What do you get with Print?

Instant access to your digital copy whilst your Print order is Shipped

Paperback book shipped to your preferred address

Redeem a companion digital copy on all Print orders

Access this title in our online reader with advanced features

DRM FREE - Read whenever, wherever and however you want

Mastering QGIS

Chapter 1. A Refreshing Look at QGIS

QGIS is a volunteer-led development project licensed under the GNU General Public License. It was started by Gary Sherman in 2002. The project was incubated with the Open Source Geospatial Foundation (OSGeo) in 2007. Version 1.0 was released in 2009. At the time of writing this book, QGIS 2.6 was the stable version and new versions are released every four months.

In this chapter we will review the basic functionality of QGIS, which will be assumed knowledge for the remaining chapters in this book. If you need a refresher on QGIS or a quick-start 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
Working with tables
Editing data
Styling data
Composing a map
Finding and installing plugins

QGIS download and installation

QGIS can be installed on Windows, Mac OS X, 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, Mac OS X, and Ubuntu Linux. For the most up-to-date installation instructions, refer to the QGIS website.

Installing QGIS on Windows

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.
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.

Installing QGIS on Mac OS X

To install QGIS on Mac OS X, the Geospatial Data Abstraction Library (GDAL) framework and matplotlib Python module must be installed first, followed by the QGIS installation. The installation files for GDAL, matplotlib, and QGIS are available at http://www.kyngchaos.com/software/qgis.

Installing QGIS on Ubuntu Linux

There are two options when installing QGIS on Ubuntu: installing QGIS only, or installing QGIS as well as other 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 current release's 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

Note

QGIS is also available for Android. We have not provided detailed installation instructions because it is in alpha testing at the moment. However, there are plans to have a normalized installation process in a future release. You can find more information about this at http://hub.qgis.org/projects/android-qgis.

The download page is available at http://qgis.org/downloads/android/.

A related app has recently been announced and it is named QField for QGIS. For a short time, it was named QGIS Mobile. It is described as a field data capture and management app that is compatible with QGIS. At the time of writing this, it was in invite-only alpha testing. It is eventually expected to be available in the Android Play Store. You can find more information on this app at http://www.opengis.ch/tech-blog/.

Tour of QGIS

QGIS is composed of two programs: QGIS Desktop and QGIS Browser. Desktop is used for managing, displaying, analyzing, and styling data. Browser is used to manage and preview data. This section will give you a brief tour of the graphical user interface components of both QGIS Desktop and QGIS Browser.

QGIS Desktop

The QGIS interface is divided into four interface types: menu bar, toolbars, panels, and map display. The following screenshot shows QGIS Desktop with all four interface types displayed:

The map display shows the styled data added to the QGIS project and, by default, takes up the majority of the space in QGIS Desktop. The menu bar, displayed across the top, provides access to most of QGIS Desktop's functionality. The toolbars provide quick access to QGIS Desktop functionality. The toolbars can be arranged to either float independently or dock at the top, bottom, left, or right sides of the application. The panels, such as Browser and Layers, provide a variety of functionality and can be arranged to either float independently or dock above, below, right, or left of the map display.

There are four toolbars that are particularly useful, and it is recommended that you enable them:

The File toolbar provides quick access to create, open, and save QGIS projects and create and manage print composers
The Manage Layers toolbar contains tools to add vector, raster, database, web service, text layers, and create new layers
The Map Navigation toolbar contains tools that are useful for panning, zooming, and refreshing the map display
The Attributes toolbar provides access to information, selection, field calculator, measuring, bookmarking, and annotation tools

QGIS Desktop offers a number of customization options. You can toggle the visibility of toolbars by navigating to View | Toolbars, or by right-clicking on the menu bar or the enabled toolbar button, which will open a context menu allowing you to toggle the toolbar and panel visibility. You can assign shortcut keys to operations by navigating to Settings | Configure shortcuts. You can also change application options, such as interface language and rendering options by navigating to Settings | Options.

QGIS Browser

The QGIS Browser interface (shown in the following screenshot) is composed of three parts: toolbar, data tree view, and information panel.

The data tree view is an expandable tree listing of all geospatial data files on your computer and through connections. The information display, which takes most of the space on the application, contains four tabs that provide different views of the selected data in the data tree listing, and they are as follows:

Param: This tab displays details of data that is accessed through connections, such as a database or WMS.
Metadata: This tab displays the metadata (if any) of the selected data.
Preview: This tab renders the selected data. You can zoom into the data using your mouse wheel and pan using the arrow keys on your keyboard.
Attribute: This tab displays the attribute table associated with the selected data. You can sort the columns by clicking on the column headings.

The toolbar provides access to four functions. The Refresh function reloads the data tree view while the Manage WMS function opens the WMS management screen allowing you to manage the WMS connections. The New Shapefile function opens the new vector layer dialog allowing new shapefiles to be created. Finally, the Set layer CRS function allows you to define the coordinate reference system of the geospatial data file that is selected in the data tree view.

Loading data

One strength of QGIS is its ability to load a large number of data types. In this section, we will cover loading various types of data into QGIS Desktop.

