Book Image

QGIS Python Programming Cookbook, Second Edition - Second Edition

By : Joel Lawhead
Book Image

QGIS Python Programming Cookbook, Second Edition - Second Edition

By: Joel Lawhead

Overview of this book

QGIS is a desktop geographic information system that facilitates data viewing, editing, and analysis. Paired with the most efficient scripting language—Python, we can write effective scripts that extend the core functionality of QGIS. Based on version QGIS 2.18, this book will teach you how to write Python code that works with spatial data to automate geoprocessing tasks in QGIS. It will cover topics such as querying and editing vector data and using raster data. You will also learn to create, edit, and optimize a vector layer for faster queries, reproject a vector layer, reduce the number of vertices in a vector layer without losing critical data, and convert a raster to a vector. Following this, you will work through recipes that will help you compose static maps, create heavily customized maps, and add specialized labels and annotations. As well as this, we’ll also share a few tips and tricks based on different aspects of QGIS.
Table of Contents (16 chapters)
QGIS Python Programming Cookbook - Second Edition
About the Author
About the Reviewer
Customer Feedback

Make a globe-like azimuthal orthographic projection

Sometimes, you want to provide a globe-like view on a static GIS map. Azimuthal orthographic projections can warp a layer containing countries to represent a round globe. In this recipe, we'll present data in one of these projections, named Sphere Azimuthal Equidistant.

Getting ready

You will need the Clip to Hemisphere plugin. Use the QGIS plugin manager to install it. The plugin will appear in the Processing Toolbox. You will also need to download the following zipped shapefile and extract it to your qgis_data directory:

How to do it...

We are going to load the countries shapefile and clip it by centering the map on Africa and then removing the portions of the map that would be out of view on a globe. Then, we'll reproject the map to achieve the globe affect:

  1. First, we import the Processing Toolbox:

            import processing 
  2. Next, we'll establish the path to our shapefile...