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

Using the 2.5D renderer

The 2.5D renderer is a powerful new visualization for QGIS, which allows you to present buildings as three-dimensional shapes from a single angle. The locked viewpoint is why the developers named it 2.5D or 2 ½ D instead of full 3D. In this recipe, we'll render a small set of building footprints in 2.5D, with height values set as a shapefile attribute in the sample footprints.

Getting ready

Download the zipped building footprints shapefile from the following URL:

Extract it into a directory called hancock in your qgis_data directory.

How to do it...

We will create the vector layer, assign it the special renderer, configure the renderer, and finally add it to the map to see the result. We will be using a special set of properties that is normally reserved for labelling settings in QGIS:

  1. First, create the layer from the building footprints shapefile:

            lyr = QgsVectorLayer("/qgis_data/hancock/buildings...