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

The DeviceOrientation class


Many new computers, and especially mobile phones and tablets, provide hardware support to track their orientation. The HTML 5 specification defines the DeviceOrientation API to expose this information. Just as with the Geolocation API, OpenLayers provides the ol.DeviceOrientation class to make it easier to work with this API in a stable, cross-browser compatible way.

Device orientation refers to the orientation of the mobile device relative to a common starting point. A device's orientation is then reported as angles of rotation from this common reference orientation. For mobile devices, the reference orientation is defined as the phone lying face up on a table with the top of the phone pointing north. For computers, it is the same, except the screen is open at 90 degrees. This represents the zero state, and all angles are reported relative to this state.

Device orientation is reported as three angles—alpha, beta, and gamma—relative to the starting orientation along...