Introduction to Python for GIS

Programming with computers is one of the most rewarding and frustrating of human endeavors.

Those rewards can be in the form of money, as we can see with today’s high-tech salaries. I would argue, however, that the most rewarding part of mastering programming is to make yourself into a computer power user who can execute both simple and complex applications and analyses, written in reusable code, with ease.

The frustrations will come and go, and it is a good thing: you, like me and millions before you, will learn from each mistake. You will grow and learn with each exercise in this book, and by asking the right questions and paying close attention you can avoid some of these issues.

If you are an ArcGIS expert or novice, seeking to expand on your skillsets, congratulations – you are in the right place. In this book, you will learn how to take your existing GIS expertise (or interest) and multiply its potential using a deceptively simple programming language called Python.

Computer programming is a vast field of knowledge, about which whole books have been written. In this chapter, we will explain the basic knowledge necessary to read, write, and run Python scripts. We’ll leave the ArcGIS tools for later chapters and focus on Python: its beginnings, its current state, how to use it, and importantly, what Python is and what it is not.

We will cover the following topics:

• The basics of Python
• The basics of computer programming
• Installing and importing modules
• Writing and executing scripts