OSR Python testSR.ImportFromEPSG(4326) returns empty spatial reference

Question

This is empty using Python .ImportFromEPSG(4326):

from osgeo import osr
#this fails:
testSR = osr.SpatialReference()
testSR.ImportFromEPSG(4326)
print testSR.ExportToPrettyWkt()
#why did the import from EPSG fail above?
testSR.SetWellKnownGeogCS("WGS84")
print testSR.ExportToPrettyWkt()
GEOGCS["WGS 84",
DATUM["WGS_1984", and so on...

• R.K.: Do you need to get the list using Python? Or would just getting the list work?
• R.K.: What version of ogr are you using?
• Dave: help(osr) Help on module osr: NAME osr - # import osgeo.osr as a convenience FILE c:\python27\arcgis10.1\lib\site-packages\osr.py
• Jay Laura: testSR.ImportFromEPSG('4326')? Do you need to pass a str instead of an int? - Also, make sure to go back and accept some answers to your other questions.
• user10353: Make sure GDAL_DATA is set to the proper location. It may be that the EPSG import is failing because it can't find the files.

Answer 1

First, the real error was skipped, since ImportFromEPSG returned a non-zero error code:

from osgeo import osr
testSR = osr.SpatialReference()
res = testSR.ImportFromEPSG(4326)
if res != 0:
 raise RuntimeError(repr(res) + ': could not import from EPSG')
print testSR.ExportToPrettyWkt()

Now the cause. GDAL needs an environment variable GDAL_DATA to find and use projection info. If it is not available, then some things stop working. The SRID look-up codes are in GDAL_DATA, for instance. Check if you have it:

import os
'GDAL_DATA' in os.environ

if False, it should be added to either your system's environment variables, or you can add it in run-time:

if 'GDAL_DATA' not in os.environ:
 os.environ['GDAL_DATA'] = r'/path/to/gdal_data'

• Dima Chubarov: If you set GDAL_DATA at run-time, you need to do that before you import osr and gdal
• RutgerH: also, what is the difference between GDAL_PATH and GDAL_DATA
• RutgerH: Very helpful, my path on Ubuntu is /usr/share/gdal/2.1
• Mike T: @RutgerH you've found a typo (there is no such thing as "GDAL_PATH"), all fixed, thanks!
• Jane: Anyway I had RuntimeError: 7: could not import from EPSG... and False when checking if 'GDAL_DATA' in os.environ. Although I specified os.environ['GDAL_DATA'] = r'/usr/share/gdal/2.2/' What's wrong?

Answer 2

You'll have to define test1 first

from osgeo import osr
test1 = osr.SpatialReference() #define test1
test1.ImportFromEPSG(4326)
print test1.ExportToPrettyWkt()

Only then can you call the ExportToPrettyWkt() function. Which should result in the following output:

GEOGCS["WGS 84",
 DATUM["WGS_1984",
 SPHEROID["WGS 84",6378137,298.257223563,
 AUTHORITY["EPSG","7030"]],
 AUTHORITY["EPSG","6326"]],
 PRIMEM["Greenwich",0,
 AUTHORITY["EPSG","8901"]],
 UNIT["degree",0.0174532925199433,
 AUTHORITY["EPSG","9122"]],
 AUTHORITY["EPSG","4326"]]

• Dave: This returns an empty spatial reference: import osr testSR = osr.SpatialReference() testSR.ImportFromEPSG(4326) print testSR.ExportToPrettyWkt()
• R.K.: You mean the print statement does not print anything for you?
• Dave: Correct. testSR.ImportFromEPSG(4326); txtTest = testSR.ExportToPrettyWkt(); len(txtTest) is zero while testSR.SetWellKnownGeogCS("WGS84"); txtTest = testSR.ExportToPrettyWkt() returns a string of 357 chars
• R.K.: What is your question btw? Now I'm confused. Is it to fix the error or to get the list of ESPG values? Where can I get a list of EPSG values for common spatial references? Also, how did you install your osr and what version are you using?
• Dave: testSR.ImportFromEPSG(4326) returns an empty spatial reference osr is from: c:\python27\arcgis10.1\lib\site-packages\osr.py