Book Image

PostGIS Cookbook - Second Edition

By : Pedro Wightman, Bborie Park, Stephen Vincent Mather, Thomas Kraft, Mayra Zurbarán
Book Image

PostGIS Cookbook - Second Edition

By: Pedro Wightman, Bborie Park, Stephen Vincent Mather, Thomas Kraft, Mayra Zurbarán

Overview of this book

PostGIS is a spatial database that integrates the advanced storage and analysis of vector and raster data, and is remarkably flexible and powerful. PostGIS provides support for geographic objects to the PostgreSQL object-relational database and is currently the most popular open source spatial databases. If you want to explore the complete range of PostGIS techniques and expose related extensions, then this book is for you. This book is a comprehensive guide to PostGIS tools and concepts which are required to manage, manipulate, and analyze spatial data in PostGIS. It covers key spatial data manipulation tasks, explaining not only how each task is performed, but also why. It provides practical guidance allowing you to safely take advantage of the advanced technology in PostGIS in order to simplify your spatial database administration tasks. Furthermore, you will learn to take advantage of basic and advanced vector, raster, and routing approaches along with the concepts of data maintenance, optimization, and performance, and will help you to integrate these into a large ecosystem of desktop and web tools. By the end, you will be armed with all the tools and instructions you need to both manage the spatial database system and make better decisions as your project's requirements evolve.
Table of Contents (18 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Writing PostGIS functions with PL/Python


In this recipe, you will write a Python function for PostGIS using the PL/Python language. The PL/Python procedural language allows you to write PostgreSQL functions with the Python language.

You will use Python to query the http://openweathermap.org/ web services, already used in a previous recipe, to get the weather for a PostGIS geometry from within a PostgreSQL function.

Getting ready

  1. Verify your PostgreSQL server installation has PL/Python support. In Windows, this should be already included, but this is not the default if you are using, for example, Ubuntu 16.04 LTS, so you will most likely need to install it:
$ sudo apt-get install postgresql-plpython-9.1
  1. Install PL/Python on the database (you could consider installing it in your template1 database; in this way, every newly created database will have PL/Python support by default):

Note

You could alternatively add PL/Python support to your database, using the createlang shell command (this is the only...