Different CRS equality comparisons can yield different results

[Ariana-B]

It is possible to have two CRS objects for which crs1 == crs2 is True, but whose string representations, and therefore hashes, are not equal. I would expect object equality and hash equality to be in alignment, or that there be some sort of normalisation done at initialisation.

Example:

crs1 = CRS('PROJCS["WGS 84 / UTM zone 53S",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"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",135],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],AUTHORITY["EPSG","32753"]]')

crs2 = CRS('PROJCRS["WGS 84 / UTM zone 53S",BASEGEOGCRS["WGS 84",DATUM["World Geodetic System 1984",ELLIPSOID["WGS 84",6378137,298.257223563,LENGTHUNIT["metre",1]]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],ID["EPSG",4326]],CONVERSION["UTM zone 53S",METHOD["Transverse Mercator",ID["EPSG",9807]],PARAMETER["Latitude of natural origin",0,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8801]],PARAMETER["Longitude of natural origin",135,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8802]],PARAMETER["Scale factor at natural origin",0.9996,SCALEUNIT["unity",1],ID["EPSG",8805]],PARAMETER["False easting",500000,LENGTHUNIT["metre",1],ID["EPSG",8806]],PARAMETER["False northing",10000000,LENGTHUNIT["metre",1],ID["EPSG",8807]]],CS[Cartesian,2],AXIS["easting",east,ORDER[1],LENGTHUNIT["metre",1]],AXIS["northing",north,ORDER[2],LENGTHUNIT["metre",1]],ID["EPSG",32753]]')

crs1 == crs2
>>> True

hash(crs1) == hash(crs2)
>>> False

hash(CRS(crs1.to_wkt())) == hash(CRS(crs2.to_wkt()))
>>> True

[snowman2]

pyproj4/pyproj#305

>>> from pyproj import CRS
>>> crs1 = CRS('PROJCS["WGS 84 / UTM zone 53S",GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUT\
HORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","43\
26"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",135],PARAMETER["scale_factor",0.9996],PARAMETE\
R["false_easting",500000],PARAMETER["false_northing",10000000],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH],A\
UTHORITY["EPSG","32753"]]')
... 
... crs2 = CRS('PROJCRS["WGS 84 / UTM zone 53S",BASEGEOGCRS["WGS 84",DATUM["World Geodetic System 1984",ELLIPSOID["WGS 84",6378137,298.257223563,LENG\
THUNIT["metre",1]]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],ID["EPSG",4326]],CONVERSION["UTM zone 53S",METHOD["Transverse Mercat\
or",ID["EPSG",9807]],PARAMETER["Latitude of natural origin",0,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8801]],PARAMETER["Longitude of natural\
 origin",135,ANGLEUNIT["degree",0.0174532925199433],ID["EPSG",8802]],PARAMETER["Scale factor at natural origin",0.9996,SCALEUNIT["unity",1],ID["EPSG"\
,8805]],PARAMETER["False easting",500000,LENGTHUNIT["metre",1],ID["EPSG",8806]],PARAMETER["False northing",10000000,LENGTHUNIT["metre",1],ID["EPSG",8\
807]]],CS[Cartesian,2],AXIS["easting",east,ORDER[1],LENGTHUNIT["metre",1]],AXIS["northing",north,ORDER[2],LENGTHUNIT["metre",1]],ID["EPSG",32753]]')
... 
>>> crs1.is_exact_same(crs2)
True
>>> hash(crs1) == hash(crs2)
True

[Kirill888]

odc.crs.CRS class is a thin, caching wrapper around pyproj.crs.CRS, we should probably just derive from it to be honest instead of "wrapping" it. Quickest fix is to use self._crs instead of str for hashing here:

odc-geo/odc/geo/crs.py

Lines 244 to 245 in 210ae22

	def __hash__(self) -> int:
	return hash(self._str)