How to find a datasets spatial reference and apply it to another dataset?

Question

I'm struggling to use the describe function to find the spatial reference of a given shapefile and then apply it to another shapefile which has been copied to a projected folder.

I'm relatively new to using python so I apologize if my code attempt is dismal.

This is where I'm at:

import arcpy

data = arcpy.GetParameterAsText(0)
targetProjection = arcpy.GetParameterAsText(1)
projected = arcpy.GetParameterAsText(2)

# Create an error class
class NoExist(Exception):
    pass

try:

 # copy dataset to projected dataset folder
    arcpy.copyFeatures_management(data, projected)

 # describe the spatial reference of the dataset in the target projection folder
    desc = arcpy.Describe(targetProjection)

    # obtain the spatial reference
    spatialRef = desc.spatialReference

I think I've worked out how to find the target projection but am unsure of how I apply that to my other dataset.

Answer 1

Have a look at the Define Projection tool and its code usage. As @dslamb points out, this method is used to assign a projection if one has not already been assigned, or if you wish to reassign a different projection. Once you have the desired SpatialReference object, you could do something like the following:

arcpy.DefineProjection_management(projected, spatialRef)

Another option, if you want to project the data from one coordinate system to another, is to use the Project tool.