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

Spatial analysis with Turf


In the next example, called ch09_turf, we will extend our application's topological capabilities with Turf. Turf is a well-documented, simple, but capable, library for geospatial analysis. All the basic topological functions are in the library along with some more advanced and scarce functions. Turf uses GeoJSON not only as its exchange format but also as its internal format. This enables it to skip the overhead caused by data conversion.

Tip

You can grab the most recent version of Turf from the GitHub repository at https://github.com/Turfjs/turf/releases.

First, we open the HTML file and resolve the dependencies. We have an easy job with Turf as we only have to provide one extra JavaScript file:

<head>
    […]
    <script type="text/javascript" src="../../js/turf-2.0.0/turf.min.js"></script>
</head>

Preparing an example

Before jumping into the implementation of different spatial operations, we need to tweak our example a little bit. First, as...