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

Importing shapefiles


The process of importing a shapefile involves the following steps:

  1. Displaying a form prompting the user to upload the shapefile's ZIP archive.

  2. Decompressing the ZIP file to extract the uploaded shapefile.

  3. Opening the shapefile and reading the data out of it into the database.

  4. Deleting the temporary files that we have created.

Because of the complexity of this process, we'll use a separate application called shapefileIO to handle the behind-the-scenes logic of importing (and later, exporting) the shapefile's contents. This allows us to implement the user interface for importing shapefiles, without having to worry about these behind-the-scenes details.

Let's start by creating the basic framework for the shapefileIO application. Using a terminal window, cd into the top-level directory and type the following:

python manage.py startapp shapefileIO

Then move the shapefileIO directory into the shapeEditor sub-directory, like this:

mv shapefileIO shapeEditor

While shapefileIO is a standard...