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

Tracking a GPS

QGIS has the ability to connect to a GPS that uses the National Marine Electronics Association (NMEA) standard. QGIS can use a serial connection to the GPS or communicate with it through the open source software called gpsd using the QGIS GPS information panel. The location information from the GPS can be displayed on the QGIS map, and QGIS can even automatically pan the map to follow the GPS point. In this recipe, we'll use the QGIS API to process NMEA sentences and update a point on a global map. The information needed to connect to different GPS units can vary widely, so we'll use an online NMEA sentence generator to get some simulated GPS information.

Getting ready

This recipe doesn't require any preparation.

How to do it...

We'll grab a batch of NMEA GPS sentences from a free online generator, create a worldwide basemap using online GeoJSON data, create a vector point layer to represent the GPS, and finally loop through the sentences and make our track point move around the...