Testing if two GDAL datasets are in same projection

Question

I'm attemping to write a function to test if a list of datasets are in the same projection. Naively, I thought I could test the text of WKTs, but that does not work in the following case:

'PROJCS["NAD_1983_UTM_Zone_14N",GEOGCS["NAD83",DATUM["North_American_Datum_1983", ...'

'PROJCS["NAD83 / UTM zone 14N",GEOGCS["NAD83",DATUM["North_American_Datum_1983", ...'

Even though the projections are identical, and the rest of the WKT is identical, the tags leading them are not which makes me wonder if there is a formal mechanism for testing the equality of projection systems.

I am programming with the GDAL extensions in Python.

Answer 1

To add to @Mike T's answer, GDAL/OSR SpatialReference object has a IsSame() function that can be used in Python GDAL like so:

from osgeo import osr

spref1 = osr.SpatialReference()
spref1.ImportFromEPSG(4326)

spref2 = osr.SpatialReference()
spref2.ImportFromEPSG(4269)

comparison = spref1.IsSame(spref2)

If the value of comparison is 1 then it is the same spatial reference. In the above example, it will return 0.

Answer 2

Try importing the WKT into an GDAL/OSR SpatialReference object, and compare the non-zero SRIDs. It is much simpler to compare two integers than to compare two text markups.

Look at this answer to Shapefile PRJ to PostGIS SRID lookup table? to get an idea how to use GDAL for this purpose.