  Some called it inertial navigation
>>>> but that's not true, Just after-the fact corrected navigation.
>>>
>>> Inertial navigation is based on gyroscopes, either classical mechanical,
>>> or in latest years on solid state micro/nano mechanics.
>>> GPS direction is based on filtered velocity vector.
>>> For car it is more stable than compass direction,
>>> that is vulnerable to vibrations.
>>
>> I was referring to the incorrect usage of "inertial" that I've seen some
>> users claim regarding GPS-aware smartphones and using a GPS map app.
>> There's nothing inertia about that scheme.
>>
> My post was meant just as a complement,
> not arguing with you getting it wrong. :-)
> 
OTOH, some device-application combinations
may combine long term stability of GPS direction
with short term stability of true inertial method.


-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.
0
Poutnik
12/22/2016 6:18:51 AM
In comp.mobile.android, on Tue, 20 Dec 2016 19:39:25 -0600, VanguardLH
<V@nguard.LH> wrote:

>micky <NONONOmisc07@bigfoot.com> wrote:
>
>> VanguardLH
>>
>>> Some rearview mirrors have [an electronic compass].
>> 
>> That's where the idea came from.  I finally got around to installing my
>> rear view mirror w/compass, and it works great.   
>
>My aunt totalled her car.  Had all the bells and whistles.  When she
>drove my car, she noted there wasn't a compass in the rearview mirror.
>She was used to having that (and several other goodies in my car - same
>brand and model but not the 35th anniversary special edition with all
>the extras, like motorized seat position and double sunroofs and ...).
>
>When I was looking online at Walmart for hand compasses, I noticed they

The web is a strange place.  I went to Walmart.com and searched for
rear-view mirror.  It said the first page had 20 out of 24,856 results.
I dont' think there are 24 thousand models of rear-view mirror. 

When I added   compass, it said it had 81 results!   I see they have
quite a few Gentek.  There are probably only 2 models, depending on how
it attaches to the windshield, camlock or the other kind, but they are
pretending they sell different models for each make of car.  That's
okay, it makes the buyer more confident. 

>have a rearview mirror with one.  Probably requires a battery since
>obviously there are no wires running up the windshielf to them.  

That's not obvious.  It might be true on a cheap car I plan to rent.
More and more cars have electric rear view mirrors, so the + and - are
already there.   My 2000 Toyota Solara came with one.  All it did was
act as a day/night mirror, which frankly is sort of silly since a tinted
mirror is almost as good.    Makers have forgotten some of the
"secrets"** of making a convertible, and one is that you can't use a
day-night mirror that changes from day to night by pushing a lever on
the bottom (because there is a prism inside.)  When you have one of
those and the top is down at night, the cars behind you are reflected by
one surface of the prism, but every street light is refelected by the
other.  That's when I learned to buy a clip-on mirror, and it was nice
because they sell extra-wide convex. 


>They're
>pricey, though.  

They sure are.  One 485 but that includes a video screen.  Have to buy
the back-up camera separately. 

I think I saw a guy at red light (and driving away from it) last year
who was watching a movie on his rearview mirror, on the screen meant for
the back-up camera.  It was dark and he wasn't in reverse, so he must
have watching a movie!

Actually, despite walmart's claim of being cheap, I'm sure one can get
these for less money, but no time to look now. 

Wow, this one
https://www.walmart.com/ip/GenTex-2013-2014-Toyota-Tacoma-Auto-Dimming-with-Mirror-3-3-RCD-Compass-HomeLink-Temp-50-2013TACK3350/117360658
is 679.  but it has HomeLink, which will control things inside the
house.  Not my house. I have nothing that can be controlled that way. 
(I would like a front door lock that unlocks with a fob like a car, but
either they don't make them or I don't like the ones they make, I
forget.)

>> I coudlnt' find search terms that actually worked, to find compass
>> apps that could get by with GPS only.   
>
>According to poutnik's suggesting of LocusMap (or probably for any
>GPS-aware mapping app) and looking at some user reports, and for a phone
>without magnetic sensors but *with* GPS, you could figure which
>direction you were heading after moving several meters.  That would be
>enough for your GPS position to change so you would know from how you
>moved as to where you should move.  

