Why doesn't Python script add output automatically to map?

KirstynAlex

This is the first Python script I've written in a few years, so this is probably a rookie question.

I wrote this script that creates 3 different buffers around a point shapefile, and it works, but doesn't automatically add the buffers to the map, it just saves them in the specified workspace. In my Geoprocessinng options I have it set to add outputs to map and it works with all ESRI tools but not my script. Any ideas? Thanks in advance!

Here is my script:

# Script Name: EpicenterBuffers
# Description: Creates 10, 50, and 100 KM
#              buffers around an epicenter
# Created By:  Kirstyn Pittman
# Date:        11/24/14


import arcpy
arcpy.env.workspace = r"H:\Drafting Department\Python\EpicenterBuffers"
shp = "Location"
distanceList = ["10 kilometers","50 kilometers","100 kilometers"]
# Loop through each distance in the distanceList
for dist in distanceList:
    outName = shp+"_"+dist
    arcpy.Buffer_analysis(shp, outName, dist)
print "Finished Buffering"

RichardFairhurst

A standalone python script is not a geoprocessing tool, and the import of arcpy does not replicate all of the behaviors that operate within an open session of ArcMap.  Environment settings that apply directly to an open session of ArcMap are ignored by Python scripts, such as arcpy.overwriteOutputs = True and arcpy.addOutputsToMap = True; but they are exposed through arcpy to control the user experience in an open session of ArcMap (i.e., whatever arcpy did to these settings will persist and affect how ArcMap responds when the user tries to save over a file or run a geoprocessing tool, so a programmer can control user capabilities).

You need to explicitly do these tasks with arcpy.  You have to use the arcpy.mapping.AddLayer method to have your script add layers after creating new data.  You also cannot overwrite data, and have to test if it exists and then delete it with arcpy.Exists() and arcpy.Delete_management() (the Exist sample code demonstrates this).