Changing map symbology with arcpy?

Question

I've written a program that maps out a specific point file of interest. The program produces a map (clipped map attached below) but I can't figure out how to change the symbology to different colors. Is this possible? I've been looking through the arcpy.mapping library on ESRI and I haven't been able to find much on the subject.

if land_result == 1:                                                                                                                       
 with arcpy.da.SearchCursor(inFC, ['edited_nam', 'Field12']) as cursor:
  for x in cursor:
    print 'The %s %s contains tribal lands within its buffer zone' % (x[0], x[1])

  mxd = arcpy.mapping.MapDocument(r'P:/Python/topo_template.mxd')

  add_substation = arcpy.mapping.Layer(output_tribal_name)
  add_triballand = arcpy.mapping.Layer(triballands)

  df = arcpy.mapping.ListDataFrames(mxd, 'Data_Frame')[0]
  df.extent = add_substation.getExtent ()

  for df in arcpy.mapping.ListDataFrames(mxd):
    df.rotation = 0
    df.scale = 32000

  sub = arcpy.mapping.AddLayer(df, add_substation, 'AUTO_ARRANGE')
  wet = arcpy.mapping.AddLayer(df, add_triballand, 'AUTO_ARRANGE')

  north_arrow = arcpy.mapping.ListLayoutElements(mxd, 'MAPSURROUND_ELEMENT', 'North*')
  narrow = north_arrow[0]
  narrow.elementPositionX = 4.25
  narrow.elementPositionY = 1.25

  map_legend = arcpy.mapping.ListLayoutElements(mxd, 'LEGEND_ELEMENT', 'Map_L*')
  legend = map_legend[0]
  legend.elementPositionX = 0.5
  legend.elementPositionY = 1.33

  map_scale_bar = arcpy.mapping.ListLayoutElements(mxd, 'MAPSURROUND_ELEMENT', 'Scale*')
  scalebar = map_scale_bar[0]
  scalebar.elementPositionX = 4.25
  scalebar.elementPositionY = 0.33
  scalebar.elementWidth     = 3.75
  scalebar.elementHeight    = 0.3

  map_title = arcpy.mapping.ListLayoutElements(mxd, 'TEXT_ELEMENT', 'Map_T*')
  title = map_title[0]
  title.elementPositionX = 4.25
  title.elementPositionY = 10.75
  title.text = output + ' Wetland Buffer'

  map_data_frame = arcpy.mapping.ListLayoutElements(mxd, 'DATAFRAME_ELEMENT', 'Data_F*')
  dataframe = map_data_frame[0]
  dataframe.elementPositionX = 4.25
  dataframe.elementPositionY = 2.75
  dataframe.elementHeight = 7.5
  dataframe.elementWidth  = 7.5

  mpc_image = arcpy.mapping.ListLayoutElements(mxd, 'PICTURE_ELEMENT', 'MPC*')
  mpcimage = mpc_image[0]
  dataframe.elementpositionX = 8.0
  dataframe.elementpositionY = 1.55

  arcpy.mapping.ExportToPDF(mxd, r'P:/Python/' + output + 'topo_tlands.pdf')

  del mxd

Answer 1

To change an element's symbology you have to use the Apply Symbology from Layer tool. This means that you cannot directly specify the element's symbology from arcpy but you rather have to create a .lyr file and then apply it to the element using arcpy. The syntax of this tool in arcpy is the following:

ApplySymbologyFromLayer_management(in_layer, in_symbology_layer)

To create a .lyr file you have to manually change the symbology of an element in ArcMap and then right click on the layer > Save as Layer File... Having the .lyr file you can specify its path as the second parameter of the previously mentioned tool.

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Futhermore, the circle in your map has a blue border because it is selected. If you wanted to get rid of that border you could run the following line specifying your layer object to clear the selection:

arcpy.SelectLayerByAttribute_management(your_layer_object, 'CLEAR_SELECTION')