Book Image

QGIS Python Programming Cookbook, Second Edition - Second Edition

By : Joel Lawhead
Book Image

QGIS Python Programming Cookbook, Second Edition - Second Edition

By: Joel Lawhead

Overview of this book

QGIS is a desktop geographic information system that facilitates data viewing, editing, and analysis. Paired with the most efficient scripting language—Python, we can write effective scripts that extend the core functionality of QGIS. Based on version QGIS 2.18, this book will teach you how to write Python code that works with spatial data to automate geoprocessing tasks in QGIS. It will cover topics such as querying and editing vector data and using raster data. You will also learn to create, edit, and optimize a vector layer for faster queries, reproject a vector layer, reduce the number of vertices in a vector layer without losing critical data, and convert a raster to a vector. Following this, you will work through recipes that will help you compose static maps, create heavily customized maps, and add specialized labels and annotations. As well as this, we’ll also share a few tips and tricks based on different aspects of QGIS.
Table of Contents (16 chapters)
QGIS Python Programming Cookbook - Second Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Adding a table to the map


The QGIS composer provides an object to add a table to a composition, representing either the attributes of a vector layer or an arbitrary text table you create. In this recipe, we'll add a table to the composition with the attributes of our map layer shapefile.

Getting ready

Download the shapefile for this map from https://github.com/GeospatialPython/Learn/raw/master/Mississippi.zip and extract it to your qgis_data directory in a subdirectory named ms.

As with the previous recipes in this chapter, we will use the MapComposer library from https://github.com/GeospatialPython/Learn/raw/master/MapComposer.py, to simplify the creation of the map composition.

Place the file in the .qgis2/python directory within your home directory.

How to do it...

The following steps will create a map composition, add the table, and output the composition to an image:

  1. First, we import our GUI libraries and the MapComposer library:

            from PyQt4.QtCore import * 
            from PyQt4.QtGui...