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

Adding vector layers with the File API


The HTML5 File API makes it possible for us to load nearly any kind of file from our hard drive to a browser and process these files with JavaScript. It has capabilities way beyond our use case (it can even handle binary files); thus, it is advisable for every frontend developer to look into it in further detail. The files for this example are named ch03_fileapi.

First, we create a new form as usual. You can grab it from the HTML file.

Creating the interface

The basic interface to access our new functionality is the same, as shown in the previous examples. First, we extend our layer constructor, adding a new button to the layer tree:

var layerTree = function (options) {
[…]
        controlDiv.appendChild(this.createButton('addvector', 'Add Vector Layer', 'addlayer'));
[…]
};

Next, we create a new rule for its button class in our CSS file:

.layertree-buttons .addvector {
    background-image: url(../../res/button_vector.png);
}

We also add a new event listener...