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

Barry Rowlingson b.rowlingson at lancaster.ac.uk
Fri Nov 28 14:53:53 EST 2008

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.

 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).

 For the gui I think I'll have some way of defining raster bands as R1
to Rn, and then an input line for the expression and a file to save
the result. As before, all rasters will need to be the same size and
spatial location.

 Anyone got any suggestions/requests for this?


More information about the Qgis-developer mailing list