That would be very good.  . I looked at LocusMap and it seems to have a
lot more than I need, so I'm still looking for a simple compass program
that will work based on GPS. Even the simple ones have more than I need
but maybe not so much more.   But I'll remember that LocusMap has that.
Thanks

>Some called it inertial navigation
>but that's not true, Just after-the fact corrected navigation.

I believe you.  There is a lot of a) exaggeration, b) not understanding
one's own topic, in this world. 
>
>With GPS, you would see where you are.  If you started driving down a
>road and checked to see where you were after a couple minutes, you could
>tell if you were the right or wrong way on the road.  Alas, turning back
>to go the right way isn't always easy.  You may not be allowed or
>incapable of making a u-turn.  It could be miles before there is an

On xways that could be true, but I don't drive on xways unless I'm in a
hurry to get somewhere, or I'm going the same place I've been to several
times before.   I drove from Baltimore to Dalllas and back and only
about 20% was on xways.   On some country roads, especially the road
everyone used until they built the xway,  you can go 60 and still see a
lot more than on xways.   Trees and fields are pretty, but they bore
me. I'd rather see buildings, even billboards.

Other than that, I can make a U-turn almost anywhere.  I trained in NY.
Shortly after I'd gotten there, I got stuck in a traffic jam, and I was
only 23 and I asked the girl next to me if it was legal to make a U-turn
in NYC and she said, "I think so but only at an intersection." !!
That's the one place it's probably illegal.  But I did it, in the middle
of the block, and it took a bit of time because it was bumper to bumper,
and while I was in the middle of it, there was a cop car coming the
oppposite of my original direction.  But he just drove on without even
looking at me.  

Years later I was on Atlantic Avenue, a very wide street, very near
downtown Brooklyn, on a longer than average block (without
intersections) and while I was making a U-turn, another guy was making
one just opposite me, like this  ( ), and then I looked back and there
were two other pairs of cars making U-turns.  Both of them in unison
with us.  It was like a square dance. 

>intersection, and that might let you swing back and instead you have to
>find out how to back on the same road in the opposite direction by
>taking other roads.  The GPS-aware mapping app would probably help with
>that.
>
>> **The problem with the rear view mirror compass is that I don't know if
>> the rental will have a power rear view mirror.  
>
>The rearview compass mirror will also have magnetic sensors.  If it

Yes, they have something like what cellphones have.  They too are
"calibrated' by driving around in circles. 

>works then a compass would work, too.  You could use a suction cupped
>non-power compass to stick on the inside of the windshield.  If you are

It won't be close enough to the outside, because of the bracket.   At
least that was the problem the last time. 

>driving at night and need the compass lighted, some come with a battery.

 I spent years trying to get a compass with 2 compensating magnets to
work, and I coudln't, and I'm not going to spend part of my vacation
doing the same fruitless job. 

On a separate topic, I remember now that I also had a plastic sphere,
less than 1", with a suction cup, no compensating magnet, and it
actually worked better than the suction-cup non-power compass, what you
just suggested, I guess because it was closer to the outside.
Eventually it lost too much water to work. 

I coudln't find the same thing but I found something similar for $2.50
including shipping!  I"m going to order it. 

>> I could bring a cord with a cigarrette plug, but I hate to have wires
>> dangling down. I could bring the same size torx wrench that my rear
>> view mirror uses to hold it in place, but I might have to buy another
>> tool for the rental car. 
>
>I wouldn't be dismantling stuff on the rental car.  If you break it,
>imagine what they will charge you for replacement (parts, labor, and
>some will attempt to collect a loss-of-use charge).

You have a good point there.   Of course, I think I'll never break it. 

>> I will definitely be out of range of cell towers some of the time, but
>> the phone has GPS.  That won't change. 
>
>Then, even without a compass

Even one of apps I found that will determine direction from GPS seems to
say a compass has use magnetism. I disagree. 

I say that if it shows whether you are going N, S, E or W, it's a
compass, even if it only relies on GPS satellites.  

> and as long as you stay on charted roads,

Why do they have to be charted?   

>you can find out after a very short drive if you are headed in the right
>or wrong direction on a road.

