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
About the Author
About the Reviewer
Customer Feedback

Creating a dock widget

All the panels in QGIS are dock widgets. These widgets can attach to a side of the main window or float freely in a separate window. These panels can contain any other type of widget, which is why they are usually the interface for QGIS plugins. In this recipe, we'll create a dock widget with a text editor widget inside.

Getting ready

Open the QGIS Python console by selecting the Plugins menu and then clicking on Python Console.

How to do it...

We'll create a QTextEdit widget. Then we'll create a QDockWidget and place the QTextEdit widget inside it. Finally we'll display the dock widget in the main window:

  1. First, we import the Qt libraries, which contain all the widgets:

            from PyQt4.QtCore import * 
            from PyQt4.QtGui import * 
  2. Next, we create the text edit widget with a default message:

            te = QTextEdit("<b>Project notes:</b>") 
  3. Now, we create the dock widget with a title:

            dw = QDockWidget("QGIS Sticky Notes") 
  4. Now...