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Issues with ArcPy SpatialReference Class

Question asked by mbrehm1991 on Apr 27, 2016
Latest reply on May 1, 2016 by bixb0012

     I am attempting to write a Python script that uses a general reference map of the NAD 1983 UTM Zones to automate the selection of an appropriate map projection for a specific area. I have completed the script up until the point at which I need to create a SpatialReference object that contains the appropriate projection. I have been getting a 999999 general runtime error whenever I try to assign the SpatialReference object the value of "NAD 1983 UTM Zone 9N" or lower, but past "NAD 1983 UTM Zone 10N", it works.


     This screenshot is the result of a test script in which I import ArcPy, and then try to initialize a SpatialReference object with the respective values mentioned above. In the second run, I printed the SpatialReference object's name in order to test to make sure that the value was assigned correctly. Am I missing something here, or is this a known issue with assigning the names of projections to SpatialReference objects? I would otherwise use the WKID for the projection, but the reference map that I am using only contains a field for the name of the projection.


Edit: I am using general reference maps for both the NAD 1983 UTM Zones as well as the USA State Plane Zones NAD83 in order to find an appropriate projection for an input dataset. I first find the centroid of the dataset, and then select by location from the reference projection maps. From the responses here and my own testing, it seems as if trying to assign SpatialReference objects the projections by name does not work for certain types of projections. Namely, the NAD 1983 UTM Zone 1-9 projections. I have also yet to find a U.S. State Plane projection in which the SpatialReference object does not give an error when attempting to assign the projection by name. The solution seems to be to assign the SpatialReference object by WKID. but this could be quite cumbersome if the assignment of projection WKIDs does not follow an intuitive pattern and you're working with hundreds of reference projections.