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

Summary


In this chapter, we continued our implementation of the ShapeEditor by adding three important functions: the list view and the ability to import and export shapefiles. While these aren't very exciting features, they are a crucial part of the ShapeEditor.

In the process of implementing these features, we learned how to use Django's templating language to display a list of records within a web page. We saw how to use the zipfile standard library module to extract the contents of an uploaded shapefile before opening that shapefile using OGR, and we discussed the concept of wrapping and unwrapping geometries to deal with the quirky way these are handled by the shapefile format. Finally, we saw how to use OGR to create a new shapefile that can be compressed using the zipfile library before being returned to the caller using the Django web interface.

With this functionality out of the way, we can now turn our attention to the most interesting parts of the ShapeEditor: the code that displays...