Book Image

Python Geospatial Development - Third Edition

By : Erik Westra
Book Image

Python Geospatial Development - Third Edition

By: Erik Westra

Overview of this book

Geospatial development links your data to locations on the surface of the Earth. Writing geospatial programs involves tasks such as grouping data by location, storing and analyzing large amounts of spatial information, performing complex geospatial calculations, and drawing colorful interactive maps. In order to do this well, you’ll need appropriate tools and techniques, as well as a thorough understanding of geospatial concepts such as map projections, datums, and coordinate systems. This book provides an overview of the major geospatial concepts, data sources, and toolkits. It starts by showing you how to store and access spatial data using Python, how to perform a range of spatial calculations, and how to store spatial data in a database. Further on, the book teaches you how to build your own slippy map interface within a web application, and finishes with the detailed construction of a geospatial data editor using the GeoDjango framework. By the end of this book, you will be able to confidently use Python to write your own geospatial applications ranging from quick, one-off utilities to sophisticated web-based applications using maps and other geospatial data.
Table of Contents (20 chapters)
Python Geospatial Development Third Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Working with GIS data manually


Let's take a brief look at the process of working with GIS data manually. Before we can begin, there are two things you need to do:

  • Obtain some GIS data

  • Install the GDAL library and its Python bindings so that you can read the necessary data files

Obtaining the data

Let's use the US Census Bureau's web site to download a set of vector maps for the various US states. The main site for obtaining GIS data from the US Census Bureau can be found at http://www.census.gov/geo/www/tiger.

To make things simpler, though, let's bypass the web site and directly download the file we need from http://www2.census.gov/geo/tiger/TIGER2014/STATE/tl_2014_us_state.zip.

The file, tl_2014_us_state.zip, should be a ZIP-format archive. After uncompressing the archive, you should have a directory containing the following files:

  • tl_2014_us_state.dbf

  • tl_2014_us_state.prj

  • tl_2014_us_state.shp

  • tl_2014_us_state.shx

These files make up a shapefile containing the outlines of all the US states...