ArcMap – Scripts Running Slower When Importing ArcPy

arcgis-10.0arcmaparcpy

I am finding ArcMap runs slower, if you have written a script, which imports arcpy.

You may wish to write a script that can be operated in ArcMap, through the python window, or as a standalone python script. If so, you'll have to import arcpy. However, if you do this and run it in the python window, it will run slower.

Best Answer

I have put this code into my script and it runs much quicker:

try:
    arcpy 
except NameError:
    import arcpy

This is saving considerable time in our scripts in ArcMap now.

This may all change in SP2, but none the less...

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[GIS] Why would “import arcpy” hang Python script run from DOS/cmd prompt

arcpy (actually arcgisscripting which it wraps) extends a specific version of python. At arcgis 10.0 you need to run with python26. I'd make sure all the versions are matching.

Instead of doing this

C:\> test.py

Do this

C:\> C:\python26\Desktop10.0\python.exe test.py

Then you know it's starting the correct version of python. If that second line works, what's happening is that windows is starting python25, you'll need to do one of these

1) update windows file association for .py files (quick/technical)

2) uninstall python25 & 26 and install from the install disk (still pretty quick, less technical)

ArcPy – How to Debug Scripts in ArcMap

Usually Python debuggers/IDEs assume the Python script is running in the same process as itself so debugging a script running in ArcMap.exe is right out -- you need to get enough of the GP scripting environment bootstrapped in a Python script as you can to debug with.

A method that's worked very well for me over the past few years is to write a simple script that just calls the tool and use that as my main script in the Python IDE (Wing or Pythonwin) and have my breakpoints set in the tool's .py file also open in the same IDE session.

So basically I do this:

Get the set of inputs that aren't working in my script tool
Open a simple .py file in the same folder as the .tbx that calls the tool
Open up the caller script and the script tool .py file in the IDE
Set breakpoints in script tool file
Run the caller script

And my caller script is usually pretty simple:

import os
import arcpy
arcpy.ImportToolbox(os.path.join(os.path.dirname(__file__), 'my.tbx'))
arcpy.MyToolThatIsFailing_myalias("inputs", "that", "don't" "work")

I've tried winpdb to debug scripts running in ArcMap but I've never had any luck. If you want to try it out and you get it working well, please share your findings.

Best Answer

Related Solutions

[GIS] Why would “import arcpy” hang Python script run from DOS/cmd prompt

ArcPy – How to Debug Scripts in ArcMap

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