Book Image

Mastering QGIS - Second Edition

By : Kurt Menke, GISP, Paolo Corti, Richard Smith Jr., GISP, Luigi Pirelli, John Van Hoesen, GISP
Book Image

Mastering QGIS - Second Edition

By: Kurt Menke, GISP, Paolo Corti, Richard Smith Jr., GISP, Luigi Pirelli, John Van Hoesen, GISP

Overview of this book

QGIS is an open source solution to GIS. It is widely used by GIS professionals all over the world. It is the leading alternative to the proprietary GIS software. Although QGIS is described as intuitive, it is also by default complex. Knowing which tools to use and how to apply them is essential to producing valuable deliverables on time. Starting with a refresher on the QGIS basics, this book will take you all the way through to creating your first custom QGIS plugin. From the refresher, we will recap how to create, populate, and manage a spatial database. You’ll also walk through styling GIS data, from creating custom symbols and color ramps to using blending modes. In the next section, you will discover how to prepare vector, heat maps, and create live layer effects, labeling, and raster data for processing. You’ll also discover advanced data creation and editing techniques. The last third of the book covers the more technical aspects of QGIS such as using LAStools and GRASS GIS’s integration with the Processing Toolbox, how to automate workflows with batch processing, and how to create graphical models. Finally, you will see how to create and run Python data processing scripts and write your own QGIS plugin with pyqgis. By the end of the book, you will understand how to work with all the aspects of QGIS, and will be ready to use it for any type of GIS work.
Table of Contents (19 chapters)
Mastering QGIS - Second Edition
Credits
Foreword
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Creating a raster composite


To combine many separate raster files (each representing one raster band) into a raster composite, we can use the r.composite tool in the Processing Toolbox. The Processing Toolbox (which is covered in detail in Chapter 8, The Processing Toolbox) allows us to access tools from GRASS GIS, which contains the r.composite tool. The r.composite tool assigns three singleband rasters to a red, green, and blue raster band and produces one multiband raster.

To open the r.composite tool, open the Processing Toolbox first by navigating to Processing | Toolbox. In the search box at the top of the Processing Toolbox, type r.composite to find the tool and then double-click on the tool to open it. This will open the r.composite tool window, as shown in the following screenshot:

The r.composite tool has a number of parameters that can be set and these are as follows:

  • Red: This includes the raster that will be assigned to the red band.

  • Green: This include the raster that will be...