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

Reading and writing geospatial data


While you could, in theory, write your own parser to read a particular geospatial data format, it is much easier to use an existing Python library to do this. We will look at two popular libraries for reading and writing geospatial data: GDAL and OGR.

GDAL/OGR

Unfortunately, the naming of these two libraries is rather confusing. GDAL (short for Geospatial Data Abstraction Library), was originally just a library for working with raster-format geospatial data, while the separate OGR library was intended to work with vector-format data. However, the two libraries are now partially merged and generally downloaded and installed together under the combined name of GDAL. To avoid confusion, we will call this combined library GDAL/OGR and use GDAL to refer to just the raster translation library.

A default installation of GDAL allows you to read data in 100 different raster file formats, and write data in 71 different formats. OGR, by default, supports reading data...