[GRASSLIST:8474] Re: converting raster value of 0 (black) to null

[David Finlayson]

Do you have 2 equal signs in your logic statment?

David

On 10/3/05, Ed Davison <bfdi533 at cbacc-security3.mccombs.utexas.edu> wrote:
> I have a radar map that has a 0 value for black.  This came from a
> grayscale GeoTIFF.
>
> I need to convert the 0 value to null so that I can overlay it onto a
> base map.
>
> I have tried using mapcalc with the following:
>
> radarnew=if(radar=0,null(),radar)
>
> but this produces a magenta raster map with no other data in it.
>
> r.mapcalc is very new to me and I cannot seem to make heads of tails of
> how to do this from reading the man page.  Any pointers would be great.
>
>
> --
>
> --------------------------
> Ed Davison
>
>


--
David Finlayson
Marine Geology & Geophysics
School of Oceanography
Box 357940
University of Washington
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USA

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