Book Image

Mastering OpenLayers 3

By : Gábor Farkas
Book Image

Mastering OpenLayers 3

By: Gábor Farkas

Overview of this book

OpenLayers 3 allows you to create stunning web mapping and WebGIS applications. It uses modern, cutting edge browser technologies. It is written with Closure Library, enabling you to build browser-independent applications without painful debugging ceremonies, which even have some limited fallback options for older browsers. With this guide, you will be introduced to the world of advanced web mapping and WebGIS. First, you will be introduced to the advanced features and functionalities available in OpenLayers 3. Next, you will be taken through the key points of creating custom applications with OpenLayers 3. You will then learn how to create the web mapping application of yours (or your company's) dream with this open source, expense-free, yet very powerful library. We’ll also show you how to make amazing looking thematic maps and create great effects with canvas manipulation. By the end of this book, you will have a strong command of web mapping and will be well on your way to creating amazing applications using OpenLayers 3.
Table of Contents (17 chapters)
Mastering OpenLayers 3
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Customizing the appearance with JavaScript


Apart from direct styling with CSS, OpenLayers 3 offers some methods to specify the appearance of our maps. These methods can be used to make such changes in the behavior of the controls, which would otherwise be quite hard to achieve, if not impossible. In the next example, we will look at some of the JavaScript-based customizing options.

If you open up the code attachment, you can see some files named ch02_controls. In these files, you can examine the changes we made to the previous example. The main changes, like the title suggests, will be in the JavaScript part of the example.

Changing the overview map and the scale bar

In this example, we will group the controls based on their position on the map. In the bottom-left corner, we already lifted the overview map above the scale bar. Now, it is time to change some of their inner properties:

var map = new ol.Map({
    […]
    controls: [
        […]
        new ol.control.ScaleLine({
            units...