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 horizontal legend

One of the map legend customization options is the direction. You can make an unusual horizontal legend just by changing the column count from the default of 1. In this recipe, we'll add two layers and set up the legend to run horizontally across the top of the map.

Getting ready

Download the first shapefile for this map from:

Download the second shapefile from here:

Extract both zip files to your qgis_data directory, to a subdirectory named ms.

As with the previous recipes in this chapter, we will use the MapComposer library from

This script will simplify a lot of the repetitive code needed for the creation of the map composition.

Extract the zip file and place the script in the .qgis2/python directory within your home directory.

How to do it...

We will set...