Also
r.statistics method=min
and
r.statistics method=max
seems to work only for the first category of a map.
I'm working with a landuse map and a DSM (as cover).
r.statistics base=landuse cover=dsm method=min output=landuse.height
produces a map with the min of a single landuse type (the one with
category "1").
To produce the map containing all the landuse types, I have to loop
r.statistics for i from 1 to the category count of the basemap deleting
the (i-1)-th category from the basemap at every step.
It takes quite long for the maps with hundreds of categories, but at
least it works.
Make a file of it and chmod it to use.
Hopefully useful for someone else.
Bye,
RafDouglas Candidi Tommasi Crudeli
________________________ ________________________ ________________________
#!/bin/bash
# change the following two lines to match your names.
basemap=NameOfYourBaseMap
DSM=NameOfYourCoverMap
g.region -a $basemap
# this is to work with a map we don't care if it's altered:
r.mapcalc "TheMask=$basemap"
# we find out the maximum number of cats we have in the map
# My basemap originates from "v.alabel -i", so in my case
# NofCat=maximum number of cats=number of cats.
# Anyway, if there are some unused cats, it shouldn't be a problem
NofCat=$(r.info TheMask|grep Range|awk -F "=" '{print $3}'|sed 's/
*\||*\| *//g')
j=$[$NofCat]
i=1
# this cicle of r.statistics is done with the nubmer of the _first_
category
# increasing at every step.
let j+=1
until [ $i = $j ];
do
echo "cycle $i of $j"
r.statistics cover=$DSM base=TheMask method=min output=tempstat
r.mapcalc
"$landuse.height=if((isnull(@tempstat)),$landuse.height,@tempstat)"
# the next line nullifies all the cells in
# TheMask whose value is lower than $i
r.mapcalc "TheMask=if($basemap<=$i,null(),$basemap)"
let i+=1
done
g.remove rast=tempstat
g.remove rast=TheMask
d.rast $landuse.height
________________________ ________________________ ________________________
__________________________________________
RafDouglas Candidi Tommasi Crudeli
ct@ehleng.com
"To know, to will, to dare, to be silent."