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

Importing DXF/DWG files

CAD files, such as DXF and DWG files, can be opened with QGIS. This recipe shows you how to do this.

How to do it…

  1. To open a DXF layer, select Add vector layer... in the Layer menu. In the dialog that opens, click on the Browse button to open the file selector dialog. Select the Autocad DXF format and then the file that you want to load.

  2. In the example dataset, you can find several DXF files. Select the Wake_ApproxContour_100.dxf file. Click on OK in the vector layer selector dialog and the layer will be added to your project, as shown in the following screenshot:

How it works…

DXF files are read as normal vector layers although they do not have the same structure as a regular vector layer as they do not allow adding arbitrary attributes to each geometry.

There's more…

The example DXF file that you opened contained just one type of geometry. DXF files can, however, contain several of them: in this case, they cannot be added to QGIS in one layer. When this happens, QGIS will ask you to select the type of geometry that you want to open.

In the sample dataset, you will find a file named CSS-SITE-CIV.dxf. Open it and you will see the following dialog:

Select one of the available geometries, and a layer will be added to your QGIS project.

Opening DWG files

DWG is a closed format of Autodesk. This means that the specification of the format is not available. For this reason, QGIS, like other open source applications, does not support DWG files. To open a DWG file in QGIS, you need to convert it. Converting it to a DXF file is a good option as this will let you open your file in QGIS without any problem. There are many tools to do this. The Teigha converter can be found at and is a popular and reliable option.

Another option is using the free service offered by Autodesk, called Autocad 360, which can be found at