[GRASS-user] combining r.cross and reclassification

Wout Bijkerk wout.bijkerk at xs4all.nl
Wed Aug 13 04:00:45 EDT 2008

Hello everybody,

As a former user of SPANS, I was charmed by its possibillity of making a
cross of two raster maps and reclassifying it as well within one module.
It worked with a table written in a text file, where the row and column
headers represent the category values of the input maps, while the cells
give the category values that are assigned to the combination of the two
input maps. For exaple, suppose we heve two suitabillity assignmens for
different criteria (say temperature and soil-type, where 1 is not
suitable, 2 is marginally suitable and 3 is well suitable) and we want
to make an overall suitabillity. I then made a table as below:

        1   2   3    
1      1   1   1
2      1   1  2 
3      1   2   3

This table was the input for the crossing of the suitabillity map for
temparature and the suitabillity map for soils. The result was an new
raster map, with categories ranging from 1 - 3.

Is there something like this in Grass as well? Of course one can write
long if-statements with mapcalc, but the way SPANS had it organised was
more clear and more flexible.



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