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

Building a set of drawing tools


In this example, called ch05_draw, we extend our toolbar with a method that creates a set of drawing tools. We store these tools in a new collection, as we would like to enable them, only if a vector layer is selected. As they are placed in a collection, we can easily iterate through them. Firstly, we create some new rules in our CSS file for the buttons and the disabled controls:

.toolbar .ol-control button:disabled {
    background-color: rgba(0,0,0,.2);
}
.toolbar .ol-control button:disabled:hover {
    background-color: rgba(0,0,0,.2);
}
.toolbar .ol-addpoint button {
    background-image: url(../../res/button_addpoint.png);
}
.toolbar .ol-addline button {
    background-image: url(../../res/button_addline.png);
}
.toolbar .ol-addpolygon button {
    background-image: url(../../res/button_addpolygon.png);
}

Writing the method

Before starting our method, we extend our custom interaction control with the disabling capability. It is a very simple method that...