I have a geologic map with 230 geological units. Each unit has its own color, marker, ecc... It is possible to apply a scheme for each geological unit using a python script? Because I have an xml files that for each unit define color, border, marker ecc...
Thank you!
I don't know about from an xml file but if your willing to create a lyr file you could use Setting output symbology in scripts—Help | ArcGIS for Desktop
I don't think arcpy has the capability to change symbology (other than importing from an existing layer file).
You can use the comtypes module to access ArcObjects from Python. That will allow you to control symbology.
Have a look here for more information on ArcObjects and Python.
The snippits.py has some useful examples.
You will also probably need to look over the ArcObject help and Object Model Diagrams. Carto is the one which will have the symbology.
Ben