Mastering Geospatial Development with QGIS 3.x

An in-depth guide to becoming proficient in spatial data analysis using QGIS 3.4 and 3.6 with Python, 3rd Edition

Shammunul Islam, Simon Miles, Luigi Pirelli

• Publisher: Packt Publishing
• Year: 2019
• ISBN:
  9781788994873
• Edition: 3
• Topic: Computer Science
• Subtopic: Data Visualisation
• Index: Computer Science

Go beyond the basics and unleash the full power of QGIS 3.4 and 3.6 with practical, step-by-step examples

Key Features

• One-stop solution to all of your GIS needs
• Master QGIS by learning about database integration, and geoprocessing tools
• Learn about the new and updated Processing toolbox and perform spatial analysis

Book Description

QGIS is an open source solution to GIS and widely used by GIS professionals all over the world. It is the leading alternative to proprietary GIS software. Although QGIS is described as intuitive, it is also, by default, complex. Knowing which tools to use and how to apply them is essential to producing valuable deliverables on time.

Starting with a refresher on the QGIS basics and getting you acquainted with the latest QGIS 3.6 updates, this book will take you all the way through to teaching you how to create a spatial database and a GeoPackage. Next, you will learn how to style raster and vector data by choosing and managing different colors. The book will then focus on processing raster and vector data. You will be then taught advanced applications, such as creating and editing vector data. Along with that, you will also learn about the newly updated Processing Toolbox, which will help you develop the advanced data visualizations. The book will then explain to you the graphic modeler, how to create QGIS plugins with PyQGIS, and how to integrate Python analysis scripts with QGIS.

By the end of the book, you will understand how to work with all aspects of QGIS and will be ready to use it for any type of GIS work.

What you will learn

• Create and manage a spatial database
• Get to know advanced techniques to style GIS data
• Prepare both vector and raster data for processing
• Add heat maps, live layer effects, and labels to your maps
• Master LAStools and GRASS integration with the Processing Toolbox
• Edit and repair topological data errors
• Automate workflows with batch processing and the QGIS Graphical Modeler
• Integrate Python scripting into your data processing workflows
• Develop your own QGIS plugins

Who this book is for

If you are a GIS professional, a consultant, a student, or perhaps a fast learner who wants to go beyond the basics of QGIS, then this book is for you. It will prepare you to realize the full potential of QGIS.

Section 1: Introduction

QGIS 3 is the first major new release of QGIS in several years. This section reviews what major changes will be treated as assumed knowledge for the remainder of the book.

This section contains the following chapter: 

• Chapter 1,  A Refreshing Look at QGIS

A Refreshing Look at QGIS

In this chapter, we will review the basic functionality of QGIS and explore some of the new features of versions starting from 3.4. If you need a refresher on QGIS or a quickstart guide to QGIS, you should read this chapter. The topics we will cover in this chapter are as follows:

• Downloading QGIS and its installation
• The QGIS graphical user interface
• Loading data
• Working with coordinate reference systems (CRS)
• Working with tables
• Editing data
• Styling data
• Composing a map
• Finding and installing plugins

QGIS is a volunteer-led development project licensed under the GNU General Public License, and was started by Gary Sherman in 2002. The project was incubated with the Open Source Geospatial Foundation (OSGeo) in 2007, with QGIS 1.0 being released in 2009. The continued development of QGIS is supported by an active and vibrant community from around the world. Many people assume that they can only help with the development of QGIS if they can perform computer programming, but this is false! QGIS has many community members that write documentation, test the program for bugs, translate documents, answer forum questions, and provide financial support. QGIS user groups exist as well, aiming to bring people together to share experiences of QGIS. It is easy to get involved, and the authors encourage you to consider contributing. Learn about how to get involved at http://qgis.org/en/site/getinvolved/.

Release schedules

Currently, a new version of QGIS is released around every four months. The version released each spring is designated as a long-term release (LTR). This means it will be supported for one calendar year. Each quarter, a new stable version is released and bug fixes applied to the LTR. The LTR is recommended for production environments since it has a slower release cycle. At the time of writing, QGIS 3.4.5 is the current LTR, with version 3.6 available for download.

It is possible to have multiple versions of QGIS installed on a single machine.

