I made the following script to merge shape files of different format types (poly,line, points):

def main():    
    import arcpy
    from arcpy import env
    import globalpath
    import os
    env.workspace = globalpath.toolDataPath
    arcpy.env.overwriteOutput = True


    for dType in DataTypeL:
        matches = []

        for dirpath, dirnames, filenames in arcpy.da.Walk(dataPath+"\\UtilityDataFromZorgel",datatype="FeatureClass",type=Typei):
            for filename in filenames:       
                match = ( os.path.join(dirpath, filename))
                matches.append (match)
                counter = counter + 1 
        arcpy.Merge_management(matches, dataPath+"\\utilities"+Title)
        arcpy.AddMessage(str(counter)+" "+str(Typei)+" layers were merged into "+ str(filename))
    arcpy.AddWarning("Merging Utility Layers Failed")
if __name__ == "__main__":

I get the following error:

Traceback (most recent call last):
  File "C:\merger.py", line 30, in <module>
  File "C:\merger.py", line 25, in main
    arcpy.Merge_management(matches, dataPath+"\\utilities"+Title)
  File "c:\program files (x86)\arcgis\desktop10.1\arcpy\arcpy\management.py", line 3762, in Merge
    raise e
ExecuteError: ERROR 001156: Failed on input OID 0, could not write value 'Kanata' to output field TILE_ID
Failed to execute (Merge).

When I merge these files manually from arcmap it works, and fields are mapped as follows:

"STRUCT_TYP \"STRUCT_TYP\" true true false 18 Text 0 0 ,First,#,Allstream_hdwr_L,STRUCT_TYP,-1,-1,allstream_L,STRUCT_TYP,-1,-1,Allstream_lines_L,STRUCT_TYP,-1,-1,Allstream_text_L,STRUCT_TYP,-1,-1,Atria_lines_L,STRUCT_TYP,-1,-1,Atria_text_L,STRUCT_TYP,-1,-1,bell_L,STRUCT_TYP,-1,-1)

where STRUCT_TYP is a shared field.

please let me know how can I get around this error, and if it is indeed mapping the fields how can I do it in batched merging, or should I merge each file individually?


1 Answer 1


I got it to run on a directory full of parcels, PLSS, and annexations. The directory had a mix of shapefiles and file geodatabases. I defined the datapath differently, but otherwise changed nothing.

It failed on the 13th polygon feature class. The resulting shapefile had 62 fields and 44525 records. My failure was a type mismatch, so it was different than yours.

Try running on a subset of your input feature classes and add some print commands to tell you which feature class failed. You may have a field name or file name that is invalid in arcpy, but works when the feature class is inserted as a layer in ArcMap.

  • I'll try that and post what I find
    – Solaire
    May 20, 2015 at 11:55
  • and why did you get a type mismatch at that point I'm curious
    – Solaire
    May 20, 2015 at 12:00
  • adding error handlers shows that only polygons are giving me errors, i removed some of the shape files to see if the issue persists it appears that "TILE_ID" is a problematic field as the problem appears with different values other than "Kanata"
    – Solaire
    May 20, 2015 at 13:12
  • Is the "TILE_ID" field the same length (in characters) in all of your source files? If not, then rename one of your files with a wider "TILE_ID" field so that it is processed first.
    – jlcrawf0
    May 20, 2015 at 15:36
  • no it's not the same length, I could have swore its about text length, i was trying to recalculate the value for "TILE_ID" as str(!TILE_ID!)[:4]
    – Solaire
    May 20, 2015 at 15:38

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