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

Using Esri ArcGIS map services

Esri create its own version of the JSON format. QGIS now supports this special dialect of the JSON format Esri created for map services. It is almost similar to GeoJSON, but different enough to require special handling. There are two types of Esri services: ArcGIS map services, which provide tiled map layers, and ArcGIS feature services, which provide vector layers. In this recipe, we'll create a map with one of each type of service, including a world imagery basemap service and a 2011 worldwide earthquake point layer.

Getting Ready

For this example, it is important to ensure that the on-the-fly CRS transformation is turned off for your map project, because Esri services use a slightly different CRS (EPSG:3857), and we don't want QGIS to automatically assume WGS 84. To verify this setting, perform the following steps:

  1. Go to the QGIS Project menu and choose Project Properties....

  2. In the Project Properties dialog, choose the CRS panel on the left.

  3. In the CRS panel...