[Qgis-developer] raster algebra plugin II - the return!

Martin Dobias wonder.sk at gmail.com
Sat Nov 29 12:17:07 EST 2008

On Fri, Nov 28, 2008 at 8:53 PM, Barry Rowlingson
<b.rowlingson at lancaster.ac.uk> wrote:
> Hi all,
>  my old raster algebra plugin was a bit creaky and limited in its
> functionality. I think it was the second plugin I wrote and it shows.
>  So after someone emailed me to say they were actually using it, I
> figured I should put some time into its successor.
>  What I'm doing is writing a parser for a mini-language for raster
> processing. So you can write something like:
>  (max(R1)-min(R1)) * sqrt(R1*R1 + R2*R2)
>  and get a new raster with the computed values in.

This sounds good. I hope there are tools like flex/bison avaiable also
for python...

>  R1 and R2 (and R3 up to Rn) will be raster bands (old rasteralgebra
> only liked single-band rasters) and the range of available functions
> and operators will be taken from things that python's numpy module
> provides for array operations (and that make sense as geo-rasters).

I guess these 'Rn' bands can be assigned from more raster layers, right?


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