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

Vector sources


The vector layer class by itself isn't very useful—it relies on other classes to do all the interesting work. Let's look at the source class, ol.source.vector, and its subclasses first as it's the only thing that is absolutely needed to get a working vector layer.

The vector source class is named after its purpose—to be a source of vector features for a vector layer. It is responsible for fetching features when needed, providing them to the vector layer for rendering, and also for retrieving features based on various criteria. We won't actually use the vector source class as it is a base class for the classes we'll actually be using, such as ol.source.GeoJSON in the preceding example. The following diagram shows how the vector source classes fit together in the OpenLayers architecture:

As you can see, there are quite a few classes in the OpenLayers library that deal with vector formats. The classes that you can create new objects from are highlighted in green. We'll briefly...