Arcpy's replaceDataSource Error

Question

I've checked the other answers here and none of the answers worked for me...

It's a "simple" matter of finding a layer by name in a map and changing it's datasource.

Here's my script:

    #-- New Source
    newSource = os.path.join(currDir, lyrZones + "_Dep" + dirNum + ".shp")

    #-- Validation
    if arcpy.Exists(newSource):
        print "The new source exists!"
    else:
        print "Not found!"

    #-- Find the layer and change its source            
    for lyr in arcpy.mapping.ListLayers(mxd):
        if lyr.name == lyrZones:
            print "Layer found!"
            print layers.dataSource
            print "  Replacing source..."
            lyr.replaceDataSource(currDir, "SHAPEFILE_WORKSPACE", newSource)
            print lyr.dataSource

I run it from a python script outside ArcGIS.

You can see that the source exists, the layer is found, I can access it's datasource by printing it, but the lyr.replaceDataSource causes an error (Unexpected error... doesn't help much...)

I've been working at it for 4-5 hours now and I'm short of solutions to try. Any idea what can cause the crash?

Answer 1

I know this is pretty old, but I just encountered this same issue and was surprised by the lack of solutions out there. The solution is so simple, but you'd have no way of knowing it based on ESRI's practically non-existent help:

Don't include the shapefile extension. ...That's it.

newSource = os.path.join(currDir, lyrZones + "_Dep" + dirNum + ".shp")

Should read:

newSource = os.path.join(currDir, '{}_Dep{}'.format(lyrZones, dirNum))

Answer 2

I don't know if this helps you or not but I've encountered this error trying to switch SDE data sources for a layer. What I found is that when I'd run from PyScripter, it would spool up a 64-bit python.exe process. I'd get the ValueError. If I forced the script to run using the 32-bit python.exe via Command Prompt, I wouldn't get the error. I don't know if that would help your issue or not but it's worth a shot!

Answer 3

Most info on this is here. But to solve this I went into the python window within ArcCatalog to check on the ESRI definitions of each parameter in the .replaceDataSource function.

.replaceDataSource(workspace, workspace_type, dataset_name)

workspace = workspace of new data source

workspace_type = the actual workspace type listed in the replace datasource section of the linked help.

dataset_name = file name without the file type (IE: .shp), not the dataset name in the table of contents. No need for the directory in front of it either.

Answer 4

Fun with debugging! Try this:

for lyr in arcpy.mapping.ListLayers(mxd):
    if lyr.name == lyrZones:
        if lyr.supports("DATASOURCE"):
            print lyr.dataSource
            print currDir
            print newSource
            lyr.replaceDataSource(currDir, "SHAPEFILE_WORKSPACE", newSource, TRUE)
            print "Did we crash yet?"
            print lyr.dataSource
        else:
            print "Layer isn't supported!"