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

Aligning raster pixels


Another consideration when combining raster datasets in an analysis is whether the pixels align from dataset to dataset. Cells in different datasets can now be aligned in QGIS with the new Raster | Align Rasters tool. In fact, this tool also allows you to:

  1. Set the output CRS.

  2. Set the output Cell Size.

  3. Clip to a region of interest.

  4. If you need to both align and resample rasters, this tool can do both. In this example, we have a vegetation type raster (jemez_vegetation.tif) and an elevation raster (jemez_elevation.tif) for the Jemez Mountains in New Mexico, USA. The Align Rasters tool has been set up to align these rasters to the vegetation layer and set the output Cell Size to 30-meter pixels:

  5. The tool outputs new versions of each dataset. By selecting a Raster layers to align and clicking the Edit button, you can set the parameters of the output, including the Resampling method.