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

Importing shapefiles


The process of importing a shapefile involves the following steps:

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

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

  3. Open the shapefile and read its data into the database.

  4. Delete the temporary files we have created.

Let's work through each of these steps in turn.

The Import Shapefile form

Let's start by creating a placeholder for the "Import Shapefile" view. Edit the urls.py module and add a new entry to the urlpatterns list:

url(r'^import$', shapeEditor.shapefiles.views.import_shapefile),

Then, edit the shapeEditor/shapefiles/views.py module and add a dummy import_shapefile() view function to respond to this URL:

def import_shapefile(request):
    return HttpResponse("More to come")

You can test this if you want: run the Django server, go to the main page, and click on the Import New Shapefile button. You should see the More to come message.

To let the user enter data, we're going to use a Django...