Changing Symbology in Python

Question

Hi So I am working a project to create these maps and I am trying to get symbology to change but I cant 

import arcpyfrom arcpy import envarcpy.env.overwriteOutput = True#Set File workspacefile_workspace = 'N:\GIS\Projects\AA_Leith_Hawkins_TestBed\Search_Cursor\Search_Cursor.gdb'env.workspace = file_workspace#buffer set upHoldings = 'N:\GIS\Projects\AA_Leith_Hawkins_TestBed\Search_Cursor\Search_Cursor.gdb\Data\Holdings'distances = [1000, 4000]unit = "Meters"#Make a feature layerarcpy.MakeFeatureLayer_management(Holdings,'Holdings_Layer')#searchcursor for evey row in datasetwith arcpy.da.SearchCursor(Holdings, ['Holding_Reference_Number'])as Holdings_Ref_cursor:    for row in Holdings_Ref_cursor:        print row[0]        query = "Holding_Reference_Number = " + str(row[0])        print query        File_output = file_workspace+ '\' 'Buffer_'+str(row[0])        #print File_output        #Select Feature using the reference number from holdings layer        arcpy.SelectLayerByAttribute_management('Holdings_Layer', 'NEW_SELECTION',"Holding_Reference_Number = " + str(row[0]))        # Export holding to geodatabase        Holding_Boundary = file_workspace+ '\' 'Holding_'+str(row[0])        arcpy.management.CopyFeatures('Holdings_Layer', Holding_Boundary)        #Mutliple ring Buffer using Selected Features        arcpy.MultipleRingBuffer_analysis('Holdings_Layer', File_output, distances, unit, "", "ALL")        arcpy.MakeFeatureLayer_management(File_output, 'Buffer_Layer')       #arcpy.Buffer_analysis("Holdings_Layer", ofc, var_Buffer, "FULL", "ROUND", "ALL", "")        print 'Buffer complete'        #Intersect Features        Intersect_out_features = file_workspace+ '\' 'Intersect_'+str(row[0])        arcpy.Intersect_analysis([Holdings,File_output],Intersect_out_features, "", "", "INPUT")        print "intersect Complete"        #delete Fields        Drop_Fields = ['FID_Holdings','Holding_Reference_Number','Holding_Location_Address','Local_Land_Services_Region_Id',                      'Local_Land_Services_Region_Name', 'RLPB_Board_Name', 'Property_Identification_Code','Occupier_Id',                      'Occupier_Full_Name','Occupier_Mailing_Address','Occupier_Home_Phone','Occupier_Mobile_Phone',                       'Occupier_Email_Address', 'Total_Area', 'Is_Rateable_Indicator','Rateable_Area','Nominal_Notional_Carrying_Cap',                       'FID_Buffer_108050022']        arcpy.DeleteField_management(Intersect_out_features,Drop_Fields)        #Export to Excel        arcpy.MakeFeatureLayer_management(Intersect_out_features, 'Intersect_Layer')        Intersect_Selection_Excel = 'distance = 1000'        print Intersect_Selection_Excel        arcpy.SelectLayerByAttribute_management('Intersect_Layer', 'NEW_SELECTION', Intersect_Selection_Excel)        Excel_Output = 'N:\GIS\Projects\AA_Leith_Hawkins_TestBed\Search_Cursor\'        Excel_Location = Excel_Output + '\' +str(row[0])+'.xls'        print Excel_Location        arcpy.TableToExcel_conversion('Intersect_Layer', Excel_Location)        #arcpy.SelectLayerByAttribute_management('Intersect_Layer', 'CLEAR_SELECTION')        #print Png_output        #test = arcpy.MakeFeatureLayer_management(File_output, 'Buffer_Layer')        #arcpy.ApplySymbologyFromLayer_management('Buffer_Layer', 'C:\Database_connections\assesment_Model_lyr\Buffer.lyr')        #arcpy.ApplySymbologyFromLayer_management('Holdings_Layer',         #                                        'C:\Database_connections\assesment_Model_lyr\Holding.lyr')        #arcpy.ApplySymbologyFromLayer_management('Intersect_Layer',         #                                        'C:\Database_connections\assesment_Model_lyr\Intersect.lyr')        #add Layers to the Map        mxd = arcpy.mapping.MapDocument('N:\GIS\Projects\AA_Leith_Hawkins_TestBed\Search_Cursor\Search_Cursor_mxd.mxd')        df = arcpy.mapping.ListDataFrames(mxd, "Layers")[0]        addLayer = arcpy.mapping.Layer(File_output)        addLayer2 = arcpy.mapping.Layer(Holding_Boundary)        addLayer3 = arcpy.mapping.Layer(Intersect_out_features)        arcpy.mapping.AddLayer(df, addLayer, "TOP")        print addLayer        arcpy.mapping.AddLayer(df, addLayer2, "TOP")        print addLayer2        arcpy.mapping.AddLayer(df, addLayer3, "TOP")        print addLayer3        arcpy.RefreshActiveView()        #change Symbology        arcpy.ApplySymbologyFromLayer_management('Buffer_Layer', 'C:\Database_connections\assesment_Model_lyr\Buffer.lyr')        arcpy.ApplySymbologyFromLayer_management('Holdings_Layer', 'C:\Database_connections\assesment_Model_lyr\Holding.lyr')        arcpy.ApplySymbologyFromLayer_management('Intersect_Layer', 'C:\Database_connections\assesment_Model_lyr\Intersect.lyr')        arcpy.RefreshActiveView()        #zoom to layer        print df        lyr = arcpy.mapping.ListLayers(mxd, '', df)[2]        print lyr.name        extent = lyr.getExtent()        print extent        df.extent = extent        #Export Map to PNG File        Png_output = "N:\GIS\Projects\AA_Leith_Hawkins_TestBed\" + str(row[0]) + '.png'        arcpy.mapping.ExportToPNG(mxd,Png_output)        print 'Map Created'        del mxd‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍


I cant work out where I need to call the Change symbology from ive had a look through the syntax guide but I think I must be a bit slow

Should I be calling the layer file or the layers I am adding to the Dataframe ??

LukeWebb · Accepted Answer

Hi, Your script:

1) Creates the layer with default symbology

2) Adds it to the map.

3) Changes the symbology of the original layer. (Not the one that is now in the map)

4) Exports the map.

You need to either:

a) find reference to the layer in the map after you have added it and change the symbology here.

OR

b) Change the symnbology of the layer, and then add to the map.