Hello All,
I have written a python module (using Python26) to perform some operations on rasters and use r.out.gdal at the end to export the resulting raster grid to a geoTiff.
grass.read_command(“r.out.gdal”, input=inGrid, output=outTif, flags=“c”, nodata=nv, type=‘Float32’)
The problem is that the DATUM and SPHEROID information are not being properly exported from the LOCATION. If I run the exact same r.out.gdal command from the GRASS GUI on the same raster, the DATUM and SPHEROID are fine. The EPSG code for the projection that I am using is 27700 (OSGB National Grid). (The same happens when using another set of data with projection code EPSG:3035)
My question is: are GRASS and python using different projection libraries and, if so, what do I need to do to make the python version of r.out.gdal pick up the correct projection??
gdalinfo output on the python-run command gives:
…
Coordinate System is:
PROJCS[“Transverse Mercator”,
GEOGCS[“airy”,
DATUM[“unknown”,
SPHEROID[“unnamed”,6377563.396,299.3249646000044]],
PRIMEM[“Greenwich”,0]
…
but the gdalinfo output from the GRASS-run r.out.gdal command gives:
…
Coordinate System is:
PROJCS[“Transverse Mercator”,
GEOGCS[“airy”,
DATUM[“OSGB-1936”,
SPHEROID[“Airy 1830”,6377563.396,299.3249646000044,
AUTHORITY[“EPSG”,“7001”]],
AUTHORITY[“EPSG”,“6277”]],
PRIMEM[“Greenwich”,0]
…
Thanks for your help.
Anne
Anne Brookes
Senior Analyst
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