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
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Cleaning up the attribute table


There are many reasons why we need to clean up attribute tables every now and then. These may be because we receive badly structured or named data from external sources, or because data processing, such as the layer joins that we performed in the previous exercise, require some post processing. This recipe shows us how to use attribute table and the Table Manager plugin to rename, delete, and reorder columns, as well as how to convert between different data types using Field Calculator.

Getting ready

If you performed the previous recipe, just save the joined layer to a new shapefile; otherwise, load census_wake2000_pop.shp. In any case, you will notice that the dataset contains a lot of duplicate information, and the column names could use some love as well. To follow this recipe, you should also install and enable the Table Manager plugin by navigating to Plugins | Manage and Install Plugins.

How to do it…

  1. Our first step to clean up this dataset is to delete...