[GRASS-user] g.region usage in python for overriding N, S, E, W values

GRASS GRASS user
,
1

Hi,
I want to change North, East, South and West extent values of a raster map using python. In GUI I’ve used g.region function like this:

g.region -g -a rast=band1_2005_etm@PERMANENT n=4256115 s=4045185 e=831315 w=601785
n=4256115
s=4045185
w=601785
e=831315

As you see what I got is what I set. But I couldn’t do the same in python:

def loadMap(inputMapPath, outBandName):
mapLoaded = grass.run_command(‘r.in.gdal’, input=inputMapPath, output=outBandName, flags=‘o’, overwrite=True)
if(mapLoaded == 0):
print "Map Loaded From " + inputMapPath + " to " + outBandName
else:
print "ERROR: Map Loaded >From " + inputMapPath + " to " + outBandName
regionizeMap(outBandName)
print “”

def regionizeMap(bandName):
mapRegionized = grass.run_command(‘g.region’, rast=bandName, n=4256115, s=4045185, e=831315, w=601785, flags=‘a’, overwrite=True)
if(mapRegionized == 0):
print "Map Regionized: " + bandName
else:
print "ERROR: Map Regionized: " + bandName
print “”

def showRegionInfo(bandName):
r = grass.read_command(‘g.region’, rast=bandName, flags=‘g’, verbose=True)
print bandName
print r
print “”

The output is:

Map Loaded From D:\gis\data\l71175034_03420050627_b10histeqmatched.tif to band1_2005_etm
Map Regionized: band1_2005_etm

band1_2005_etm
n=4257015
s=4043385
w=601785
e=844215

You can see the differnce here, I set east to 831315 but what i got is 844215. What can I do the achieve same result with GUI?
Thanks in advance.

2

Hi,

you should probably use r.region [1], not g.region [2]:
g.region rast=... sets the computational region to match the raster map
r.region map=... sets the boundary of a raster map

Regards,
Anna

[1] http://grass.osgeo.org/grass64/manuals/r.region.html
[2] http://grass.osgeo.org/grass64/manuals/g.region.html

On Tue, Jan 15, 2013 at 1:53 AM, Gökçen Güner <gokcenguner@gmail.com> wrote:

Hi,
I want to change North, East, South and West extent values of a raster map
using python. In GUI I've used g.region function like this:

g.region -g -a rast=band1_2005_etm@PERMANENT n=4256115 s=4045185 e=831315
w=601785
n=4256115
s=4045185
w=601785
e=831315

As you see what I got is what I set. But I couldn't do the same in python:

def loadMap(inputMapPath, outBandName):
    mapLoaded = grass.run_command('r.in.gdal', input=inputMapPath,
output=outBandName, flags='o', overwrite=True)
    if(mapLoaded == 0):
        print "Map Loaded From " + inputMapPath + " to " + outBandName
    else:
        print "ERROR: Map Loaded From " + inputMapPath + " to " +
outBandName
    regionizeMap(outBandName)
    print ""

def regionizeMap(bandName):
    mapRegionized = grass.run_command('g.region', rast=bandName, n=4256115,
s=4045185, e=831315, w=601785, flags='a', overwrite=True)
    if(mapRegionized == 0):
        print "Map Regionized: " + bandName
    else:
        print "ERROR: Map Regionized: " + bandName
    print ""

def showRegionInfo(bandName):
    r = grass.read_command('g.region', rast=bandName, flags='g',
verbose=True)
    print bandName
    print r
    print ""

The output is:

Map Loaded From D:\gis\data\l71175034_03420050627_b10histeqmatched.tif to
band1_2005_etm
Map Regionized: band1_2005_etm

band1_2005_etm
n=4257015
s=4043385
w=601785
e=844215

You can see the differnce here, I set east to 831315 but what i got is
844215. What can I do the achieve same result with GUI?
Thanks in advance.

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