readRAST6 problem - R-SIG-Geo

Tue, Apr 28, 2009 3:31 AM #

Hi!

I'm getting this message at reading a grass raster file:

rastdum <- readRAST6("nomdum",cat=F)
raster map/current region mismatch detected in components:
           cols            rows origin.northing  origin.easting
           TRUE            TRUE           FALSE            TRUE
set plugin=TRUE to override; continuing with plugin=FALSE
ERROR 6: SetColorTable() only supported for Byte or UInt16 bands in TIFF 
format.
/media/Transcend/Montseny/GrassData//carlos/A_TOTAL/.tmp/caminoccg/nomdum 
has GDAL driver GTiff
and has 94 rows and 116 columns

1. I don't think I have to worry about the ERROR 6:
2. But why is it stating a GTiff driver for reading a grass raster? Is 
there a previous conversion from raster to GTiff?

Thanks

Agus

Carlos Luis Camino Gonz?lez
Grupo Ecolog?a Del Paisaje
?rea de Biodiversidad
Centro Tecnol?gico Forestal de Catalu?a
Ctra. Sant Lloren? de Morunys, km. 2
Solsona (LLeida)
Tel 973481752
Fax. 973480431
http://todosig.awardspace.com/  Web de Sig y Teledetecci?n   ??en 
Construcci?n!!

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Roger Bivand

Tue, Apr 28, 2009 3:48 AM #

On Tue, 28 Apr 2009, Agustin Lobo wrote:

No, this message is conditional on your GRASS r.out.gdal version, recent 
versions support a flag to turn off colour table export to GTiff.

Yes, as you will see, your working region and the region of the raster 
differ. The plugin exports the raster in its own region, not the current 
region, while r.out.gdal respects the current region. If the two do not 
match, r.out.gdal/readGDAL are used with a temporary file rather than the 
plugin. To extract the raster in its own region, use execGRASS("g.region", 
parameters=list(rast="nomdum")) first, then the plugin region and the 
current region should be the same.

Hope this helps,

Roger

Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no

Agustin Lobo

Tue, Apr 28, 2009 4:18 AM #

In my case, I do not see the reason why the current region and the 
raster region should be
different. Everything is within a for() loop, in which I
set the region,
create a MASK,
create a raster with r.mapcalc (hence the same region than the current 
region)
import the raster to R

It's not critical for what I'm doing now (R calculates a textural 
statistics for small irregular windows)
but could be a problem if I had to bring back an R-modified SGDF to 
grass, right?

(btw, I never know if I can/have to CC to grass-stats about these 
issues, there is the cross-posting
problem)

Agus

Roger Bivand wrote:

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