Modelbuilder - calculate values - if feature exists

WilliamChow — Thu, 13 Nov 2014 00:48:54 GMT

I am new to modelbuilder and a noob in python.

I am trying to take a snippet of a py code from the ESRI blog particularly example 3 to use in my model.

My goal is to check if a "Polygons" fc exists in a gdb and if it does not return true to run a set of additional gp tools.

If you are stuck at "if" – Part 1 | ArcGIS Blog

Create variable

- Workspace - workspace variable

- location of gdb

- set as parameter for input as a tool

- FeatureClasstoCheck - feature class variable

- fc located in a feature dataset of the workspace

- set as input of based on parameter

- %workspace%\Placemarks\Polygons ??

Expression;

x("%FeatureClassToCheck%", "%Workspace%")

Code Block

def x(FeatureClassToCheck, Workspace):

import arcpy

arcpy.env.workspace = Workspace

if arcpy.Exists(FeatureClassToCheck):

return "true"

else:

return "false"

Data Type

Boolean

Now everytime I run this script, it returns a false value even though a actual Polygons fc exists. I've tried hardcoding the location of the gdb and feature class in the script but it still returns a false value.

Ive also tried to just copy the Polygons fc into the parent gdb and just running %workspace%\Polygons but still returns a false value.

I am working in a citrix environment so I am not sure if that could be an issue?

ie workspace location: \\abc.com\PROFILES\RemoteDesktop\chow\desktop\workspace\test.gdb

Any suggestions?

Thanks!

Re: Modelbuilder - calculate values - if feature exists

ChrisDonohue__GISP — Thu, 20 Nov 2014 19:55:54 GMT

Here's a guess based on something different between the ArcGIS help code example and your code:

Instead of:

arcpy.env.workspace = Workspace

Use:

env.workspace = Workspace

Based on ESRI's sample code in:

Checking for the existence of data

http://resources.arcgis.com/en/help/main/10.1/index.html#//002z0000001p000000

I'm not an expert on Python; but maybe that one syntax change may resolve the issue.

Chris Donohue, GISP

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Modelbuilder - calculate values - if feature exists

Re: Modelbuilder - calculate values - if feature exists