mapbox-gl-shadow-simulator

Shadow simulator for Mapbox GL JS and MapLibre GL JS. Visualize sunlight and shadow on a map for any date and time of year.

Mapbox GL JS Demo | Maplibre GL Demo

Download

unpkg CDN

Installation

In a browser:

<script src="https://unpkg.com/mapbox-gl-shadow-simulator/dist/mapbox-gl-shadow-simulator.umd.min.js"></script>

Using npm:

npm i mapbox-gl-shadow-simulator --save

Usage

In a browser:

<script src='https://api.mapbox.com/mapbox-gl-js/v2.8.2/mapbox-gl.js'></script>
<link href='https://api.mapbox.com/mapbox-gl-js/v2.8.2/mapbox-gl.css' rel='stylesheet' />
<script src="https://unpkg.com/mapbox-gl-shadow-simulator/dist/mapbox-gl-shadow-simulator.umd.min.js"></script>
<script>
  const map = new mapboxgl.Map({
    // mapboxgl Map options
    // ... 
  });

  map.on('load', () => {
    const shadeMap = new ShadeMap({
      date: new Date(),    // display shadows for current date
      color: '#01112f',    // shade color
      opacity: 0.7,        // opacity of shade color
      apiKey: "XXXXXX",    // obtain from https://shademap.app/about/
      terrainSource: {
        tileSize: 256,       // DEM tile size
        maxZoom: 15,         // Maximum zoom of DEM tile set
        getSourceUrl: ({ x, y, z }) => {
          // return DEM tile url for given x,y,z coordinates
          return `https://s3.amazonaws.com/elevation-tiles-prod/terrarium/${z}/${x}/${y}.png`
        },
        getElevation: ({ r, g, b, a }) => {
          // return elevation in meters for a given DEM tile pixel
          return (r * 256 + g + b / 256) - 32768
        }
      },
      debug: (msg) => { console.log(new Date().toISOString(), msg) },
    }).addTo(map);

    // advance shade by 1 hour
    shadeMap.setDate(new Date(Date.now() + 1000 * 60 * 60)); 

    // sometime later...
    // ...remove layer
    shadeMap.remove();
  });
</script>

Using Node.js:

import mapboxgl from 'mapbox-gl/dist/mapbox-gl';
import ShadeMap from 'mapbox-gl-shadow-simulator';

const map = new mapboxgl.Map({
  // mapboxgl Map options
  // ... 
});

map.on('load', () => {
  const shadeMap = new ShadeMap({
    date: new Date(),    // display shadows for current date
    color: '#01112f',    // shade color
    opacity: 0.7,        // opacity of shade color
    apiKey: "XXXXXX",    // obtain from https://shademap.app/about/
    terrainSource: {
      tileSize: 256,       // DEM tile size
      maxZoom: 15,         // Maximum zoom of DEM tile set
      getSourceUrl: ({ x, y, z }) => {
        // return DEM tile url for given x,y,z coordinates
        return `https://s3.amazonaws.com/elevation-tiles-prod/terrarium/${z}/${x}/${y}.png`
      },
      getElevation: ({ r, g, b, a }) => {
        // return elevation in meters for a given DEM tile pixel
        return (r * 256 + g + b / 256) - 32768
      }
    },
    debug: (msg) => { console.log(new Date().toISOString(), msg) },
  }).addTo(map);

  // advance shade by 1 hour
  shadeMap.setDate(new Date(Date.now() + 1000 * 60 * 60)); 

  // sometime later
  // ...remove layer
  shadeMap.remove();
});

