[GRASSLIST:797] r.statistics

GRASS GRASS user
1

Dear list,

when I use r.statistiucs in GRASS-5.0.2 I get the following error
message:

"ERROR: This module currently only works for integer (CELL) maps"

I am using a category map as base map and a floating point map as cover.
This error does not appear when I use r.average with the same raster
maps.

Is there a bug in r.statistics? Or do I still have to assign category
values to one of the maps?

Ulrich

--
_______________________________________________

Ulrich Leopold MSc.

Dep. Phys. Geography and Soil Science
Inst. for Biodiversity and Ecosystem Dynamics
Faculty of Science
University of Amsterdam
Nieuwe Achtergracht 166
NL-1018 WV Amsterdam

Phone: +31-(0)20-525-7456 (7451 Sectretary)
Fax: +31-(0)20-525-7431
Email: uleopold@science.uva.nl
http://www.frw.uva.nl/soil/Welcome.html

2

Ulrich Leopold wrote:

when I use r.statistiucs in GRASS-5.0.2 I get the following error
message:

"ERROR: This module currently only works for integer (CELL) maps"

I am using a category map as base map and a floating point map as cover.
This error does not appear when I use r.average with the same raster
maps.

Is there a bug in r.statistics?

It's a limitation.

Or do I still have to assign category values to one of the maps?

The simplest solution is to quantise the cover map with r.mapcalc,
e.g.

  r.mapcalc 'foo.quant = int(foo * 1000)'

Choose a scale factor which is large enough to give a reasonable
resolution. However, larger scale factors will result in increased
memory usage and slower execution, particularly for larger maps.

--
Glynn Clements <glynn.clements@virgin.net>