I have a raster image that has a custom projection system. I used the following code to retrieve the projection information from the raster and turn it into an ArcGIS recognized PCS following this example...

import arcpy
from osgeo import gdal

raster_path = r"\\tiff_inputs\tiff_UTM_inputs\amz_jurisdiction_UTM20.tif"
in_ds = gdal.Open(raster_path)
projection = in_ds.GetProjection()
pcs = arcpy.SpatialReference(text=projection)

Here is the projection string when printed to the console...

'PROJCS["Brasil, Zona UTM 20, hemisf\udce9rio sul",GEOGCS["br_utm20sad_s",DATUM["South American 1969",SPHEROID["International 1967 (truncated)",6378160,298.24999999573],TOWGS84[-67.35,3.88,-38.22,0,0,0,0]],PRIMEM["Greenwich",0],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",-63],PARAMETER["scale_factor",0.9996],PARAMETER["false_easting",500000],PARAMETER["false_northing",10000000],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH]]'

However when I input this projection string into arcpy.SpatialReference I receive the following error:

ValueError: SpatialReference: Spatial reference string is invalid.

I cannot use the display name of the coordinate system as an input either because it is not recognized by arcpy.

How can I reformat the gdal projection string to be valid parameter for arcpy.SpatialReference?

2 Answers 2


Try creating an osr.SpatialReference() object from the GDAL WKT, then using MorphToESRI() to make any WKT it spits out ESRI-compatible.

Should look something like this:

from osgeo import osr

gdal_wkt = in_ds.GetProjection()
gdal_srs = osr.SpatialReference()
esri_wkt = gdal_srs.ExportToWkt()
esri_srs = arcpy.SpatialReference(text=esri_wkt)

Python docs: https://gdal.org/api/python/osgeo.osr.html#osgeo.osr.SpatialReference.MorphToESRI

C++ docs with a better description: https://gdal.org/doxygen/classOGRSpatialReference.html#aac948450b15fa3d8814ab440b9f705b7

  • Thanks for your suggestion. It appears that my wkt is not valid. I received an error TypeError: not a string when running gdal_srs.ImportFromWkt(gdal_wkt) using the projection string that I provided in the post. What do you suspect could be the issue?
    – ESimonson
    Commented Dec 7, 2023 at 16:14
  • Hmm, well what does type(gdal_wkt) give? If it's None then maybe you're trying a raster with no projection defined, or perhaps gdal is already giving back a SpatialReference?
    – mikewatt
    Commented Dec 7, 2023 at 18:05
  • 1
    I used encoding and decoding and this fixed my issues with the projection string. gdal_wkt = in_ds.GetProjection().encode('utf-8', 'backslashreplace').decode('utf-8')
    – ESimonson
    Commented Dec 11, 2023 at 15:00

While I am not sure why your projection isn't being recognised by ArcGIS Pro, the closest projection to the one you have provided looks like SIRGAS_2000_Brazil_Mercator. Try reprojecting your raster into that via ArcGIS Pro.

enter image description here

You can access the spatial reference in arcpy by using the following code:

pcs = arcpy.SpatialReference('SIRGAS_2000_Brazil_Mercator')
  • Hi Angus, I am trying to automate this part of the process and use the spatial reference at a later stage.
    – ESimonson
    Commented Dec 6, 2023 at 21:02

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