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

Adding a world file to a map image

Exporting a map as an image removes all of its spatial information. However, you can create an external text file, called a world file, which provides the georeferencing information for the raster image so that it can be used by GIS software, including QGIS, as a raster layer. In this recipe, we'll export a map composition as an image and create a world file along with it.

Getting ready

You will need to download the zipped shapefile from and extract it to your qgis_data directory in a subdirectory named ms.

In addition to the shapefile, you will also need the MapComposer class, to simplify the code needed to add this one element. If you have not already used it in a previous recipe, you can download it from

This file must be accessible from the QGIS Python console; for this, you need to ensure that it is in the Python path...