trips-layer.md

Trips Layer

This layer renders animated paths that represent vehicle trips.

Installation

To install the dependencies from NPM:

npm install deck.gl
# or
npm install @deck.gl/core @deck.gl/layers @deck.gl/geo-layers

import {TripsLayer} from '@deck.gl/geo-layers';

const App = ({data, viewport}) => {

  /**
   * Data format:
   * [
   *   {
   *     waypoints: [
   *      {coordinates: [-122.3907988, 37.7664413], timestamp: 1554772579000}
   *      {coordinates: [-122.3908298,37.7667706], timestamp: 1554772579010}
   *       ...,
   *      {coordinates: [-122.4485672, 37.8040182], timestamp: 1554772580200}
   *     ]
   *   }
   * ]
   */
  const layer = new TripsLayer({
    id: 'trips-layer',
    data,
    getPath: d => d.waypoints.map(p => p.coordinates),
    // deduct start timestamp from each data point to avoid overflow
    getTimestamps: d => d.waypoints.map(p => p.timestamp - 1554772579000),
    getColor: [253, 128, 93],
    opacity: 0.8,
    widthMinPixels: 5,
    rounded: true,
    trailLength: 200,
    currentTime: 100
  });

  return (<DeckGL {...viewport} layers={[layer]} />);
};

To use pre-bundled scripts:

<script src="https://unpkg.com/deck.gl@^8.0.0/dist.min.js"></script>
<!-- or -->
<script src="https://unpkg.com/@deck.gl/core@^8.0.0/dist.min.js"></script>
<script src="https://unpkg.com/@deck.gl/layers@^8.0.0/dist.min.js"></script>
<script src="https://unpkg.com/@deck.gl/geo-layers@^8.0.0/dist.min.js"></script>

new deck.TripsLayer({});

Properties

Inherits from all Base Layer and PathLayer properties, plus the following:

Render Options

currentTime (Number, optional)

• Default: 0

The current time of the frame, i.e. the playhead of the animation.

This value should be in the same units as the timestamps from getPath.

trailLength (Number, optional)

• Default: 120

How long it takes for a path to completely fade out.

This value should be in the same units as the timestamps from getPath.

Data Accessors

getPath (Function, optional)

• Default: d => d.path

Called for each data object to retrieve paths. Returns an array of navigation points on a single path.

See PathLayer documentation for supported path formats.

getTimestamps (Function, optional)

• Default: d => d.timestamps

Returns an array of timestamps, one for each navigation point in the geometry returned by getPath, representing the time that the point is visited.

Because timestamps are stored as 32-bit floating numbers, raw unix epoch time can not be used. You may test the validity of a timestamp by calling Math.fround(t) to check if there would be any loss of precision.

Legacy API, removing in a future major release:

If getTimestamps is not supplied, each navigation point in the path is interpreted as [longitude, latitude, timestamp], and the paths will always be rendered flat against the ground.

Source

modules/geo-layers/src/trips-layer