aframe-geo-projection-component

A set of A-Frame components for creating maps in WebVR using d3-geo projections.

Components

The components in this library each handle a different responsibility, starting with loading a file of map data and progressing through to projecting that data and then rendering it. The components communicate through events. The diagram below shows an overview of the communication flow. Usually, all components are attached to the same entity.

geojson-loader component

This component loads a GeoJSON file and informs any listeners when the file has finished loading.

Component Schema

Property	Description	Default Value
src	path to a GeoJSON asset	None; required

Events

Type	Description	default object
geo-src-loaded	Fired when the GeoJSON specified in the src attribute has finished loading.	geoJson: the GeoJSON data as a JavaScript object

topojson-loader component

This component loads a TopoJSON file, converts it to GeoJSON, and informs any listeners when the file has finished loading.

Component Schema

Property	Description	Default Value
src	path to a TopoJSON asset	None; required
topologyObject	Specifies the TopoJSON topology object to convert to GeoJSON. If empty, then the first one will be used.

Events

Type	Description	default object
geo-src-loaded	Fired when the TopoJSON specified in the src attribute has finished loading.	geoJson: the GeoJSON data as a JavaScript object

geo-projection component

This component projects GeoJSON data onto a plane in VR world coordinates. It does not render anything graphically; that responsibility is handled by the renderer components.

Component Schema

Property	Description	Default Value
width	width of the plane on which to project the map	1
height	height of the plane on which to project the map	1
projection	the name of a projection from d3-geo or d3-geo-projection	geoIdentity
isCCW	Determines how shapes and holes are identified. By default solid shapes are defined clockwise (CW) and holes are defined counterclockwise (CCW). If isCCW is set to true, then those are flipped.	false

Events

Type	Description	default object
geo-data-ready	Fired when the GeoJSON data has been projected and is ready for rendering

geo-outline-renderer component

This component renders projected GeoJSON data as outlines. This is the most robust of the three renderers provided, so switch to this if you're having trouble seeing your map.

Component Schema

Property	Description	Default Value
color	If this attribute is set, then the outlines will be rendered using a THREE.LineBasicMaterial of the specified color; if not, the renderer will use the material of the attached entity. This allows for specifying custom materials.	None

geo-shape-renderer component

This component renders projected GeoJSON data as flat shapes. It uses the material attached to the entity it's associated with, so make sure to set your color there.

Component Schema

Property	Description	Default Value
isCCW	Determines how shapes and holes are identified. By default solid shapes are defined clockwise (CW) and holes are defined counterclockwise (CCW). If isCCW is set to true, then those are flipped. For most cases, the default is correct.	false

geo-extrude-renderer component

This component renders projected GeoJSON data as extruded shapes. It uses the material attached to the entity it's associated with, so make sure to set your color there.

Component Schema

Property	Description	Default Value
extrudeAmount	The amount in A-Frame units to extrude the shapes	1
isCCW	Determines how shapes and holes are identified. By default solid shapes are defined clockwise (CW) and holes are defined counterclockwise (CCW). If isCCW is set to true, then those are flipped. For most cases, the default is correct.	false

Customization

To build a custom visualization of geo data, the recommended way is to create a custom renderer component responsible for loading any additional data and performing the rendering. This component should wait for the geo-data-ready event before doing its work to avoid race conditions. The "U.S. Population by State in 2017" example shows an example of how to build a visualization using a custom component.

Installation

Browser

Install and use by directly including the browser files:

<head>
  <title>My A-Frame Scene</title>
  <script src="https://aframe.io/releases/0.8.2/aframe.min.js"></script>
  <script src="https://unpkg.com/aframe-geo-projection-component/dist/aframe-geo-projection-component.min.js"></script>
</head>

<body>
  <a-scene>
    <a-assets>
    <a-asset-item id="json-world" src="https://d2ad6b4ur7yvpq.cloudfront.net/naturalearth-3.3.0/ne_50m_land.geojson" />
    </a-assets>

      <a-entity rotation="-90 0 0"
                geojson-loader="src: #json-world;"
                geo-projection="
                  projection: geoStereographic;
                  height: 10;
                  width: 20;"
                geo-outline-renderer="color: red;"
      >
      </a-entity>
  </a-scene>
</body>

npm

Install via npm:

npm install aframe-geo-projection-component

Then require and use.

require('aframe');
require('aframe-geo-projection-component');

Development

To set up the project for development:

1. Ensure that node >= v8 is installed on your system
2. git clone the repository
3. run npm install in the root of the project directory

Once the project dependencies are installed, you can:

• run npm test to run the tests
• run npm start to load up the examples in a browser. The content is served via a budo dev server so any changes in the code will cause the web page to update automatically.
• run npm run lint to check the code for coding standard violations
• run npm run ghpages to update the github pages branch with the latest examples gallery
• run npm publish to publish the latest version of the package to npm

Credits

Created by: