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

Introducing PostGIS


In this book, we will be working with PostGIS. PostGIS is one of the most popular and powerful geospatial databases and has the bonus of being open source and freely available. PostGIS itself is actually an extension to the PostgreSQL relational database system—to use PostGIS from your Python programs, you first have to install and set up PostgreSQL, then install the PostGIS extension, and then finally install the psycopg2 database adapter for Python. The following illustration shows how all these pieces fit together:

Tip

Note that PostgreSQL is often referred to as Postgres. We will regularly use this more colloquial name throughout this book.

PostGIS allows you to store and query against various types of spatial data, including points, lines, polygons, and geometry collections. PostGIS provides two different types of spatial fields that can be used to store spatial data:

  • The geometry field holds spatial data that is assumed to be in a projected coordinate system. All calculations...