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

Changing the map's projection


In the next example, called ch06_projection, we close our basic WebGIS client with a final control, which is able to change the map's projection dynamically. First, as we will need the PROJ4JS library for this example, we include it in the HTML file:

<script type="text/javascript" src="../../js/proj4js-2.3.10/proj4.js"></script>

Next, we style the control with CSS:

.notification-bar #projection {
    text-align: center;
}
.notification-bar #projection select {
    background: none;
    border: none;
    outline: 0;
}

The scheme is the same as the one in the previous example. We will strip the natural look of the select element, which will contain the possible projection options. Next, we start building the control by creating two options for the two default projections:

ol.control.Projection = function (opt_options) {
    var options = opt_options || {};
    var _this = this;
    var projSwitcher = document.createElement('select');
    var webMercator...