Book Image

QGIS 2 Cookbook

By : Mandel, Olaya Ferrero, Anita Graser
Book Image

QGIS 2 Cookbook

By: Mandel, Olaya Ferrero, Anita Graser

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 (14 chapters)
13
Index

Exploring spatiotemporal vector data using Time Manager

In this recipe, we will look at exploring spatiotemporal vector data using the Time Manager plugin. We'll use event data from the ACLED (Armed Conflict Location and Event Data Project) at http://www.acleddata.com/about-acled/.

Getting ready

To follow this recipe, please load ACLED_africa_fatalities_dec2013.shp. The layer style that you will see in the following screenshots consists of a simple circle marker at 50% transparency with the data-defined size set to the number of fatalities of the incident. (You can read more about styling in Chapter 10, Cartography Tips, and Learning QGIS book by Packt Publishing.) If you want some additional geographic context, you can also load NE_africa.shp, which contains the outline of Africa.

How to do it…

Once the data is loaded, all event positions will be displayed. The default way to filter the events, for example, to only see the events from December 1, is to use Layer | Query and enter...