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 talks about vector layers. In addition to raster, vector information is the other important type of information we can work with in a GIS system.

The chapter tries to summarize the most common and important recipes you may need to work with in OpenLayers.

In GIS, a real-world phenomenon is represented by the concept of a feature. It can be a place—like a city or a village—it can be a road or a railway, it can be a region, a lake, the border of a country, or something similar.

Every feature has a set of attributes: population, length, and so on. It is represented visually by a geometrical symbol: point, line, polygon, and so on, using some visual style: color, radius, width, and so on.

As you can see, there are many concepts to take into account when working with vector information. Fortunately, OpenLayers provides us classes to work with them. We will learn more about these in this chapter.

The base class for vector layers is OpenLayers.Layer.Vector class, which defines...