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Setting Script Tool Parameters - Python in ModelBuilder

NickBauer

Hi All,

I am wondering if you could help with following. Essentially it relates to the following help article "Setting Script Tool Parameters" ArcGIS Help (10.2, 10.2.1, and 10.2.2)

I have a used ModelBuilder to create a geoprocessing workflow. However for part of this I need to run a script within the model to dissolve some features within a layer (the inbuilt modelbuilder geoprocessing function for this does not give me multi-part polygons, despite this being a supposed option).

Thanks in advance (Using ArcGIS 10.2)

Nick

Essentially the problem I encounter is that when I run the model ArcGIS goes in to 'not responding mode' and does not recover. I suspect there is something wrong with wither my python script or the way I am passing variables between modelbuilder and my python script?

Python Script - Dissolve2

import arcpy

arcpy.env.workspace = "C:/Data/ArcGIS/Default.gdb/Dissolve1"

inLayer = arcpy.GetParameter(0)

outLayer = "C:/Data/ArcGIS/temp/OutDisolve.shp"

arcpy.Dissolve_management(inLayer, outLayer, "Id", "","MULTI_PART", "")

arcpy.SetParameter(1, OutLayer)

I have provided screenshots below

1. A simplified view of the model

2. Parameter Input and Output

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curtvprice

It should work as the current workspace does not come into play when complete paths are provided. In fact I don't see a reason to set the workspace at all in his model. (It is a simplified model he kindly provided, so there is probably more going on we don't know about.

I would avoid setting workspaces to be feature datasets unless there was a reason (ie making the code easier to read when processing data within a feature dataset. I could imagine there may be some bugs he may run into.

SepheFox

Actually, I didn't know it could be a dataset, so thanks for that info, but what Nick's trying to use is not clear, since his script tool dialog says the input is a shapefile, so I would think he would want his workspace to be a folder.

curtvprice

Just to make sure it's clear for the good of the thread:

A workspace can be a folder, a geodatabase, or a feature dataset (within a geodatabase).

SepheFox

The first thing I noticed is that your workspace is set to a feature class inside a gdb, as Susan is saying. The workspace should be either a GDB or a folder.

WesMiller

Have you checked the "id" field to ensure there are multiple matching values in that field?

SusanJones

Your workspace is set as a folder inside of a file geodatabase,

Your output layer is specifying an output shapefile.

The data type is incompatible

Try

arcpy.env.workspace = "C:/Data/ArcGIS/Default.gdb/"

Replace

outLayer = "OutDisolve"

Susan

SusanJones

Your workspace is set as a folder inside of a file geodatabase,

Your output layer is specifying an output shapefile.

The data type is incompatible

Try

arcpy.env.workspace = "C:/Data/ArcGIS/Default.gdb/"

Replace

outLayer = "C:/Data/ArcGIS/temp/OutDisolve"

Susan

curtvprice

No I have not seen this behavior. I'm wondering if there is a logic thing going on here.

The raw strings are only needed when you are passing a model variable that is a path (like a dataset path) into the function used by Calculate Value. The r is needed to ensure the backslashes are always interpreted as path delimeters instead of part of an escape sequence (for example so "path\temp" isn't intepretes as "path" + <tab> + "emp").

NickBauer1

Curtis Price wrote:
> (the inbuilt modelbuilder geoprocessing function for this does not give me multi-part polygons, despite this being a supposed option).
I'm kind of confused by this because the Dissolve tool is the same tool, whether called from ModelBuilder, a Python script, or run from a toolbox in ArcMap interactively.

Hi Curtis, yes I agree that the underlying tools are (should) be the same... but when I put the dissolve action into modelbuilder I can't seem to get it make multi-polygons (only single-part), despite this being an obvious option to specify? Is this your experience?

With regards to the "Calculate Value Tool" should the expression have an r before %OutName%? This does seem like a more simple way to go. Do you know of any other examples I can follow?

Thanks

Nick

NickBauer1

Thanks Curtis,

This is definitely helping me eliminate some issues, but I am still trying to get to the bottom of the issue I am having.

NickBauer1

Thanks picking this up Darren,

I have tried this but it does not seem to be the source of my issue. I am still trying to solve this.

Cheers

Nick

NickBauer

Thanks Freddie,

No I have tried with several different and simplified datasets and this does not help.

curtvprice

GetParameterAsText and SetParameterAsText should always be used unless you have a good reason to use the GetParameter and SetParameter functions. The GP environment is really setup to move data around as strings (think XML) and generally you'll be happier just going with that flow.

As for trapping exceptions and traceback - always a great idea. There are some nice code samples in the help here:

Error handling with Python—Help | ArcGIS for Desktop

JohnBrodnicki

I'm not sure if it will help but you may want to try changing arcpy.GetParameter(0) to arcpy.GetParameterAsText(0). If that doesn't help you may want to use a

try:

code

except arcpy.ExecuteError:

msg = arcpy.GetMessage(0)

arcpy.AddError(msgs)

This might show what's going wrong. If not, you could import os and traceback and write a more detailed "except" to catch other python errors.

curtvprice

> (the inbuilt modelbuilder geoprocessing function for this does not give me multi-part polygons, despite this being a supposed option).

I'm kind of confused by this because the Dissolve tool is the same tool, whether called from ModelBuilder, a Python script, or run from a toolbox in ArcMap interactively.

Another option to the overhead of setting up a script tool is to use the Calculate Value tool in ModelBuilder. Especially handy for situations where the logic of ModelBuilder validations and preconditions get complicated or problematic, but you don't want to bother with a python script tool.

Expression

proc(r"%InLayer%", r"%OutName%")

Code Block

import os
import arcpy
def  proc(lyr, outname):
  output = os.path.join(
    os.path.dirname(arcpy.Describe(lyr).catalogPath),
    outname)
  arcpy.Dissolve_management(lyr, output)
  return output

Data Type:

Feature Class

DarrenWiens2

Check the capitalization of outLayer vs. OutLayer. These are two different things according to Python.

Try:

arcpy.SetParameter(1, outLayer)

FreddieGibson

Does the Model freeze up with this particular dataset?

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