Updating raster of mxd file using ArcPy?

Question

Using ArcGIS 10 wanted to update the raster file in a mxd file using python. for example, i created a.mxd which contains b.tif file in it. now, i obtained c.tif and want to update the a.mxd, i.e. want to delete b.tif and add c.tif, or overwrite b.tif with c.tif

import arcpy
mxd = arcpy.mapping.MapDocument(r"C:\data\a.mxd")
df = arcpy.mapping.ListDataFrames(mxd)[0]
updateLyr = arcpy.mapping.ListLayers(mxd)[0]
sourceLyr = arcpy.mapping.Layer(arcpy.Raster(r"C:\data\c.tif"))
arcpy.mapping.UpdateLayer(df, updateLyr, sourceLyr, True)
del mxd

i started as above, but i think that i am not getting most of the things correctly.

Answer 1

I think you want replaceDataSource instead of UpdateLayer. Update uses a template, the sourceLyr, and applies its properties (data path, symbology, etc.) to the layer-to-be-updated whereas you only want to change the data path/filename.

See Updating and fixing data sources with arcpy.mapping in the Esri docs for more detail, and Changing data source path involving feature dataset in *.lyr files using ArcPy? here on GIS.se for some quirky behaviour to be aware of.

Answer 2

Create a layer file consisting of your new tif, named 'c.lyr' and place it in the same directory (i.e. c:\data\c.lyr) Then run this inside the map document:

import arcpy
mxd = arcpy.mapping.MapDocument("CURRENT")
for df in arcpy.mapping.ListDataFrames(mxd):
 for refLayer in arcpy.mapping.ListLayers(mxd, "*b.tif", df):
 mosaic = arcpy.mapping.Layer(u'C:\\data\\c.lyr')
 arcpy.mapping.InsertLayer(df, refLayer, mosaic, "BEFORE")
 mosaic.visible = refLayer.visible
 mosaic.brightness = refLayer.brightness
 mosaic.contrast = refLayer.contrast
 mosaic.transparency = refLayer.transparency
 mosaic.name = refLayer.name
 arcpy.mapping.RemoveLayer(df, refLayer)
arcpy.RefreshActiveView()
arcpy.RefreshTOC()
del mxd, df
try:
 del refLayer, mosaic
except:
 pass
finally:
 print u'TIF updated!'

Or if you prefer a function:

def UpdateTIF(mxd, old, new):
#mxd: path to mxd to update
#old: wildcard matching pattern for the old source
#new: layer file referencing new source
 import arcpy
 mxd = arcpy.mapping.MapDocument(mxd)
 for df in arcpy.mapping.ListDataFrames(mxd):
 for refLayer in arcpy.mapping.ListLayers(mxd, old, df):
 mosaic = arcpy.mapping.Layer(new)
 arcpy.mapping.InsertLayer(df, refLayer, mosaic, "BEFORE")
 mosaic.visible = refLayer.visible
 mosaic.brightness = refLayer.brightness
 mosaic.contrast = refLayer.contrast
 mosaic.transparency = refLayer.transparency
 mosaic.name = refLayer.name
 arcpy.mapping.RemoveLayer(df, refLayer)
 del mxd, df
 try:
 del refLayer, mosaic
 except:
 pass
 finally:
 print u'TIF updated!'

Execute this with a call like:

UpdateTIF('C:\\data\\a.mxd', '*b.tif', 'C:\\data\\c.lyr')