Book Image

Python Geospatial Development - Second Edition - Second Edition

By : Erik Westra
Book Image

Python Geospatial Development - Second Edition - Second Edition

By: Erik Westra

Overview of this book

Geospatial development links your data to places on the Earth's surface. 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. Python Geospatial Development - Second Edition teaches you everything you need to know about writing geospatial applications using Python. No prior knowledge of geospatial concepts, tools or techniques is required. The book guides you through the process of installing and using various toolkits, obtaining geospatial data for use in your programs, and building complete and sophisticated geospatial applications in Python. Python Geospatial Development teaches you everything you need to know about writing geospatial applications using Python. No prior knowledge of geospatial concepts, tools or techniques is required. The book guides you through the process of installing and using various toolkits, obtaining geospatial data for use in your programs, and building complete and sophisticated geospatial applications in Python. This book provides an overview of the major geospatial concepts, data sources and toolkits. It teaches 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. Because maps are such an important aspect of geospatial programming, 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 Geodjango. Whether you want to write quick utilities to solve spatial problems, or develop sophisticated web applications based around maps and geospatial data, this book includes everything you need to know.
Table of Contents (18 chapters)
Python Geospatial Development
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Visualizing geospatial data


It's very hard, if not impossible, to understand geospatial data unless it is turned into a visual form—that is, until it is rendered as an image of some sort. Converting geospatial data into images requires a suitable toolkit. While there are several such toolkits available, we will look at one in particular: Mapnik.

Mapnik

Mapnik is a freely-available toolkit for building mapping applications. It takes geospatial data from a PostGIS database, shapefile, or any other format supported by GDAL/OGR, and turns it into clearly-rendered, good-looking images.

There are a lot of complex issues involved in rendering maps well, and Mapnik does a good job of allowing the application developer to control the rendering process. Rules control which features should appear on the map, while "symbolizers" control the visual appearance of these features.

Mapnik allows developers to create XML stylesheets that control the map-creation process. Just as with CSS stylesheets, Mapnik's...