Mastering QGIS - Second Edition

Kurt Menke, GISP, Dr. Richard Smith Jr., GISP, Dr. Luigi Pirelli, Dr. John Van Hoesen, GISP

• Publisher: Packt Publishing
• Year: 2016
• ISBN:
  9781786463623
• Edition: 2
• Topic: Computer Science
• Subtopic: Data Visualisation
• Index: Computer Science

Go beyond the basics and unleash the full power of QGIS with practical, step-by-step examplesAbout This Book• This book is your one-stop solution to all of your GIS needs using the open source QGIS• Master QGIS by learning about database integration, geoprocessing tools, Python scripts, advanced cartography, and custom plugins• This example-rich, practical guide will help you create sophisticated analyses and mapsWho This Book Is ForIf 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.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 pluginIn DetailQGIS is an open source solution to GIS. It is widely used by GIS professionals all over the world. It is the leading alternative to the 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, this book will take you all the way through to creating your first custom QGIS plugin. From the refresher, we will recap how to create, populate, and manage a spatial database. You'll also walk through styling GIS data, from creating custom symbols and color ramps to using blending modes. In the next section, you will discover how to prepare vector, heat maps, and create live layer effects, labeling, and raster data for processing. You'll also discover advanced data creation and editing techniques.The last third of the book covers the more technical aspects of QGIS such as using LAStools and GRASS GIS's integration with the Processing Toolbox, how to automate workflows with batch processing, and how to create graphical models. Finally, you will see how to create and run Python data processing scripts and write your own QGIS plugin with pyqgis.By the end of the book, you will understand how to work with all the aspects of QGIS, and will be ready to use it for any type of GIS work.Style and approachThis step-by-step comprehensive guide will let you dig your teeth into working with spatial databases, creating your own QGIS plugins, and creating your own custom graphical models.

Mastering QGIS - Second Edition

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Table of Contents

Mastering QGIS - Second Edition

Credits

Foreword

About the Authors

About the Reviewer

www.PacktPub.com

eBooks, discount offers, and more

Why subscribe?

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Downloading the color images of this book

Errata

Piracy

Questions

1. A Refreshing Look at QGIS

Release schedules

QGIS download and installation

Installing QGIS on Windows

Installing QGIS on Mac OS X

Installing QGIS on Ubuntu Linux

Installing QGIS only

Installing QGIS and other FOSSGIS packages

Installing QGIS on a Chromebook

Tour of QGIS

Familiarizing yourself with QGIS Desktop

User interface themes

Familiarizing yourself with QGIS Browser

Loading data into QGIS Desktop

Loading vector data

Loading raster data

Loading databases

Loading web services

Working with CRS

Working with tables

Creating table joins

Editing data

Snapping

Styling vector data

Styling raster data

Enhancing raster display with contrast enhancement

Blending modes

Composing maps

Adding functionality with plugins

Custom QGIS variables

Using Project level variables in the Print Composer

Using variables in data defined overrides

Using Layer level variables

Summary

2. Creating Spatial Databases

Fundamental database concepts

Describing database tables

Knowing about table relationships

Reviewing the basics of Structured Query Language

Creating a spatial database

Importing data into a SpatiaLite database

Importing KML into SpatiaLite

Importing a shapefile into SpatiaLite

Importing tables into SpatiaLite

Exporting tables out of SpatiaLite

Managing tables

Creating a new table

Renaming a table

Editing table properties

Deleting a table

Emptying a table

Creating queries and views

Creating a SQL query

Creating a spatial view

Dropping a spatial view

Summary

3. Styling Raster and Vector Data

Choosing and managing colors

Always-available color picker components

Changeable panels in color picker

Color ramp

Color wheel

Color swatches

Color sampler

Color picker components available in the Layers panel

Managing color ramps

Managing the QGIS color ramp collection

Renaming a color ramp

Removing a color ramp

Exporting a color ramp

Importing a color ramp

Adding a color ramp

Adding a Gradient color ramp

Adding a Random color ramp

Adding a ColorBrewer color ramp

Adding a cpt-city color ramp

Editing a color ramp

Styling singleband rasters

Paletted raster band rendering

Singleband gray raster band rendering

Singleband pseudocolor raster band rendering

Styling multiband rasters

Creating a raster composite

Raster color rendering

Raster resampling

Styling vectors

Single-symbol vector styling

Categorized vector styling

Graduated vector styling

Rule-based vector styling

Point-displacement vector styling

Inverted polygons vector styling

Heatmap vector styling

2.5 D vector styling

Vector layer rendering

Layer transparency

Layer blending mode

Feature blending mode

Control feature rendering order

Using diagrams to display thematic data

Parameters common to all diagram types

Diagram size parameters

Diagram placement parameters

Adding attributes to diagrams

Creating a pie chart diagram

Creating a text diagram

Creating a histogram chart diagram

Saving, loading, and setting default styles

Saving a style

Loading a style

Setting and restoring a default style

Adding and renaming styles in the current QGIS project

Summary

4. Preparing Vector Data for Processing

Merging shapefiles

Creating spatial indices

Checking for geometry errors

Check Geometries plugin

Converting vector geometries

Creating polygon centroids

Converting polygons to lines and lines to polygons

Creating polygons surrounding individual points

Extracting nodes from lines and polygons

Simplifying and densifying features

Converting between multipart and singlepart features

Adding geometry columns to an attribute table

Using basic vector geoprocessing tools

Spatial overlay tools

Using the Clip and Difference tools

Using the Intersect and Symmetrical Difference tools

Overlaying polygon layers with Union

Creating buffers

Generating convex hulls

Dissolving features

Defining coordinate reference systems

Understanding the PROJ.4 definition format

Defining a new custom coordinate reference system

Viewing a statistical summary of vector layers

Advanced field calculations

Exploring the field calculator interface

Writing advanced field calculations

The first example – calculating and formatting current date

The second example – calculating with geometry

The third example – calculating a population-dependent label string

Conditional formatting for attribute table cells

Complex spatial and aspatial queries

Summary

5. Preparing Rast...