Book Image

QGIS 2 Cookbook

By : Alex Mandel, Víctor Olaya Ferrero, Anita Graser, Alexander Bruy
Book Image

QGIS 2 Cookbook

By: Alex Mandel, Víctor Olaya Ferrero, Anita Graser, Alexander Bruy

Overview of this book

QGIS is a user-friendly, cross-platform desktop geographic information system used to make maps and analyze spatial data. QGIS allows users to understand, question, interpret, and visualize spatial data in many ways that reveal relationships, patterns, and trends in the form of maps. This book is a collection of simple to advanced techniques that are needed in everyday geospatial work, and shows how to accomplish them with QGIS. You will begin by understanding the different types of data management techniques, as well as how data exploration works. You will then learn how to perform classic vector and raster analysis with QGIS, apart from creating time-based visualizations. Finally, you will learn how to create interactive and visually appealing maps with custom cartography. By the end of this book, you will have all the necessary knowledge to handle spatial data management, exploration, and visualization tasks in QGIS.
Table of Contents (19 chapters)
QGIS 2 Cookbook
About the Authors
About the Reviewers

Visualizing multispectral layers

Multispectral layers can be rendered in different ways depending on how bands are used. This recipe shows you how to do this and discusses the theory behind it.

Getting ready

Open the landsat.qgs project.

How to do it…

  1. The Landsat image, when opened with the default configuration, looks something like the following screenshot:

  2. Double-click on the layer to open its properties and move to the Style section:

    1. Select the band number 4 in the Red band field.

    2. Select the band number 3 in the Green band field.

    3. Select the band number 2 in the Blue band field.

    Your style configuration should be like the following:

  3. Click on OK.

The image should now look like the following:

How it works…

Colors representing a given pixel are defined using the RGB color space, which requires three different components. A normal image (such as the one you will get from a digital camera) has three bands containing the intensity for each one of these three components: red, green, and blue.