Bulk Define Projection in ArcGIS

Occasionally I have a workspace (usually a file geodatabase) where I need to define the projection for all of the feature classes in the workspace. Here’s a simple script to do this.

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import arcpy

#Enter the full path to a workspace
ws = r"C:\path\to\myFGDB.gdb"
#Enter a WKID for a coordinate system
wkid=32100

arcpy.env.workspace = ws

sr = arcpy.SpatialReference(wkid)
fcs = arcpy.ListFeatureClasses()

for fc in fcs:
    arcpy.DefineProjection_management(fc, sr)

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