Table of Contents for
OpenLayers 3 : Beginner's Guide

Version ebook / Retour

Cover image for bash Cookbook, 2nd Edition OpenLayers 3 : Beginner's Guide by Erik Hazzard Published by Packt Publishing, 2015
  1. Cover
  2. Table of Contents
  3. OpenLayers 3 Beginner's Guide
  4. OpenLayers 3 Beginner's Guide
  5. Credits
  6. About the Authors
  7. About the Reviewers
  8. www.PacktPub.com
  9. Preface
  10. What you need for this book
  11. Who this book is for
  12. Sections
  13. Time for action – heading
  14. Conventions
  15. Reader feedback
  16. Customer support
  17. 1. Getting Started with OpenLayers
  18. Advantages of using OpenLayers
  19. What, technically, is OpenLayers?
  20. Anatomy of a web mapping application
  21. Connecting to Google, Bing Maps, and other mapping APIs
  22. Time for action – downloading OpenLayers
  23. Time for action – creating your first map
  24. Where to go for help
  25. OpenLayers issues
  26. OpenLayers source code repository
  27. Getting live news from RSS and social networks
  28. Summary
  29. 2. Key Concepts in OpenLayers
  30. Time for action – creating a map
  31. Time for action – using the JavaScript console
  32. Time for action – overlaying information
  33. OpenLayers' super classes
  34. Key-Value Observing with the Object class
  35. Time for action – using bindTo
  36. Working with collections
  37. Summary
  38. 3. Charting the Map Class
  39. Time for action – creating a map
  40. Map renderers
  41. Time for action – rendering a masterpiece
  42. Map properties
  43. Time for action – target practice
  44. Map methods
  45. Time for action – creating animated maps
  46. Events
  47. Views
  48. Time for action – linking two views
  49. Summary
  50. 4. Interacting with Raster Data Source
  51. Layers in OpenLayers 3
  52. Common operations on layers
  53. Time for action – changing layer properties
  54. Tiled versus untiled layers
  55. Types of raster sources
  56. Tiled images' layers and their sources
  57. Time for action – creating a Stamen layer
  58. Time for action – creating a Bing Maps layer
  59. Time for action – creating tiles and adding Zoomify layer
  60. Image layers and their sources
  61. Using Spherical Mercator raster data with other layers
  62. Time For action – playing with various sources and layers together
  63. Time For action – applying Zoomify sample knowledge to a single raw image
  64. Summary
  65. 5. Using Vector Layers
  66. Time for action – creating a vector layer
  67. How the vector layer works
  68. The vector layer class
  69. Vector sources
  70. Time for action – using the cluster source
  71. Time for action – creating a loader function
  72. Time for action – working with the TileVector source
  73. Time for action – a drag and drop viewer for vector files
  74. Features and geometries
  75. Time for action – geometries in action
  76. Time for action – interacting with features
  77. Summary
  78. 6. Styling Vector Layers
  79. Time for action – basic styling
  80. The style class
  81. Time for action – using the icon style
  82. Have a go hero – using the circle style
  83. Multiple styles
  84. Time for action – using multiple styles
  85. Style functions
  86. Time for action – using properties to style features
  87. Interactive styles
  88. Time for action – creating interactive styles
  89. Summary
  90. 7. Wrapping Our Heads Around Projections
  91. Time for action – using different projection codes
  92. Time for action – determining coordinates
  93. OpenLayers projection class
  94. Transforming coordinates
  95. Time for action – coordinate transforms
  96. Time for action – setting up Proj4js.org
  97. Time for action – reprojecting extent
  98. Time for action – using custom projection with WMS sources
  99. Time for action – reprojecting geometries in vector layers
  100. Summary
  101. 8. Interacting with Your Map
  102. Time for action – converting your local or national authorities data into web mapping formats
  103. Time for action – testing the use cases for ol.interaction.Select
  104. Time for action – more options with ol.interaction.Select
  105. Introducing methods to get information from your map
  106. Time for action – understanding the forEachFeatureAtPixel method
  107. Time for action – understanding the getGetFeatureInfoUrl method
  108. Adding a pop-up on your map
  109. Time for action – introducing ol.Overlay with a static example
  110. Time for action – using ol.Overlay dynamically with layers information
  111. Time for action – using ol.interaction.Draw to share new information on the Web
  112. Time for action – using ol.interaction.Modify to update drawing
  113. Understanding interactions and their architecture
  114. Time for action – configuring default interactions
  115. Discovering the other interactions
  116. Time for action – using ol.interaction.DragRotateAndZoom
  117. Time for action – making rectangle export to GeoJSON with ol.interaction.DragBox
  118. Summary
  119. 9. Taking Control of Controls
  120. Adding controls to your map
  121. Time for action – starting with the default controls
  122. Controls overview
  123. Time for action – changing the default attribution styles
  124. Time for action – finding your mouse position
  125. Time for action – configuring ZoomToExtent and manipulate controls
  126. Creating a custom control
  127. Time for action – extending ol.control.Control to make your own control
  128. Summary
  129. 10. OpenLayers Goes Mobile
  130. Using a web server
  131. Time for action – go mobile!
  132. The Geolocation class
  133. Time for action – location, location, location
  134. The DeviceOrientation class
  135. Time for action – a sense of direction
  136. Debugging mobile web applications
  137. Debugging on iOS
  138. Debugging on Android
  139. Going offline
  140. Time for action – MANIFEST destiny
  141. Going native with web applications
  142. Time for action – track me
  143. Summary
  144. 11. Creating Web Map Apps
  145. Using geospatial data from Flickr
  146. Time for action – getting Flickr data
  147. A simple application
  148. Time for Action – adding data to your map
  149. Styling the features
  150. Time for action – creating a style function
  151. Creating a thumbnail style
  152. Time for action – switching to JSON data
  153. Time for action – creating a thumbnail style
  154. Turning our example into an application
  155. Time for action – adding the select interaction
  156. Time for action – handling selection events
  157. Time for action – displaying photo information
  158. Using real time data
  159. Time for action – getting dynamic data
  160. Wrapping up the application
  161. Time for action – adding dynamic tags to your map
  162. Deploying an application
  163. Creating custom builds
  164. Creating a combined build
  165. Time for action – creating a combined build
  166. Creating a separate build
  167. Time for action – creating a separate build
  168. Summary
  169. A. Object-oriented Programming – Introduction and Concepts
  170. Going further
  171. B. More details on Closure Tools and Code Optimization Techniques
  172. Introducing Closure Library, yet another JavaScript library
  173. Time for action – first steps with Closure Library
  174. Making custom build for optimizing performance
  175. Time for action – playing with Closure Compiler
  176. Applying your knowledge to the OpenLayers case
  177. Time for action - running official examples with the internal OpenLayers toolkit
  178. Time for action - building your custom OpenLayers library
  179. Syntax and styles
  180. Time for action – using Closure Linter to fix JavaScript
  181. Summary
  182. C. Squashing Bugs with Web Debuggers
  183. Time for action – opening Chrome Developer Tools
  184. Explaining Chrome Developer debugging controls
  185. Time for action – using DOM manipulation with OpenStreetMap map images
  186. Time for action – using breakpoints to explore your code
  187. Time for action – playing with zoom button and map copyrights
  188. Using the Console panel
  189. Time for action – executing code in the Console
  190. Time for action – creating object literals
  191. Time for action – interacting with a map
  192. Improving Chrome and Developer Tools with extensions
  193. Debugging in other browsers
  194. Summary
  195. D. Pop Quiz Answers
  196. Chapter 5, Using Vector Layers
  197. Chapter 7, Wrapping Our Heads Around Projections
  198. Chapter 8, Interacting with Your Map
  199. Chapter 9, Taking Control of Controls
  200. Chapter 10, OpenLayers Goes Mobile
  201. Appendix B, More details on Closure Tools and Code Optimization Techniques
  202. Appendix C, Squashing Bugs with Web Debuggers
  203. Index

