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

Chapter 2. Querying Vector Data

In this chapter, we will cover the following recipes:

  • Loading a vector layer from a file sample

  • Loading a vector layer from a geodatabase

  • Examining vector layer features

  • Examining vector layer attributes

  • Filtering a layer by geometry

  • Filtering a layer by attributes

  • Buffering a feature

  • Measuring the distance between two points

  • Measuring distance along a line

  • Calculating the area of a polygon

  • Creating a spatial index

  • Calculating the bearing of a line

  • Loading data from a spreadsheet

  • Accessing layer metadata