Introduction to ArcPy Scripting

What is ArcPy?

ESRI�s current environment that supports editing and execution of Python scripts

They support other languages too but we won�t be concerned with them in this course

There is also a universe of scripts in abandoned languages�let them die�

Scripts must be written in Python version 2.7 (the version we�re learning in class)

For us, a script is one or more Python modules that link with and call ArcPy modules to do stuff in ArcGIS

Scripts are very useful because they allow you to

Customize ArcGIS features for a specific set of users,

Access ArcGIS features that are not currently assigned to user interface controls,

Automate a set of frequently performed tasks, and

Do combinations of all these things

Refer to the instructions here to create toolboxes and scripts

All ArcPy scripts link to ArcGIS functionality by including the following statement as one of the first lines of executable code in a script:

import arcpy �# get the spelling and case correct here!!

Once you have this line of code in your file, you can call functions in the arcpy module like this:

arcpy.AddMessage('hello out there!') # prints text in the console

AddMessage() is a function in the arcpy module

Please note: Since the arcpy module is only available when you are running your script from within ArcGIS, this code will not run correctly from Eclipse, Sublime, or other python environments outside of ArcGIS

Poking around in arcpy

arcpy is organized into functions and classes

It also contains submodules (like arcpy.mapping) that contain yet more functions and classes

You don�t have to memorize all this stuff!!

Learning arcpy scripting

We will start out by writing �hello world� type scripts and then moving on to add real ArcGIS functionality

We will look at some existing scripts at ESRI and from contributed source

As you start working on projects, you will discover more functionality and get more ideas

Looking at other people�s scripts is a good thing

Try to understand what the code does�copying and pasting doesn�t help you at all

Copying without attribution is a bad thing!

Always note where you got something if you didn�t write the code yourself

At the least, this is just courteous to the original authors

You don�t want to be accused of ripping off someone else�s code