Time for action – setting up Proj4js.org

This step is similar to the way we set up the now usual template for OpenLayers 3.

  1. Download Proj4js from https://github.com/proj4js/proj4js/releases. At the time of writing, the latest version was proj4js 2.3.3; so, go ahead and download it by clicking on the proj4.js green button for 2.3.3 (or whichever the latest version is).
  2. Copy the proj4.js file into a new assets/proj4js directory at the root code directory.
  3. Add the following line in the <head> section of your code before the OpenLayers 3 library inclusion code:
    <script src="../assets/proj4js/proj4.js">
</script>
  4. You can also use the online source, http://cdnjs.cloudflare.com/ajax/libs/proj4js/2.3.3/proj4.js, for production purposes. In this case, do not forget to use a fallback to the local file if the CDN fails for any reason.
  5. Now, open up the page and start Chrome Developer Tools. Type and run the following code:
    var test_proj = proj4('EPSG:4326');
console.log(test_proj);
  6. You should see an output that looks like the following:
    Object {forward: function, inverse: function, oProj: Projection}

What just happened?

We just included the Proj4js library and tested to see if it worked. If you received an error when you attempted to call proj4('EPSG:4326'), it means that the location of the proj4.js file was wrong. Ensure that the path in the <script> tag correctly references the JavaScript file.

Proj4js custom projections

Proj4js custom projections are required, particularly when you are using data at the local level and you want to use your country official projection(s) or you depend on external data sources such as web services.

Adding custom projections

Now that the Proj4js library is included, you can do transforms with more projections, the same way we did in the previous example. Except EPSG:3857, EPSG:4326, and EPSG:4269, there are no projections defined; however, you are able to define them yourself. For example, for France, the main official EPSG code is as follows:

proj4.defs("EPSG:2154","+proj=lcc +lat_1=49 +lat_2=44 +lat_0=46.5 +lon_0=3 +x_0=700000 +y_0=6600000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs");

After this, you'd be able to use EPSG:2154 for projection transformations just like you were able to use EPSG:4326 and EPSG:3857 from the earlier examples.

A more complete list of projections (containing Proj4js definitions for nearly any EPSG code) can be found at http://epsg.io.

To get projection definitions, you can copy them from http://epsg.io or also load them from the URL. For example, adding the proj4.js script after the <script src="http://epsg.io/2154.js"></script>. The URL pattern to retrieve the definition is http://epsg.io/xxx.js where xxx is the EPSG code you want to use.

OpenLayers 3 custom projections use cases

When you are using custom projections in OpenLayers 3, you need to declare the projection, as described earlier. Use ol.proj.get to retrieve its definition and define the projection extent. For this, reuse the http://epsg.io site.

When you want to declare a custom projection, you must create an object, such as the preceding one, when you start your JavaScript code:

var projection = ol.proj.get('EPSG:2154');
projection.setExtent([-378305.81, 6093283.21, 1212610.74, 7186901.68]);

You will then be able to use the usual ol.proj.transform function with this new projection.

Sometimes, in another context for example, to provide parameters to web services it can be necessary to convert extent between projections. Let's inspect how to do this operation.