Mastering OpenLayers 3

Gabor Farkas

• Publisher: Packt Publishing
• Year: 2016
• ISBN:
  9781785281006
• Edition: 1
• Topic: Informatica
• Subtopic: Servizi web e API

Create powerful applications with the most robust open source web mapping library using this advanced guide

About This Book

• Develop responsive and platform-independent web mapping applications with OpenLayers 3
• Learn the key points of creating great applications with native JavaScript through the step-by-step examples
• Master the use of the library, from compiling custom builds to developing a complete WebGIS application

Who This Book Is For

This book is intended for front-end developers with basic understanding of JavaScript and GIS concepts, and preferably for those who are familiar with the fundamentals of OpenLayers 3. You might have never used OpenLayers 3 as a seasoned JavaScript developer. If this is the case and you are eager to learn web mapping, this book will definitely set you on the right track.

What You Will Learn

• Use the advanced functionality of the OpenLayers 3 library effectively
• Implement the library in your application, shaping it to your needs
• Manage layers and the layer stack dynamically
• Create not only stunning but also accurate thematic maps
• Extend OpenLayers 3 with your own custom classes
• Develop mobile-friendly web mapping applications
• Make stunning effects with canvas manipulation, or visualize point clouds with WebGL
• Integrate third-party applications, and create custom builds that completely satisfy your needs

In Detail

OpenLayers 3 allows you to create stunning web mapping and WebGIS applications. It uses modern, cutting edge browser technologies. It is written with Closure Library, enabling you to build browser-independent applications without painful debugging ceremonies, which even have some limited fallback options for older browsers.

With this guide, you will be introduced to the world of advanced web mapping and WebGIS.

First, you will be introduced to the advanced features and functionalities available in OpenLayers 3. Next, you will be taken through the key points of creating custom applications with OpenLayers 3. You will then learn how to create the web mapping application of yours (or your company's) dream with this open source, expense-free, yet very powerful library. We'll also show you how to make amazing looking thematic maps and create great effects with canvas manipulation.

By the end of this book, you will have a strong command of web mapping and will be well on your way to creating amazing applications using OpenLayers 3.

Style and approach

This is an advanced guide packed with comprehensive examples, and it concentrates on the advanced parts of OpenLayers 3 and JavaScript. It intentionally skips the basic and well-known methodologies, but discusses the hard-to-understand ones in great detail.

Mastering OpenLayers 3

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Table of Contents

Mastering OpenLayers 3

Credits

About the Author

About the Reviewer

www.PacktPub.com

Support files, eBooks, discount offers, and more

Why subscribe?

Free access for Packt account holders

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. Creating Simple Maps with OpenLayers 3