Constructor options

Property name | Type | Default value | Comment :--- | :--- | :--- | :--- apiKey | String | '' | See https://shademap.app/about/ date | Date | new Date() | Sun's position in the sky is based on this date color | String | #000 | 3 or 6 digit hexadecimal number opacity | Number | 0.3 sunExposure | Object | See sunExposure | Display sun exposure for provided date range terrainSource | Object | See terrainSource | Specify DEM or DSM tiles containing terrain elevation data getFeatures | Function | See getFeatures | Returns GeoJSON of objects, such as buildings, to display on the map

terrainSource

An object describing a DEM tile set to use for terrain shadows

Property name | Type | Default value | Comment :--- | :--- | :--- | :--- maxZoom | Number | 15 | Max zoom for custom DEM tile source tileSize | Number | 256 | Tile size for custom DEM tile source sourceUrl | Function | Returns tile encoding 0m elevation for all locations | Returns url of DEM tile for given (x, y, z) coordinate getElevation | Function | return (r * 256 + g + b / 256) - 32768 | Returns elevation in meters for each (r,g,b,a) pixel of DEM tile

sunExposure

An object describing sun exposure settings Property name | Type | Default value | Comment :--- | :--- | :--- | :--- enabled | Boolean | false | Should sun exposure be displayed startDate | Date | new Date() | Start date of sun exposure time interval endDate | Date | new Date() | End date of sun exposure time interval iterations | number | 32 | Number of discrete chunks to calculate shadows for between startDate and endDate. A larger number will provide more detail but take longer to compute.

Open Data on AWS for terrainSource

A global dataset providing bare-earth terrain heights, tiled for easy usage and provided on S3 - More info

{
  tileSize: 256,
  maxZoom: 15,
  getSourceUrl: ({x, y, z}) => {
    return `https://s3.amazonaws.com/elevation-tiles-prod/terrarium/${z}/${x}/${y}.png`;
  },
  getElevation: ({r, g, b, a}) => {
    return (r * 256 + g + b / 256) - 32768;
  }
}

Mapbox Terrain DEM V1 for terrainSource

Mapbox Terrain-DEM v1 is a Mapbox-provided raster tileset is a global elevation layer. This tileset contains raw height values in meters in the Red, Green, and Blue channels of PNG tiles that can be decoded to raw heights in meters - More info

{
  tileSize: 514,
  maxZoom: 14,
  getSourceUrl: ({x, y, z}) => {
    const subdomain = ['a', 'b', 'c', 'd'][(x + y) % 4];
    return `https://${subdomain}.tiles.mapbox.com/raster/v1/mapbox.mapbox-terrain-dem-v1/${z}/${x}/${y}.webp?sku=101wuwGrczDtH&access_token=${MAPBOX_API_KEY}`;
  },
  getElevation: ({r, g, b, a}) => {
    return -10000 + ((r * 256 * 256 + g * 256 + b) * .1);
  }
}

Maptiler Terrain RGB v2

More info

{
  tileSize: 514,
  maxZoom: 12,
  getSourceUrl: ({x, y, z}) => {
    return `https://api.maptiler.com/tiles/terrain-rgb-v2/${z}/${x}/${y}.webp?key=${MAPTILER_KEY}`;
  },
  getElevation: ({r, g, b, a}) => {
    return -10000 + ((r * 256 * 256 + g * 256 + b) * .1);
  }
}

getFeatures

Returns a GeoJSON collection of features whose shadows will be displayed on the map. Currently only supports Polygon and MultiPolygon.

Extracting buildings from Mapbox vector tiles

getFeatures: () => {
  // wait for map.loaded() to ensure all vector tile data downloaded
  const buildingData = map.querySourceFeatures('composite', { sourceLayer: 'building' }).filter((feature) => {
    return feature.properties && feature.properties.underground !== "true" && (feature.properties.height || feature.properties.render_height)
  });
  return buildingData;
},

Available functions

setDate(date: Date) - update shade layer to reflect new date

setColor(color: String) - change shade color

setOpacity(opacity: Number) - change shade opacity

setSunExposure(enabled: Boolean, options: SunExposureOptions) - toggle between shadows and sun exposure mode

getHoursOfSun(x: Number, y: Number) - if sun exposure mode enabled, returns the hours of sunlight for a given pixel on the map

remove() - remove the layer from the map