Right. 
0
micky
12/22/2016 6:40:59 AM
I loaded two compass apps 2 nights ago and tried them today.  Compass
GPS by Agbalyan did nothing (it must need a magnetometer), and the other
did nothing the first two times I turned it on, but the third time it
started to work  It worked but every time I stopped moving, it reverted
to pointing north.   I don't know why it coudln't just stay where it
was.   It's a real problem:  I may not see the setting before it
reverts, and even if I do, I might forget what I saw 5 or 10 seconds
later. 

Other than that it worked pretty well.  I lay it on the seat next to me
with something under one side to tip it towars me a little.

I had to keep my eye on the road so I'm not sure about the time, but I
think it found the new direction in 5 or at most 10 seconds. 

Of course when I pulled up to a stop sign and turned 45 degrees in the
last 5 seconds, it's not going to figure that out. But I can usually
remember the direction I  was going before I stiooped. 

However, the reverting is a big problem.   The icon is named GPS
Explorer, although on the web it was called GPS Compass Explorer. 


I found a page called "Top apps for 'compass without magnetic sensor' on
Google Play in United States - 50 results"  Unfortunately it's not true.
Those 4 words appear in only one description, and even most of the ones
with "GPS" in their name can't find direction without the magnetometer. 

But one says it can*** and 3 others might be able to (I checked and I
don't think those 3 do either.) .

Another problem is that most have simillar names and after I've
installed it, it's hard to find a reference to the name it's listed
under on the web.  Some are just called Compass. 

***The new front-runner is GPS Compass Basic, which even has a manual!
But in the manual it just calls it GPS Compass,    Once I settle on one
or two, I'll be able to keep track. 

The manual says 
"GPS Compass combines GPS and
magnetic compass to overcome magnetic
compass limitations.

GPS Compass can act as a normal
magnetic Compass or can be driven by
GPS data.

The compass color is white when driven by magnetic compass, is yellow
when driven by GPS  and is grayed when GPS compass is selected but GPS
is not available.      

There is also a third option "Automatic compass mode" that changes
automatically from magnetic to GPS  based on the availability of data
from GPS, if GPS speed and direction are not available then magnetic
compass is used....."

So this one actually relies on GPS more than magnetic, even when both
are available. 

"Given the coarse accuracy of magnetic compass, GPS Compass provides a
second way  to take bearings. The second way is completely based on GPS.
The GPS based bearing is a 2 steps procedure. In the first step a
reference direction is acquired and memorized, in the second step the
reference is used. The first step can be done once for many bearings. "

To get direction, you have go faster than 3MPH.   So I installed it just
now, but I'm not moving at all so I'll have to wait until tomorrow to
test it. 



The one I used today had an almost entirely black screen, but it still
ran the battery down at an appreciable rate.  10% in less than an hour.
The phone labeled it as a high power user.   The new one, GPS Compass
Basic has a lot more white areas than that one so doesnt' that mean it
will use even more power?   

Or is it the calculating it has to do that uses the power?  Well, not to
get direction.  That's just a matter of subtracing old lat and longitude
from th new ones and a fairly simple formula to determine direction. 

0
micky
12/22/2016 7:35:19 AM
On Thu, 22 Dec 2016 01:40:59 -0500, micky wrote:

> ... I would like a front door lock that unlocks with a fob like a car ...

And would you like to run out to the HW store at 3:30 am, after your drive
in from that late-arriving return flight from Afghanistan, to pick up a new
CR-2025 because the one in your fob died and you can't unlock that door?

 :-) . Cheers, -- tlvp
-- 
Avant de repondre, jeter la poubelle, SVP.
0
tlvp
12/22/2016 9:35:38 AM
In comp.mobile.android, on Thu, 22 Dec 2016 04:35:38 -0500, tlvp
<mPiOsUcB.EtLlLvEp@att.net> wrote:

>On Thu, 22 Dec 2016 01:40:59 -0500, micky wrote:
>
>> ... I would like a front door lock that unlocks with a fob like a car ...
>
>And would you like to run out to the HW store at 3:30 am, after your drive
>in from that late-arriving return flight from Afghanistan, to pick up a new
>CR-2025 because the one in your fob died and you can't unlock that door?

You think you got me, huh?  There would be a key backup, just like on my
car. 

>
> :-) . Cheers, -- tlvp

0
micky
12/22/2016 3:50:08 PM
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