In general, data can be loaded in four ways. The first way, which will be covered in detail in this section, is to use the Add Layer menu under Layer and select the appropriate type of data that you wish to load. The second way is to open the Browser panel, navigate to the data you wish to load, and then drag the data onto the map display or onto the Layers panel. The third way to load data is to enable the Manage Layers toolbar and click on the button representing the data type that you wish to load. The fourth way is to locate the data in QGIS Browser, drag the data, and drop it onto the QGIS Desktop map display or the Layers panel.

Loading vector data

To load vector files, click on Add Vector Layer by navigating to Layer | Add Layer. This will open the Add Vector Layer dialog that will allow us to choose the source type and source of the dataset that we wish to load.

The source type contains four options: File, Directory, Database, and Protocol. When you choose a source type, the source interface will change to display the appropriate options. Let's take a moment to discuss what type of data these four source types can load:

File: This can load flat files that are stored on disk. The commonly used flat file types are as follows:
- ESRI shapefile (.shp)
- AutoCAD DXF (.dxf)
- Comma separated values (.csv)
- GPS eXchange Format (.gpx)
- Keyhole Markup Language (.kml)
- SQLite/SpatiaLite (.sqlite/.db)
Directory: This can load data stored on disk that is encased in a directory. The commonly used directory types are as follows:
- U.S. Census TIGER/Line
- Arc/Info Binary Coverage
Database: This can load databases that are stored on disk or those available through service connections. The commonly used database types are as follows:
- ODBC
- ESRI Personal GeoDatabase
- MSSQL
- MySQL
- PostgreSQL
Protocol: This can load protocols that are available at a specific URI. QGIS currently supports loading the GeoJSON protocol.

Loading raster data

To load raster data into QGIS, click on Add Raster Layer by navigating to Layer | Add Layer. This will open a file browser window and allow you to choose a GDAL-supported raster file. The commonly used raster types supported by GDAL are as follows:

ArcInfo ASCII Grid (.asc)
Erdas Imagine (.img)
GeoTIFF (.tif/.tiff)
JPEG/JPEG-2000 (.jpg or .jpeg/.jp2 or .j2k)
Portable Network Graphics (.png)
Rasterlite (.sqlite)
USGS Optional ASCII DEM (.dem)

To add an Oracle GeoRaster, click on Add Oracle GeoRaster Layer by navigating to Layer | Add Layer, then connect to an Oracle database to load the raster. More information about loading database layers is in the following section.

Note

The Geospatial Data Abstraction Library (GDAL) is a free and open source library that translates and processes vector and raster geospatial data formats. QGIS, as well as many other programs, use GDAL to handle many geospatial data processing tasks.

You may see references to OGR or GDAL/OGR as you work with QGIS and GDAL. OGR is short for OGR Simple Features Library and references the vector processing parts of GDAL. OGR is not really a standalone project, as it is part of the GDAL code now; however, for historical reasons, OGR is still used.

More information about GDAL and OGR can be found at http://gdal.org. GDAL is an Open Source Geospatial Foundation (http://osgeo.org) project.

Loading databases

QGIS supports PostGIS, SpatiaLite, MSSQL, and Oracle databases. Regardless of the type of database you wish to load, the loading sequence is very similar. Therefore, instead of covering specific examples, the general sequence will be covered.

First, click on Add Layer under Layer and then choose the database type you wish to load. This will open a window with options for adding the data stored in a database. As an example, the following screenshot shows the window that opens when you navigate to Layer | Add Layer | Add SpatiaLite Layer:

Note

Note that the window will look the same for any database you choose, except for the window name.

To load data from a database, we must first create a connection to the database. To create a new connection, click on the New button to open a connection information window. Depending on the database type you are connecting to, different connection options will be shown. Once you have created a database connection, select it from the drop-down list and click on Connect; you will see a list of all layers contained within the database display. If there are a large number of tables, you can select Search options and perform a search on the database. To load a layer, select it in the list and click on Add. If you only wish to load a portion of the layer, select the layer and then click on Set Filter to open the query builder. If you set a query and then add the layer, only the filtered features will be added.

Web services

QGIS supports the loading of OGC-compliant web services such as WMS/WMTS, WCS, and WFS. Loading a web service is similar to loading a database service. In general, you will create a new server connection, connect to the server to list the available services, and add the service to the QGIS project.

Working with coordinate reference systems

When working with spatial data, it is important that a coordinate reference system (CRS) is assigned to the data and the QGIS project. To view the CRS for the QGIS project, click on Project Properties under Project and choose the CRS tab.

It is recommended that all data added to a QGIS project be projected into the same CRS as the QGIS project. However, if this is not possible or convenient, QGIS can project layers "on the fly" to the project's CRS.

Note

If you want to quickly search for a CRS, you can enter the EPSG code to quickly filter through the CRS list. An EPSG code refers to a specific CRS stored in the EPSG Geodetic Parameter Dataset online registry that contains numerous global, regional, and local CRS. An example of a commonly used EPSG code is 4326 that refers to WGS 84. The EPSG online registry is available at http://www.epsg-registry.org/.

