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

Making an animation with image layers


When working with geographic information, its geometrical representation within the space is not the only important thing. Day by day time is becoming a new and important dimension to take into account.

This way, visualizations must show how data changes over time: city population, country frontiers, roads built, and so on.

There are many solutions to animate the data evolution through time but, as always, we work with web technologies, there are two groups: the solutions based on the server side and those based on the client side.

For server-side solutions, we can find the TIME parameter in the WMS and WFS standards. It allows us to request for raster or vector data in a specific time or within a range.

Server solutions means the client must request the server every time we want to show the data for a different interval.

For the client side, a simple solution is to have in the memory all the data, and only show those that correspond to the interval we are...