SV: [GRASS-user] Raster legend

[Nikos Alexandris]

On Thu, 2009-10-08 at 14:13 +0200, Martin Album Ytre-Eide wrote:
> Thanks, but It did not seem to work, or I have not tried what you
> suggested.
>  
> The actual values are contained in the logarithmic, and that's fine.
> It is no problem converting the raster to non logarithmic with
> r.mapcalc, but it does not help me much.


> I cant use legend values from the non-logarithmic with the logarithmic
> raster since the scaling will not be right.

Right!

 
> I have just used standard rules, but done some experiments with custom
> made without any luck.
>  
> I edited the rules in colr/directory as you described. It certainly
> did something, but not the intended. And I have yet not managed to get
> de-logged values in the legend.

> Have tried a lot of things, but I don't really understand the logic in
> the colr-files.
 
> Any more/other ideas?

Maybe I don't understand this correctly but all you need is to overlay a
non-logarithmic legend derived from a logarithmic scaled raster.

Is it just to have the legend/ colors? Maybe it is silly, but given that
you successfully converted the log.raster to non-log. (as Hamish
suggested) then why don't you draw the (non-log.raster) legend for it
and try to match colors?

I think that this is what Hamish suggests actually. Disregard this
message if I am wrong/ add more confusion.

Nikos



> -----Opprinnelig melding-----

Martin Album Ytre-Eide wrote:
> > I am displaying a raster where the values are logarithmic and that
> is
> > fine. The d.legend gives me a nice legend, but I would like to
> convert
> > the values in the legend to non logarithmic values (keeping the
> raster
> > as it is). I can't find a way to do this in d.legend or r.colors.
> >
> > How is this done?

Hamish: 
> Are the actual values contained in the logarithmic? eg convert back to
> normal with r.mapcalc pow(e, MAP) or pow(10, MAP)?
>  
> are the rules custom made?
> does 'd.legend use=' help?
>  
> note the legend used does not have to match the raster it shows on,
> you could do a trick where you make a list of the values you want on
> the legend, calculate that their logs are, use r.what.color to find
> the matching color, then use those colors with the de-logged values.
>  
> probably easier actually to copy the internal rules file in the
> MAPSET's colr/ directory, convert the first column and range to de-
> logged version, perhaps run r.mapcalc to make a delogged version of
> the map (or any, just to get the range), copy in the adjusted colr/
> file into the colr/ dir, then use that map for the legend.
>  
> does that make some sense? 
> Hamish