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

Summary


In this chapter, we have explored the Mapnik map-generation toolkit in depth. We learned the following:

  • Mapnik is a powerful and flexible toolkit for generating a variety of maps

  • Mapnik uses the painter's algorithm to draw the various parts of a map in the correct order

  • A map is made up of multiple layers

  • Map rendering is controlled using styles

  • Styles are defined within the map and are referred to by the layers, allowing styles to be shared between map layers

  • Each style consists of one or more rules

  • Each rule has a list of symbolizers, telling Mapnik how to draw the layer's features onto the map, and an optional filter which selects the features the rule applies to

  • You can use a map definition file as a simpler way of creating maps without having to define all the symbolizers, filters, rules, styles, and layers in Python

  • You can use a map definition file as a stylesheet, separating the logic of building a map from the way it is formatted, in the same way that an HTML templating engine separates...