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 feature selection controls


Interactions in OpenLayers 3 are related to the view or vector layers. These interactions related to vector data mostly have only this in common. Their working mechanism is highly inconsistent, it depends on the type of the given interaction. This peculiarity requires us to customize every interaction individually for our needs. In this example, called ch05_select_complex, we will create three selection tools.

Styling the controls

Firstly, we create some styles for the control buttons. We will use some nice background images to describe the controls. As we leave the text content of the buttons empty, we have to vertically center the buttons, not just the container div element. We also need to set some rules for the background images to render them properly:

.toolbar .ol-control button {
[…]
    vertical-align: middle;
    background-size: 1em;
    background-repeat: no-repeat;
    background-position: 50%;
}
[…]
.toolbar .ol-singleselect button ...