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

Designing the ShapeEditor


Let's take a closer look at the various parts of the ShapeEditor in order to see what's involved in implementing it. The ShapeEditor is going to support the following activities:

  • Importing geospatial features and attributes from a shapefile

  • Allowing the user to select a feature to be edited

  • Displaying the appropriate type of editor to allow the user to edit the feature's geometry

  • Exporting geospatial features and attributes back to a shapefile

Let's take a closer look at each of these user activities in order to see how they will be implemented within the ShapeEditor system.

Importing a shapefile

When the user imports a shapefile, we will store the contents of that shapefile in the database so that GeoDjango can work with it. Because we don't know in advance which types of geometries the shapefile will contain or what attributes might be associated with each feature, we need to have a generic representation of a shapefile's contents in the database rather than defining...