[GRASS-dev] r.infer, r.weight, r.combine vs r.mapcalc

[Hamish]

Moritz Lennert wrote:
> Looking into the potential of using GRASS for multi-criteria analysis,
> I came upon Peter Löwe's article about r.infer in GRASS News Vol. 3
[1]. 
> He also mentions r.weight and r.combine in the article (all from 5.4, 
> never ported to 6.x). I'm not sure I completely understand what these 
> three can do what r.mapcalc cannot do. Is it only a question of ease of
> usage ?

(no idea)

> If they do prove to be of added value, are there any people out there 
> who would be interested in reviving these modules ?

The raster format did not change between GRASS 5 and 6, so as long as
those modules do not access sites or vector maps "porting" to GRASS 6
usually just means copying it into the source tree and creating a new
Makefile for it (copy & adapt that from a nearby GRASS 6 raster module)

fwiw:
http://grass.osgeo.org/gdp/html_grass5/html/r.weight.html
  -- assign weights to category numbers, and overlay multiple maps. The
resulting output raster map layer depicts the combination of map layer
weights across a landscape. These values represent a hierarchy of
suitability for some user-defined purpose.

http://grass.osgeo.org/gdp/html_grass5/html/r.weight2.html
  -- r.weight2 is the non-interactive version of r.weight

http://grass.osgeo.org/gdp/html_grass5/html/r.weighted.cn.html
  -- The r.weighted.cn program is sensitive to the current window
settings. Thus the program can be used to generate a weighted CN map of
any sub-area within the full map layer.

http://grass.osgeo.org/gdp/html_grass5/html/r.combine.html
  -- r.combine accepts commands that are similar to those used for
boolean combinations (AND, OR, NOT) in order to overlay user-selected
groups of categories from different raster map layers.



I think a similar method (assigning weights to category numbers) can be
done with r.category, although that functionality is hardly ever used now
that we have real FP raster maps. (Perhaps that's how r.weight works, I
haven't looked.)

see also
 http://grass.osgeo.org/wiki/GRASS_Module_Porting_List#Raster_modules



Hamish



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