Book Image

OpenLayers Cookbook

Book Image

OpenLayers Cookbook

Overview of this book

Data visualization and analysis has become an important task for many companies. Understanding the basic concepts of GIS and knowing how to visualize data on a map is a required ability for many professionals today. OpenLayers is a JavaScript library to load, display, and render maps from multiple sources on web pages."OpenLayers Cookbook" teaches how to work with OpenLayers, one of the most important and complete open source JavaScript libraries.Through an extensive set of recipes, this book shows how to work with the main concepts required to build a GIS web applicationñ maps, raster and vector layers, styling, theming, and so on."OpenLayers Cookbook" includes problem solving and how-to recipes for the most common and important tasks. A wide range of topics are covered.The range of recipes includes: creating basic maps, working with raster and vector layers, understanding events and working with main controls, reading features from different data sources, styling features, and understanding the underlying architecture."OpenLayers Cookbook" describes solutions and optimizations to problems commonly found.
Table of Contents (15 chapters)
OpenLayers Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Introduction


This chapter is all about working with raster layers. We have tried to summarize, with a set of recipes, the most common and important use cases you can find day-to-day when working with OpenLayers.

Imagery is one of the most important kinds of data to work with in a GIS system.

OpenLayers offers several classes to integrate with different imagery providers, from proprietary providers such as Google Maps and Bing Maps, to Open Source ones such as OpenStreetMap or even any WMS service provider.

The base class for any layer type is the OpenLayers.Layer class, which offers a set of common properties and defines the common behavior for any other classes.

In addition, many layers inherit from the OpenLayers.Layer.Grid class, which divides the layer into zoom levels. This way each zoom level covers the same area but uses a greater set of tiles. For example, at level zero a grid with one tile covers the whole world, at level one a grid with four tiles covers the whole world, and so on...