To enable the "on the fly" projection, perform the following steps:

Click on Project Properties under Project.
Choose the CRS tab and Enable 'on the fly' CRS transformation.
Set the CRS that you wish to apply to the project and make all layers that are not set to the project's CRS transform "on the fly".

To view the CRS for a layer, perform the following steps:

Open the layer's properties by either navigating to Layer | Properties or by right-clicking on the layer in the Layers panel.
Choose Properties from the context menu and then choose the General tab.
If the layer's CRS is not set or is incorrect, click on Specify to open the CRS selector window and select the correct CRS.

To project a layer to a different CRS, perform the following steps:

Right-click on the layer in the Layers panel and then choose Save As from the context menu.
In the Save vector layer as dialog, set the file format and filename, then set CRS to Selected CRS and click on Change to set the target CRS, and save the file.

To create a new CRS or modify an existing CRS, perform the following steps:

Click on Custom CRS under Settings to open the Custom Coordinate Reference System Definition window.
Click on the Add new CRS button to add a new entry to the CRS list.
With the new CRS selected, we can set the name and parameters of the CRS. The CRS properties are set using the Proj.4 format. To modify an existing CRS, click on Copy existing CRS and select the CRS from which you wish to copy parameters; otherwise, enter the parameters manually.
Tip
Proj.4 is another Open Source Geospatial Foundation (http://osgeo.org) project used by QGIS, and it is similar to OGR and GDAL. This project is for managing coordinate systems and projections. For a detailed user manual for the Proj.4 format used to specify the CRS parameters in QGIS, download it from ftp://ftp.remotesensing.org/proj/OF90-284.pdf.

What you will learn

Create and manage a spatial database

Learn advanced techniques to style GIS data

Prepare both vector and raster data for processing

Understand how to work 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 plugin

What do you get with Print?

Instant access to your digital copy whilst your Print order is Shipped

Paperback book shipped to your preferred address

Redeem a companion digital copy on all Print orders

Access this title in our online reader with advanced features

DRM FREE - Read whenever, wherever and however you want

Frequently bought together

€36.99

€41.99

€41.99

Total € 120.97

Filter reviews by

All

Amazon verified reviews

hawoni Jun 17, 2015

I'm sometimes hesitant to try a new tool if I'm not sure what all the parameters mean, so for me this book is a great way to avoid getting sucked into hours of research and outdated information. Also, as a visual learner I appreciate all the screenshots of QGIS in action.

Amazon Verified review

Kerrie Bushway May 12, 2015

One of the frustrations in my quest to learn Open Source GIS software is the haphazard documentation, or documentation which is geared toward programmers and developers. This book, along with Anita Graser's Learning QGIS, is exactly what is needed for my knowledge level where I know GIS, but I'm not a code nerd (which I hope to change.) Mastering QGIS is a comprehensive work that covers more advanced analysis scenarios with easy to understand directions, but it never falls into the boring, exceedingly detailed "Now click this" for every single step. The authors understand the book's intended audience, which I appreciated. The lack of color in the print book didn't detract from what the book had to offer - the ebook version has full color images. I've already highlighted and post-it-noted my copy copiously for future reference. With the knowledge in this book, any GIS user could approach the power of a certain proprietary GIS software package. A must-have for any QGIS user!

K. König E. Fisel Aug 25, 2015

..und gut gewählte Beispiele wie der graph. Modellierer zum Automatisieren von GIS-Arbeiten und das Arbeiten mit den Tools von GRASS, SAGA und TauDEM

liz Mar 26, 2016

using friendly and clear.

Lara Wood Miller Apr 15, 2015

I have been a GIS professional for 20 years, mostly using ESRI software. I recently started my own company and needed to become proficient with QGIS quickly for a contract. This book is comprehensive and well-written and helped me develop a solid foundation with QGIS in a very short amount of time. I would recommend it highly to professionals wanting to expand their skill set into the open source GIS software arena.

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

What do you get with Print?

Mastering QGIS

Chapter 1. A Refreshing Look at QGIS

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

Note

Tour of QGIS

QGIS Desktop

QGIS Browser

Loading data

Loading vector data

Loading raster data

Note

Loading databases

Note

Web services

Working with coordinate reference systems

Note

Tip

Page 1 of 10

Description

Who is this book for?

What you will learn

Product Details

What do you get with Print?

Product Details

Frequently bought together

Table of Contents

Recommendations for you

Customer reviews

Filter reviews by

People who bought this also bought

About the author

FAQs

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

What do you get with Print?

Contact Details

Shipping Address

Billing Address

Installing QGIS on Windows

Installing QGIS on Mac OS X

Installing QGIS on Ubuntu Linux

Installing QGIS only

Installing QGIS and other FOSSGIS Packages

Note

Tip

Description

Who is this book for?

What you will learn

Product Details

What do you get with Print?

Contact Details

Shipping Address

Billing Address

Product Details

Packt Subscriptions

Frequently bought together

Table of Contents

Recommendations for you

Customer reviews

Filter reviews by

People who bought this also bought

About the author

FAQs