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  • Book Overview & Buying OpenLayers 2.10 Beginner's Guide
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OpenLayers 2.10 Beginner's Guide

OpenLayers 2.10 Beginner's Guide

By : Erik Hazzard
4.2 (9)
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OpenLayers 2.10 Beginner's Guide

OpenLayers 2.10 Beginner's Guide

4.2 (9)
By: Erik Hazzard

Overview of this book

This is a beginner's guide with the essential screenshots and clearly explained code, which also serves as a reference. This book is for anyone who has any interest in using maps on their website, from hobbyists to professional web developers. OpenLayers provides a powerful, but easy-to-use, pure JavaScript and HTML (no third-party plug-ins involved) toolkit to quickly make cross-browser web maps. A basic understanding of JavaScript will be helpful, but there is no prior knowledge required to use this book. If you've never worked with maps before, this book will introduce you to some common mapping topics and gently guide you through the OpenLayers library. If you're an experienced application developer, this book will also serve as a reference to the core components of OpenLayers.
Table of Contents (18 chapters)
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OpenLayers 2.10
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
1
Index

Map projections


No maps of the earth are truly perfect representations; all maps have some distortion. The reason for this is because they are attempting to represent a three dimensional object (an ellipsoid: the earth) in two dimensions (a plane: the map itself).

A projection is a representation of the entire, or parts of a, surface of a three dimensional sphere on a two dimensional plane (or other type of geometry).

Why on earth are Projections used?

Every map has some sort of projection—it is an inherent attribute of maps. Imagine unpeeling an orange and then flattening the peel out. Some kind of distortion will occur, and if you try to fully fit the peel into a square or rectangle (like a flat, two dimensional map), you'd have a very hard time.

To get the peel to fit perfectly onto a flat square or rectangle, you could try to stretch out certain parts of the peel or cut some pieces of the peel off and rearrange them. The same sort of idea applies while trying to create a map.

There are literately...

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83
Tech Concepts
36
Programming languages
73
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OpenLayers 2.10 Beginner's Guide
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