Book Image

QGIS:Becoming a GIS Power User

By : Ben Mearns, Alex Mandel, Alexander Bruy, Anita Graser, Víctor Olaya Ferrero
Book Image

QGIS:Becoming a GIS Power User

By: Ben Mearns, Alex Mandel, Alexander Bruy, Anita Graser, Víctor Olaya Ferrero

Overview of this book

The first module Learning QGIS, Third edition covers the installation and configuration of QGIS. You’ll become a master in data creation and editing, and creating great maps. By the end of this module, you’ll be able to extend QGIS with Python, getting in-depth with developing custom tools for the Processing Toolbox. The second module QGIS Blueprints gives you an overview of the application types and the technical aspects along with few examples from the digital humanities. After estimating unknown values using interpolation methods and demonstrating visualization and analytical techniques, the module ends by creating an editable and data-rich map for the discovery of community information. The third module QGIS 2 Cookbook covers data input and output with special instructions for trickier formats. Later, we dive into exploring data, data management, and preprocessing steps to cut your data to just the important areas. At the end of this module, you will dive into the methods for analyzing routes and networks, and learn how to take QGIS beyond the out-of-the-box features with plug-ins, customization, and add-on tools. This Learning Path combines some of the best that Packt has to offer in one complete, curated package. It includes content from the following Packt products: ? Learning QGIS, Third Edition by Anita Graser ? QGIS Blueprints by Ben Mearns ? QGIS 2 Cookbook by Alex Mandel, Víctor Olaya Ferrero, Anita Graser, Alexander Bruy
Table of Contents (6 chapters)

Chapter 3. Common Data Preprocessing Steps

In this chapter, we will cover the following recipes:

  • Converting points to lines to polygons and back – QGIS
  • Converting points to lines to polygons and back – SpatiaLite
  • Converting points to lines to polygons and back – PostGIS
  • Cropping rasters
  • Clipping vectors
  • Extracting vectors
  • Converting rasters to vectors
  • Converting vectors to rasters
  • Building DateTime strings
  • Geotagging photos

Introduction

When working with other people's data, it is often not the exact format that you need for a particular use. This chapter is all about taking the data that you do have and converting it to what you actually need. It covers converting between different types of vectors (points, lines, and polygons), between vectors and polygons, and cutting out only the parts that you need. Taking data from how you get it and converting it to the format and layout that you need in order to work with is often called 'data preprocessing'.

Converting...