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

Reading and creating features from a WKT


OpenLayers comes with a great set of format classes, which are used to read/write from/to different file data formats. GeoJSON, GML, or GPX are some of the many formats we can find.

If you have read the Adding a GML layer recipe in this chapter, you will know that a vector class can read the features stored in a file, specify the format of the data source, and place the contained features in the map.

This recipe wants to show us exactly that. We will see the magic step responsible to read data from a file using a format class, and transform it to the corresponding feature ready to be placed in the layer.

Note

For simplicity, we will only see how to read features from the WKT text. You can learn more about WKT (Well-Known Text) format from http://en.wikipedia.org/wiki/Well-known_text.

As can be seen in the previous screenshot, we are going to create a map on the left side, and on the right we will place a couple of text area components to add and get...