Book Image

Learn QGIS - Fourth Edition

By : Andrew Cutts, Anita Graser
Book Image

Learn QGIS - Fourth Edition

By: Andrew Cutts, Anita Graser

Overview of this book

QGIS 3.4 is the first LTR (long term release) of QGIS version 3. This is a giant leap forward for the project with tons of new features and impactful changes. Learn QGIS is fully updated for QGIS 3.4, covering its processing engine update, Python 3 de-facto coding environment, and the GeoPackage format. This book will help you get started on your QGIS journey, guiding you to develop your own processing pathway. You will explore the user interface, loading your data, editing, and then creating data. QGIS often surprises new users with its mapping capabilities; you will discover how easily you can style and create your first map. But that’s not all! In the final part of the book, you’ll learn about spatial analysis and the powerful tools in QGIS, and conclude by looking at Python processing options. By the end of the book, you will have become proficient in geospatial analysis using QGIS and Python.
Table of Contents (8 chapters)

Combining raster and vector data

As discussed in Chapter 2, Data Creation and Editing, raster and vector data are the main sources of GIS data. These are often analyzed separately. However, more complex analyses sometimes require a combination of raster and vector data. We often need to convert raster data to vector data and vice versa. QGIS has this ability and uses GDAL calls (Polygonize and Rasterize) respectively. In the following exercises, we will use both raster and vector datasets to explain how to convert between these different data types. We will also look at how to access layer and zonal statistics, and finally, how to create a raster heatmap from point data.

Converting between rasters and vectors

Tools for converting...