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

Barry Rowlingson b.rowlingson at lancaster.ac.uk
Sat Nov 29 13:13:51 EST 2008

2008/11/29 Martin Dobias <wonder.sk at gmail.com>:

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

 Yeah, I'm using 'pyparsing', which gives you a very easy way to
specify a grammar. It's not included with python so it'll be an
external requirement - along with numpy for doing the computations.
I'm still leaning how to write these grammar things though.

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

 Yeah, the idea is that you set Rn to be bands from raster layers,
then you write an expression with Rn in it, and you get back a new

 There's a few aspects of the GUI I'm not sure of though. I also think
the plugin will provide some useful python functions too for people to
use in the python console if they need more complex processing


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