ArcPy and ArcGIS - Geospatial analysis with python : use the ArcPy module to automate the analysis and mapping of geospatial data in ArcGIS

224 Pages·2015·2.94 MB·English

by  Silas Toms

ArcPy and ArcGIS – Geospatial
Analysis with Python
Use the ArcPy module to automate the analysis and
mapping of geospatial data in ArcGIS
Silas Toms
BIRMINGHAM - MUMBAI
ArcPy and ArcGIS – Geospatial Analysis with Python
Copyright © 2015 Packt Publishing
All rights reserved. No part of this book may be reproduced, stored in a retrieval
system, or transmitted in any form or by any means, without the prior written
permission of the publisher, except in the case of brief quotations embedded in
critical articles or reviews.
Every effort has been made in the preparation of this book to ensure the accuracy
of the information presented. However, the information contained in this book is
sold without warranty, either express or implied. Neither the author, nor Packt
Publishing, and its dealers and distributors will be held liable for any damages
caused or alleged to be caused directly or indirectly by this book.
Packt Publishing has endeavored to provide trademark information about all of the
companies and products mentioned in this book by the appropriate use of capitals.
However, Packt Publishing cannot guarantee the accuracy of this information.
First published: February 2015
Production reference: 1210215
Published by Packt Publishing Ltd.
Livery Place
35 Livery Street
Birmingham B3 2PB, UK.
ISBN 978-1-78398-866-2
www.packtpub.com
[ FM-2 ]
Credits
Author Copy Editors
Silas Toms Aarti Saldanha
Adithi Shetty
Reviewers
Alessio Di Lorenzo
Project Coordinator
Dara O'Beirne Milton Dsouza
Mark Pazolli
Marjorie Roswell Proofreaders
Simran Bhogal
Joanna McMahon
Commissioning Editor
Ashwin Nair Bernadette Watkins
Acquisition Editor Indexer
Harsha Bharwani Priya Sane
Content Development Editor Production Coordinator
Akashdeep Kundu Alwin Roy
Technical Editor Cover Work
Deepti Tuscano Alwin Roy
[ FM-3 ]
About the Author
Silas Toms is a geospatial programmer and analyst with a love of geography,
history, food, and sports. He resides in the San Francisco Bay Area and can't
decide which side of the Bay is more beautiful. He received a bachelor's degree in
Geography from Humboldt State University and is currently pursuing a master's
degree in GIS at San Francisco State University. With a background in GIS analysis
for city governments and environmental consulting, Silas loves the combination of
GIS and Python for analysis automation and data manipulation.
Working for Arini Geographics, Silas is helping governments understand how GIS
can organize and simplify the management of infrastructure and the environment.
This dual role as a programmer and analyst allows him to use Python and GIS to
quickly produce geospatial data and tools. Combined with web mapping, these
tools are transforming how governments work to serve the public. He also teaches
workshops on ArcPy and web mapping at the City College of San Francisco, while
hoping to one day finish his master's thesis.
Silas has worked as a reviewer on the book Python Geospatial Analysis, Packt
Publishing and is working on the book Python Geospatial Development, Packt Publishing
to be published in 2015.
I would like to thank my girlfriend, Christine, for her encouragement
and patience. I would like to thank my boss, Gabriel Paun, for his
inspiration and for pushing me to become a true GIS professional. I
would like to thank the faculty at HSU and SFSU for their help along
the way, and I would like to thank my family for their belief in me
and for never asking me if I was going to become a teacher with my
geography degree (even though I have and I love it!).
[ FM-4 ]
About the Reviewers
Alessio Di Lorenzo is a marine biologist and has an MSc in Geographical
Information Systems (GIS) and Remote Sensing. Since 2006, he has been dealing with
the analysis and development of GIS applications dedicated to the study and spread
of environmental and epidemiological data. He is experienced in the use of the main
proprietary and open source GIS software and programming languages.
Dara O'Beirne is a certified GIS Professional (GISP) with over eight years of GIS
and Python experience. Dara earned both his Bachelors and Masters of Arts degrees
in geography from San Francisco State University. Dara is currently a GIS Analyst
working at Arini Geographics in Santa Clara, CA. Before joining Arini Geographics,
Dara was a GIS Analyst and technical lead at Towill Inc., a GIS and Land Surveying
company in Northern California. At Towill, Dara played a central role in developing
and implementing procedures related to the collection and analysis of LiDAR data
for environmental and engineering applications. Prior to Towill, Dara gained his
professional GIS experience working for the Golden Gate National Recreation Area
managed by the National Park Service, one of the largest urban park systems in
the world, which includes National treasures, such as Alcatraz, Muir Woods, and
the Marin Headlands. His Master's Thesis examined the errors associated with
measuring tree heights in an urban environment with both traditional field methods
and airborne LiDAR data.
I would like to thank my wife, Kate, and daughter, Anya O'Beirne,
for their patience and assistance during the review of this book.
[ FM-5 ]
Marjorie Roswell is a web developer and map maker from Baltimore, MD. She
purchased her first GIS in 1991, and built an application to assist citizen callers to the
Baltimore Office of Recycling. Recent projects include interactive maps of legislative
scores, political endorsements, committees, election data, and advocacy interests.
Her site http://committeemaps.org/ details Congressional committee
membership, while the site http://farmbillprimer.org/ is devoted to mapping
and charting federal food and farm policy.
Marjorie is the author of Drupal 5 Views Recipes, Packt Publishing. She was the technical
reviewer of jQuery UI 1.10, The User Interface Library for jQuery, Packt Publishing.
Mark Pazolli is an engineer and data scientist who uses ArcGIS and Python to help
his employers decipher the mountains of data they keep on the assets of the Western
Australian electrical network. He has qualifications in Electrical Engineering,
Computer Science, and Applied Mathematics. He appreciates excellent design and
enjoys building interesting things.
[ FM-6 ]
www.PacktPub.com
Support files, eBooks, discount offers, and more
For support files and downloads related to your book, please visit www.PacktPub.com.
Did you know that Packt offers eBook versions of every book published, with PDF
and ePub files available? You can upgrade to the eBook version at www.PacktPub.
com and as a print book customer, you are entitled to a discount on the eBook copy.
Get in touch with us at [email protected] for more details.
At www.PacktPub.com, you can also read a collection of free technical articles, sign
up for a range of free newsletters and receive exclusive discounts and offers on
Packt books and eBooks.
TM
https://www2.packtpub.com/books/subscription/packtlib
Do you need instant solutions to your IT questions? PacktLib is Packt's online digital
book library. Here, you can search, access, and read Packt's entire library of books.
Why subscribe?
• Fully searchable across every book published by Packt
• Copy and paste, print, and bookmark content
• On demand and accessible via a web browser
Free access for Packt account holders
If you have an account with Packt at www.PacktPub.com, you can use this to access
PacktLib today and view 9 entirely free books. Simply use your login credentials for
immediate access.
[ FM-7 ]

Table of Contents
Preface 1
Chapter 1: Introduction to Python for ArcGIS 7
Overview of Python 7
Python as a programming language 8
Interpreted language 8
Standard (built-in) library 9
The glue language 9
Wrapper modules 9
The basics of Python 10
Import statements 11
Variables 12
For loops 13
If/Elif/Else statements 14
While statements 14
Comments 15
Data types 15
Strings 16
Integers 16
Floats 17
Lists 17
Tuples 18
Dictionaries 18
Iterable data types 19
Other important concepts 20
Indentation 20
Functions 21
Keywords 21
Namespaces 21
Zero-based indexing 22