Before getting started

Creating a working environment

Structure of OpenLayers 3

Building the layout

Creating the appeal

Writing the code

Using the API documentation

Understanding type definitions

Debugging the code

Summary

2. Applying Custom Styles

Before getting started

Basic considerations

Customizing the default appearance

Identifying the classes

Styling the controls

Customizing the attribution control

Creating a custom zoom control with CSS

Styling vector layers

Customizing the appearance with JavaScript

Changing the overview map and the scale bar

Truncating the coordinate control

Changing the attribution

Creating a WebGIS client layout

Building the HTML

Styling the layout

Writing the code

Summary

3. Working with Layers

Before getting started

Using a proxy

Resources to use

Basic considerations

Building a layer tree

Styling the layer tree

Creating a layer tree constructor

Adding layers dynamically

Creating the interface

Extending the constructor

Fetching the WMS metadata

Adding WMS layers

Adding WFS layers

WFS considerations

Adding vector layers with the File API

Creating the interface

Building the method

Adding vector layers with a library

Removing layers dynamically

Extending a constructor

Changing layer attributes

Styling active layers

Extending the method

Changing the layer order with the Drag and Drop API

Clearing the message bar

Summary

4. Using Vector Data

Before getting started

Accessing attributes

Writing the code

Setting attributes

Styling the form

Writing the code

Validating attributes

Adjusting the styles

Building headers

Writing the code

Creating thematic layers

Extending the layer tree

Creating choropleth maps

Creating categorized maps

Saving vector data

Saving in arbitrary formats

Saving with WFS-T

Modifying the geometry

Summary

5. Creating Responsive Applications with Interactions and Controls

Before getting started

Basic considerations

Building the toolbar

Mapping interactions to controls

Creating the control

Adding and removing the control

Adding a selection control

Building a set of feature selection controls

Styling the controls

Creating the selection tools

Adding new vector layers

Creating the HTML and the CSS

Extending the layer tree

Building a set of drawing tools

Writing the method

Modifying and snapping to features

Extending the method

Creating new interactions

Understanding ol.interaction.Pointer

Removing features

Dragging features

Extending the method

Building a measuring control

Creating the interaction

Doing geodesic measurements

Calculating lengths even more precisely

Summary

6. Controlling the Map – View and Projection

Before getting started

Basic considerations

Customizing a view

Constraining a view

Creating a navigation history

Working with extents

Creating a zoom control

Extending the toolbar

Rotating a view

Changing the map's projection

Creating custom animations

Building the control

Creating animations

Summary

7. Mastering Renderers

Before getting started

Using different renderers

Creating a WebGL map

Drawing lines and polygons with WebGL

Blending layers

Clipping layers

Exporting a map

Creating a raster calculator

Raster 101

Operating with pixels

Creating a convolution matrix

How convolution works

Converting an image to 8-bit

Implementing the Sobel filter

Normalizing an image

Finalizing a control

Clipping a layer with WebGL

Writing programs

Creating a clipping mask

Summary

8. OpenLayers 3 for Mobile

Before getting started

Basic considerations

Responsive styling with CSS

Writing the style sheet

Constructing the map

Generating geocaches

Adding device-dependent controls

Adding controls for touch devices

Adding controls for desktop computers

Vectorizing the mobile version

Making the mobile application interactive

Summary

9. Tools of the Trade – Integrating Third-Party Applications

Before getting started

Exporting a QGIS project

Installing the qgis2web plugin

Inspecting the project

Exporting a map

Salvaging the results

Importing shapefiles

Editing the HTML file

Replacing a function

Spatial analysis with Turf

Preparing an example

Implementing a buffer operation

Implementing a merge operation

Implementing the self-intersect operation

Spatial analysis with JSTS

Implementing operations

3D rendering with Cesium

Preparing a map

Creating a control

Observing a terrain

Extending the Cesium scene

Summary

10. Compiling Custom Builds with Closure

Before getting started

Configuring Node JS

Installing Node JS on Windows

Installing Node JS on Linux

Resolving dependencies

Compiling OpenLayers 3

Building default versions

Understanding a configuration file

Building OpenLayers 3 with a subset of features

Bundling an application with OpenLayers 3

Editing the application

Creating a configuration file

Fixing the application

Extending OpenLayers 3

Creating rich documentation with JSDoc

Customizing the documentation

Summary

Index

Mastering OpenLayers 3

Copyright © 2016 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: January 2016

Production reference: 1220116

Published by Packt Publishing Ltd.

Livery Place

35 Livery Street

Birmingham B3 2PB, UK.

ISBN 978-1-78528-100-6

www.packtpub.com

Credits

Author

Gábor Farkas

Reviewer

Jose Troche

Commissioning Editor

Veena Pagare

Acquisition Editor

Sonali Vernekar

Content Development Editor

Anish Dhurat

Technical Editor

Jayesh Sonawane

Copy Editors

Sonia Cheema

Trishya Hajare

Project Coordinator

Bijal Patel

Proofreader

Safis Editing

Indexer

Monica Ajmera Mehta

Graphics

Disha Haria

Production Coordinator

Conidon Miranda

Cover Work

Conidon Miranda

About the Author

Gábor Farkas is a PhD student at University of Pécs's Institute of Geography. He holds a master's degree in geography, although he moved from traditional geography to pure Geoinformatics early in his academic journey. He often studies Geoinformatical solutions in his free time, keeps up with the latest trends, and is an open source enthusiast. He loves to work with GRASS GIS, PostGIS, and QGIS, but his all-time favorites a...

Table of contents

• Mastering OpenLayers 3