QGIS downloading and installation

QGIS can be installed on Windows, macOS, Unix, Linux, and Android operating systems, making it a very flexible software package. Both the binary installers and source code can be downloaded from download.qgis.org. In this section, we will briefly cover how to install QGIS on Windows, macOS, and Ubuntu Linux. For the most up-to-date installation instructions, refer to the QGIS website.

Installing QGIS on Windows

On the QGIS website, download the correct version of QGIS for your Windows machine. Downloadable executable files come in 32-bit and 64-bit flavors. We recommend downloading the latest release as advertised on the QGIS website download page.

For Windows, there are two installation options, which are as follows:

• QGIS Standalone Installer: The standalone installer installs the binary version of QGIS and the Geographic Resource Analysis Support System (GRASS) using a standard Windows installation tool. You should choose this option if you want an easy installation experience of QGIS. This is also the ideal installation method for organizations or businesses wishing to deploy QGIS to multiple users.

• OSGeo4W Network Installer: This provides you with the opportunity to download either the binary or source code version of QGIS, as well as experimental releases of QGIS. Additionally, the OSGeo4W installer allows you to install other open source tools and their dependencies.

If you are unsure on how to install QGIS, the QGIS website contains details on how to do this.

Installing QGIS on macOS

The QGIS website provides download mac installer packages for macOS, that contain readme files for the installation of QGIS. Documentation and support for QGIS on macOS has greatly improved, and while it is beyond the scope of this chapter to detail the install process and document any possible issues that might incur during installation, the GIS Stack Exchange (https://gis.stackexchange.com/) is a great refresh resource.

Installing QGIS on Ubuntu Linux

There are two options when installing QGIS on Ubuntu: installing QGIS only, or installing QGIS as well as other Free and Open Source Software for Geographical Information Systems (FOSSGIS) packages. Either of these methods requires the use of the command line, sudo rights, and the apt-get package manager.

Installing QGIS only

Depending on whether you want to install a stable release or an experimental release, you will need to add the appropriate repository to the /etc/apt/sources.list file.

With sudo access, edit /etc/apt/sources.list and add the following line to install the current stable release or the current release source code, respectively:

deb http://qgis.org/debian trusty main deb-src http://qgis.org.debian trusty main 

Depending on the release version of Ubuntu you are using, you will need to specify the release name as trusty, saucy, or precise. For the latest list of QGIS releases for Ubuntu versions, visit download.qgis.org.

With the appropriate repository added, you can proceed with the QGIS installation by running the following commands:

sudo apt-get update sudo apt-get install qgis python-qgis  

To install the GRASS plugin (recommended), install the optional package by running this command:

sudo apt-get install qgis-plugin-grass

Installing QGIS and other FOSSGIS packages

The ubuntugis project installs QGIS and other FOSSGIS packages, such as GRASS on Ubuntu. To install the ubuntugis package, remove the http://qgis.org/debian lines from the /etc/apt/sources.list file and run the following commands:

sudo apt-get install python-software-properties sudo add-apt-repository ppa:ubuntugis/ubuntugis-unstable sudo apt-get update sudo apt-get install qgis python-qgis qgis-plugin-grass

QGIS on Android

At the time of writing, there is really only one Android QGIS application available on Google Play, called QField, developed by OPENGIS.ch from Switzerland. Users of QGIS can save their projects to their Android device and then reopen them in QField. The application comes with Geolocation capabilities, data editing, and photos captured, to name just a few of its features.

Further information on QField can be found at http://www.qfield.org/docs/index.html.

While QField may currently (at the time of wr...

Table of contents

• Title Page
• Copyright and Credits
• About Packt
• Contributors
• Preface
• Section 1: Introduction
• A Refreshing Look at QGIS
• Section 2: Getting Started
• Styling Raster and Vector Data
• Creating Spatial Databases
• Preparing Vector Data for Processing
• Preparing Raster Data for Processing
• Section 3: Diving Deeper
• Advanced Data Creation and Editing
• Advanced Data Visualization
• Section 4: Becoming a Master
• The Processing Toolbox
• Automating Workflows with the Graphical Modeler
• Creating QGIS Plugins with PyQGIS and Problem Solving
• PyQGIS Scripting
• Other Books You May Enjoy