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#### How to fit data to a line on a log-log plot

```I finally figured out how to fit data to a line using Gnuplot.  It
works great and is relatively easy to use.  I need help with extending
this to log-log plots.

I have my data in a file (columns 4:5:6).  I can plot this on a log-
log plot easy enough.  I want to fit a line through the data so it
looks linear on the log-log plot.  That means I have to fit my data
through the line

log(y) = m* log(x) + b.

Can someone help me understand how to do this?

Thanks,
Jeremy
```
 0
jeremito
5/15/2008 6:04:25 PM
comp.graphics.apps.gnuplot 5008 articles. 0 followers.

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```jeremito  <jeremit0@gmail.com> wrote:
>That means I have to fit my data through the line

Other way around:  fit the line to the data.

>log(y) = m* log(x) + b.

1. restate this as y = etc
2. use the gnuplot 'fit' command

Una

```
 0
una
5/15/2008 7:03:04 PM
```On May 15, 3:03=A0pm, u...@att.net (Una) wrote:
> jeremito =A0<jerem...@gmail.com> wrote:
> >That means I have to fit my data through the line
>
> Other way around: =A0fit the line to the data.
Of course, my mistake.
>
> >log(y) =3D m* log(x) + b.
>
> 1. restate this as y =3D etc
> 2. use the gnuplot 'fit' command

That's easy enough if I can remember my logarithm rules.  I was afraid
I'd have to do some crazy gnuplot magic ( log10(\$1) ) etc.

Thanks,
Jeremy

```
 0
jeremito
5/15/2008 7:34:09 PM

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