topic Re: Field mapping syntax (python) in Geoprocessing Questions

Field mapping syntax (python)

ChrisMathers — Thu, 22 Apr 2010 14:04:49 GMT

Ok so what is the syntax for field mapping? In tools that require fields to be mapped I have figured out what most of each field needs to be, but not all of it. In this example from a Spatial Join this is one field:

A1RENUM 'A1RENUM' true true false 15 Text 0 0 ,First,#,C:\\GIS Projects\\CRW\\TrakIt_Source_RS.gdb\\Target_Data\\parce_test_FeatureToPoint.shp,A1RENUM,-1,-1

The syntax is:
NewFieldName 'NewFieldAlias' ? ? ? NewFieldLength NewFieldType ? ?, MergeRule, MergeDelimeter, SourcePath, SourceFieldName, ? , ?

NewField is the field in the table created by the tool. MergeDelimeter is # if you arent using the Join merge rule. What I want to know is what True True False, 0 0 , and -1,-1 are doing.

Re: Field mapping syntax (python)

SimonWillis — Wed, 23 Jun 2010 19:48:35 GMT

A little late but here I found some good info:

http://forums.esri.com/Thread.asp?c=93&f=1729&t=207100#678774

Re: Field mapping syntax (python)

ChrisMathers — Thu, 24 Jun 2010 11:49:28 GMT

HA! Thanks. Its funny that someone else asked the exact same thing I did.

Re: Field mapping syntax (python)

SimonWillis — Thu, 24 Jun 2010 18:16:58 GMT

Did you ever get it to work? I have also been using the fieldmapping/fieldmap object and I keep bombing in pywin... I even took a couple of steps back to make the fieldmapping example work in arctoolbox - Merge (Data Management).
It's similar to arcgis10 arcpy fieldmapping example:
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/FieldMappings/000v0000008q000000/
I still can't get it to work!

Re: Field mapping syntax (python)

ChrisMathers — Thu, 24 Jun 2010 20:00:03 GMT

I ended up using the tool in catalog to set it all up. I just went back and did a find-replace to change the file paths. Much quicker than typing all of it. I have a spatial join in one script that is 20685 characters long, most all of it is field mapping. I wrote papers shorter than that in college.

Re: Field mapping syntax (python)

SimonWillis — Tue, 06 Jul 2010 17:07:22 GMT

I finally got the fieldmapping object to work and it works great to append a shp to SDE in pythonwin2.5 but attached as a script in arctoolbox it bombs out and complains about:

PYTHON ERRORS:
Traceback info:
File "C:\temp\SplitProcessImport063010.py", line 266, in ?
    import2SDE(UpdWorkspace, outputUpdFC)

Error Info:
(-2147467259, 'Unspecified error', None, None)
Geoprocessing ERRORS:
Failed to execute. Parameters are not valid.
Inputs must be either all FeatureClasses, Tables or Rasters; not mixed
Failed to execute (Append).

So I think it may like:
...
        # Process: Append the value table (from shp) into the SDE feature class
        gp.Append_management(vt, outfc, "NO_TEST", fieldmappings)
...
in pythonwin but hate this statement in the arctoolbox script??? I know I am importing point features only - so not mixing different different datasets!
Any ideas?

Re: Field mapping syntax (python)

SimonWillis — Wed, 07 Jul 2010 14:41:03 GMT

So it looks like this may be a bug that has existed since 2007 *gasp*
http://forums.esri.com/Thread.asp?c=93&f=1729&t=223204
ESRI / dear Jack, if you read this, are we moving on this or not? It seems the problem still exists in 931 ... do I dare ask about 10?

Well, at least Holland in the world cup final...
Hup Holland Hup!

Re: Field mapping syntax (python)

SimonWillis — Thu, 08 Jul 2010 20:11:21 GMT

Update:
I have been corresponding with ESRI support. They said:
"...I also suspect the 9.2 script tool is not liking the value table for some yet unknown reason. I couldn't find any bugs reported for this, so at least there is hope for us..."

gp.Append_management(vt, outfc, "NO_TEST", fieldmappings)

this worked in pythonwin using a valid argument but as a script in arctoolbox92 I got this error:
"Inputs must be either all FeatureClasses, Tables or Rasters; not mixed
Failed to execute (Append)."
Based on this error I found a solution (for 92 and python24). I removed any reference to value tables, while keeping fieldmappings and fieldmap and I just used my input featureclass for the Append so:

gp.Append_management(fc, outfc, "NO_TEST", fieldmappings) # this works
gp.Append_management(vt, outfc, "NO_TEST", fieldmappings) # see error above

I hope it helps others!

Re: Field mapping syntax (python)

KimOllivier — Tue, 13 Jul 2010 08:44:43 GMT

I ended up using the tool in catalog to set it all up. I just went back and did a find-replace to change the file paths. Much quicker than typing all of it. I have a spatial join in one script that is 20685 characters long, most all of it is field mapping. I wrote papers shorter than that in college.

That is how I create field maps too, but you can set the workspace to shorten the paths to fit the fieldmap string into one line.

Re: Field mapping syntax (python)

SimonWillis — Tue, 13 Jul 2010 17:24:29 GMT

Another update. This comes from ESRI again

Another one of our analysts here previously had a similar issue and logged the following software bug:

[NIM002716; Some geoprocessing tools that take in a value table argument are not honoring gp.workspace command when run as script tools in ArcToolbox]

There is a possible workaround listed that I would like to you to please try at your convenience. For the Append tool value table input, please try specifying the full paths to the data when adding rows to the value table. According to the bug, this may allow it to work when added as a script tool.

This workaround worked for me!
So first I had:
vt.AddRow(fc)
and I changed it to:
bugfixfc = SHPworkspace + "\\" + fc
vt.AddRow(bugfixfc)

# back to using vt and append works!
gp.Append_management(vt, outfc, "NO_TEST", fieldmappings)

Re: Field mapping syntax (python)

SusanJones — Sat, 23 Jul 2011 03:19:19 GMT

Hi

I too struggled with this. Please see the following link http://forums.arcgis.com/threads/34881-replacefieldmap()-appears-broken-in-arcpy.

Susan