Adding Shapefile with Symbology from Layer File to ArcMap MXD using ArcPy?

Question

I have a Shapefile:

• C:\DATA\points.shp

A layer file:

• C:\SYMBOLOGY\symbology.lyr

And a map document:

• C:\MAPS\map.mxd

How can I add points.shp to map.mxd with the properties of symbology.lyr all using python?

Answer 1

I just tested this and it worked!

The layer file that I added, and then changed the data source of, was saved from a layer called dummy that pointed at a dummy.shp file.

import arcpy

mxd = arcpy.mapping.MapDocument("C:\\MAPS\\map.mxd")
df = arcpy.mapping.ListDataFrames(mxd,"Layers")[0]

addLayer = arcpy.mapping.Layer("C:\\SYMBOLOGY\\symbology.lyr")
arcpy.mapping.AddLayer(df, addLayer)
lyr = arcpy.mapping.ListLayers(mxd,"dummy",df)[0]

print lyr.name
print lyr.dataSource

lyr.replaceDataSource("C:\\DATA\\", "SHAPEFILE_WORKSPACE", "points")
lyr.name = "points"

print lyr.dataSource
print lyr.name

mxd.saveACopy("C:\\MAPS\\map2.mxd")

Answer 2

I haven't tested this out, but the easiest way should be to simply rename (or copy) symbology.lyr to points.lyr (the same basename as your shapefile). Generally speaking, when you load a shapefile into ArcMap that has a similarly name Layer file, the symbology of the layer "follows" the raw data (shapefile) and is applied on load.