Book Image

OpenLayers 3: Beginner's Guide

By : Thomas Gratier, Paul Spencer, Erik Hazzard
Book Image

OpenLayers 3: Beginner's Guide

By: Thomas Gratier, Paul Spencer, Erik Hazzard

Overview of this book

<p>This book is a practical, hands-on guide that provides you with all the information you need to get started with mapping using the OpenLayers 3 library.</p> <p>The book starts off by showing you how to create a simple map. Through the course of the book, we will review each component needed to make a map in OpenLayers 3, and you will end up with a full-fledged web map application. You will learn the key role of each OpenLayers 3 component in making a map, and important mapping principles such as projections and layers. You will create your own data files and connect to backend servers for mapping. A key part of this book will also be dedicated to building a mapping application for mobile devices and its specific components.</p>
Table of Contents (22 chapters)
OpenLayers 3 Beginner's Guide
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Time for action – extending ol.control.Control to make your own control


Let's get started. Contrary to most examples, it will need more code than usual. So, to keep things simple, we will explain how to build the sample by retrieving the various code files instead of inlining it. After these operations, we will focus on the important parts of the code to understand them:

  1. Go to the samples directory and retrieve all the css class with the export-geojson string from assets/css/samples.css and copy paste them in your own samples.css file. Next, retrieve a new JavaScript file from https://github.com/eligrey/FileSaver.js/blob/master/FileSaver.js into a new subdirectory, assets/js.

  2. If you don't already have it from Chapter 8, Interacting with Your Map, go to download the features.geojson file from assets/data/features.geojson, within the book samples.

  3. Then, retrieve the code from chapter09/2360OS_09_06_custom_control.html.

  4. Finally, run node index.js, open your browser, and draw something. Push on...