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 geospatial data


In this section, we will look at some examples of tasks you might want to perform that involve using geospatial data in both vector and raster format.

Task – calculate the bounding box for each country in the world

In this slightly contrived example, we will make use of a shapefile to calculate the minimum and maximum latitude/longitude values for each country in the world. This "bounding box" can be used, among other things, to generate a map centered on a particular country. For example, the bounding box for Turkey would look like this:

Start by downloading the World Borders Dataset from http://thematicmapping.org/downloads/world_borders.php. Make sure you download the file named TM_WORLD_BORDERS-0.3.zip rather than the simplified TM_WORLD_BORDERS_SIMPL-0.3.zip file. Decompress the .zip archive and place the various files that make up the shapefile (the .dbf, .prj, .shp, and .shx files) together in a suitable directory.

Next, we need to create a Python program...