Running ArcPy Scripts from the Python Command Line

Why?

Sometimes there might not be a real reason to use a dialog box

We can still get input into the script

A Simple Example

Open ArcMap and either open an existing mxd or create a new one

If you created a new one, save it in a convenient folder

Open Notepad or Sublime, create a new file, and save it as HelloCommandLine.py in the same folder as your mxd file (not necessary, but possibly convenient)

Add this text to your file:

import arcpy

print 'loaded HelloCommandLine.py'

def greetings(name):

print 'Howdy ' + name + '!'

Open the Python window in ArcMap and enter

>>> execfile('PATH\ HelloCommandLine.py')

Where PATH is the pathname of the folder containing your Python script

For me, the command looks like this:

>>> execfile('r:\GOG530ArcPython\HelloCommandLine.py')

loaded HelloCommandLine.py

Now you can run methods defined in the script like this:

>>> greetings('fred')

Howdy fred!

Not much yet, but we�ll build on this

The important thing to note is that we load a script containing� functions, data structures, classes, etc.

Then we can call functions, fill data structures, and instantiate class objects from the command line

A More Useful Example

Let�s create a script that loads all shapefiles in a given folder

We need to get a folder from the user and scour it for shapefiles

A good way to do this will be to create a new method, LoadAllShapefiles(PATH), that takes a path to a specific folder

(I have modified this ArcGIS code sample found here as a base)

Copy and paste the code here into a Python module called LoadAllMyShapefiles.py

You can download and uncompress this set of 3 shapefiles to play with

Now load the module using the execfile() command (substitute your own path):

>>> execfile('r:\\gog530ArcPython\LoadAllMyShapefiles111517.py')

Here is the only function in this module:

LoadAllMyShapefiles(mypath)

Calling this function with a path loads and displays all shapefiles in the folder identified by mypath

You could call it like this:

>>> LoadAllMyShapefiles('r:\\gog530ArcPython\\shapefiles')

And all the shapefiles in r:\gog530ArcPython\shapefiles\ would be loaded onto the current map

Let�s look at the code line by line:

import arcpy # All of our ArcGIS scripts will refer to this module

from arcpy import env # for setting the working folder

Looking at the function LoadAllMyShapefiles(mypath)

env.workspace = mypath

Sets the workspace to the folder containing the user�s shapefiles

fcList = arcpy.ListFeatureClasses()

Gets all the shapefiles in the workspace, if any, and saves them in a list (fcList)

�� mxd = arcpy.mapping.MapDocument("CURRENT")

�� df = arcpy.mapping.ListDataFrames(mxd, '')[0]

Old stuff�get the current map document and dataframe 0

Now we can loop through fcList to load our shapefiles into our current map document:

for fc in fcList:

# for each shapefile found in the folder,

# create a complete path that includes the shapefile

pathToFC = env.workspace + '/' + fc

# create a layer from the path

newlayer = arcpy.mapping.Layer(pathToFC)

# add the layer to the dataframe

arcpy.mapping.AddLayer(df,newlayer,"BOTTOM")

Finishing up (more familiar stuff):

�� #Refresh Table of Contents

�� arcpy.RefreshTOC()

�� #Refresh Active View

�� arcpy.RefreshActiveView()

Things for you to try:

Implement a ZoomToLayer() function that is called with the layer name as a string

Implement a BringToTop() function that raises a layer to the top of the TOC by name

Write a DeleteAllLayers() function that deletes all layers in a map document (be careful�)

Here is one of my attempts using for loops

Here is the same thing using dictionaries (not entirely working yet)