Python and ArcObjects- Stand Alone open MXD

Question

I wrote a Python function using comtypes to access ArcObjects to programmatically change the size of layer symbols in an MXD. The function works great in the Python window of ArcMap. However, I need to do this stand alone to do this for many MXD's.

Using arcpy I can open an MXD in memory like this:

mxd = arcpy.mapping.MapDocument(r'C:\some_folder\map.mxd)

I need to figure out how to do the above using ArcObjects (except return an instance of Application/IMxApplication). In my ArcObjects function, I am starting with a reference to the current open document. However, I cannot figure out how to do this without having a map document open.

I thought I could do something like this (using my own version of snippets):

import arcobjects
import comtypes.gen.esriFramework as esriFramework
import comtypes.gen.esriArcMap as esriArcMap
arcobjects.InitStandalone()
app = arcobjects.NewObj(esriArcMap.Application, esriFramework.IApplication) #this isn't doing the trick

And then calling app.OpenDocument() to point to the file path to actually open the MXD. This is not working and I do not know enough about initializing things in ArcObjects to know what I'm doing wrong. I know I cannot access anything from the AppROT to get a reference to the current running application because ArcMap/Catalog are not open.

In order to be able to call my function to set the symbol sizes, I need to pass in a reference to an IApplication instance (which I normally get this interface by using GetApp() or GetCurrentApp()). I cannot seem to find code samples for this anywhere. Does anyone know how to do this stand alone in Python?

Here is what I'm using to set the symbol sizes:

def setSymbolSize(pApp, layer_names=[], pointSize=12, lineWidth=1, autoSave=True):
 """sets the size/width of simple esri Marker or Line symbols
 Required:
 pApp -- open mxd instance, must be of type esriArcMapUI.IMxApplication
 Optional:
 layer_names -- list of layer names to set size of as they appear in TOC.
 pointSize -- size for all point layers specified. Default is 12
 lineWidth -- width for all line layers specified. Default is 1
 autoSave -- option to save document automatically after making changes.
 Default is True.
 """
 import comtypes.gen.esriDisplay as esriDisplay
 import comtypes.gen.esriArcMapUI as esriArcMapUI
 import comtypes.gen.esriCarto as esriCarto
 if isinstance(layer_names, (basestring)):
 layer_names = [layer_names]
 # defaults for point (shapeType 1) is 12, default for line (shapeType 3) is 2
 defaultSymbol = {1: esriDisplay.IMarkerSymbol,
 3: esriDisplay.ILineSymbol}
 # iterate through layer list
 for lyr in iterLayers(pApp):
 if lyr.Name in layer_names:
 # cast to esriCarto.IGeoFeatureLayer to get renderer
 flyr = CType(lyr, esriCarto.IFeatureLayer2)
 iGeo = CType(lyr, esriCarto.IGeoFeatureLayer)
 renderer = iGeo.Renderer
 # cast to simple renderer and then to simple symbol
 simple = CType(renderer, esriCarto.ISimpleRenderer).Symbol
 # cast to marker symbol interface and set size or width
 marker = CType(simple, defaultSymbol[flyr.ShapeType])
 if flyr.ShapeType == 1 and pointSize is not None:
 marker.Size = pointSize
 elif flyr.ShapeType == 3 and lineWidth is not None:
 marker.Width = lineWidth
 # refresh Map
 pDoc = pApp.Document
 pMxDoc = CType(pDoc, esriArcMapUI.IMxDocument)
 pMxDoc.UpdateContents()
 pMxDoc.ActiveView.Refresh()
 if autoSave in (True, 1):
 pApp.SaveDocument()
 return

Answer 1

Something like the following should work:

GetModule('esriCarto.olb')
import comtypes.gen.esriCarto as esriCarto
pMapDocument = CreateObject(esriCarto.MapDocument, esriCarto.IMapDocument)
pMapDocument.Open(path)
#Do stuff
pMapDocument.Save()

• crmackey: Thanks! That is way too easy, I was not aware of the MapDocument class from esriCarto.