Map projection in ENVI

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Hi everyone,
I would like to reproject the NCEP/NCAR Reanalysis I/surface flux 1.8
deg resolution datasets of air temperature (2m-daily), pressure
(daily) and wind (U/V-daily) from the geographic lat/lon to the Polar
Stereographic projection using ENVI and the spatial resolution should
be brought to either 1 km or 6.25 km. I tried by using the Convert map
projection tool in ENVI but I am not getting the desired final result.
Please help.
0
Reply kamal 6/8/2010 8:05:54 AM

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kamal writes: 

> I would like to reproject the NCEP/NCAR Reanalysis I/surface flux 1.8
> deg resolution datasets of air temperature (2m-daily), pressure
> (daily) and wind (U/V-daily) from the geographic lat/lon to the Polar
> Stereographic projection using ENVI and the spatial resolution should
> be brought to either 1 km or 6.25 km. I tried by using the Convert map
> projection tool in ENVI but I am not getting the desired final result.

What kind of result did you get?

Cheers,

David



-- 
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
0
Reply David 6/8/2010 12:44:41 PM

On Jun 8, 5:44=A0pm, David Fanning <n...@dfanning.com> wrote:
> kamal writes:
> > I would like to reproject the NCEP/NCAR Reanalysis I/surface flux 1.8
> > deg resolution datasets of air temperature (2m-daily), pressure
> > (daily) and wind (U/V-daily) from the geographic lat/lon to the Polar
> > Stereographic projection using ENVI and the spatial resolution should
> > be brought to either 1 km or 6.25 km. I tried by using the Convert map
> > projection tool in ENVI but I am not getting the desired final result.
>
> What kind of result did you get?
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.dfanning.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")

Some distorted type of image. The lat/lon vlaues and the parameter
values are all assigned to each pixel but the image seems to be, I
don't know, not correct.
Is it possible to regrid the coarse resolution to a higher resolution
using some interpolation method in ENVI (not in IDL!) and also change
the map projection?

Kamal
0
Reply kamal 6/9/2010 10:16:51 AM

kamal writes: 

> Some distorted type of image. The lat/lon vlaues and the parameter
> values are all assigned to each pixel but the image seems to be, I
> don't know, not correct.

There is probably much in ENVI to improve, but
personally, I feel great confidence in their map
projection software. At least in my case, every
time I have tried to confirm a result that seemed
"strange" to me, the problem turned out to be a 
faulty assumption or incomplete knowledge on my
part, rather than a problem with the software.

> Is it possible to regrid the coarse resolution to a higher resolution
> using some interpolation method in ENVI (not in IDL!) and also change
> the map projection?

Regrid to a higher resolution using what information?
If you start with low resolution data, producing high
resolution output is imaginary art, not science. :-)

Cheers,

David
-- 
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
0
Reply David 6/9/2010 11:04:49 AM

On Jun 9, 4:04=A0pm, David Fanning <n...@dfanning.com> wrote:

> There is probably much in ENVI to improve, but
> personally, I feel great confidence in their map
> projection software. At least in my case, every
> time I have tried to confirm a result that seemed
> "strange" to me, the problem turned out to be a
> faulty assumption or incomplete knowledge on my
> part, rather than a problem with the software.

>
> Regrid to a higher resolution using what information?
> If you start with low resolution data, producing high
> resolution output is imaginary art, not science. :-)
>
> Cheers,
>
> David
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.dfanning.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")

Thank you so much for your reply David. The original data is in
~1.8X1.8 degree spatial resolution in geographic lat/lon projection. I
want to reproject it into polar stereographic projection (North) so
that I can compare it with the AMSR-E L3 gridded data (which are in
polar stereographic projection).
0
Reply kamal 6/11/2010 3:22:30 PM
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