three-geo

by w3reality

w3reality / three-geo

Geographic visualization library using three.js

285 Stars 53 Forks Last release: 4 months ago (v1.4.2) MIT License 219 Commits 3 Releases

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three-geo

three-geo is a three.js based geographic visualization library. Using three-geo, we can easily build satellite-textured 3D terrain models in near real-time by simply specifying GPS coordinates anywhere on the globe. The geometry of the terrain is based on the RGB-encoded DEM (Digital Elevation Model) provided by the Mapbox Maps API.

The terrain is represented by standard THREE.Mesh objects. This makes it easy for us to access underlying geometry/texture array and perform original GIS (Geographic Information System) experiments in JavaScript. (See Usage for how to programatically obtain those mesh objects).

Credits: this library has been made possible thanks to

Demo

1) examples/geo-viewer (live | source code)

This demo app includes features such as

  • on-demand 3D terrain building (by a mouse click on the Leaflet map),
  • real-time camera projection onto Leaflet (with oritentaion and HFoV indication),
  • terrain interaction with a VR-like laser beam,
  • measuring Euclidean distances between terrain points,
  • auto camera orbiting around the custom z-axis.

Live:

image

image

image

2) examples/heightmaps (live | source code)

This demo illustrates the relationship between a reconstructed 3D terrain and its underlying satellite/DEM tiles.

image

3) examples/flat (live | source code)

How to get a flattened view of the terrain by post-editing the underlying geometry.

4) examples/projection (live | source code)

How to register a new 3D object on top of the terrain based on its geographic location

[latitude, longitude, elevation]
.

Setup

Installation

$ npm i three-geo

Loading

Script tag: use

ThreeGeo
after

ES6:

import ThreeGeo from 'dist/three-geo.esm.js';

Usage

Here is an example of how to build a geographic terrain located at GPS coordinates (46.5763, 7.9904) in a 5 km radius circle. The terrain's satellite zoom resolution is set to 12. (The highest zoom value supported is 17.)

For standalone tests, use examples/simple-viewer (source code).

const tgeo = new ThreeGeo({
    tokenMapbox: '********', // 

image

Who is using
three-geo
?

API

In this section, we list

three-geo
's public API methods, where
origin
,
radius
, and
zoom
are parameters common to them:
  • origin
    Array<number> Center of the terrain represented as GPS coordinates
    [latitude, longitude]
    .
  • radius
    number Radius of the circle that fits the terrain.
  • zoom
    number (integer) Satellite zoom resolution of the tiles in the terrain. Select from {11, 12, 13, 14, 15, 16, 17}, where 17 is the highest value supported. For a fixed radius, higher zoom resolution results in more tileset API calls.

ThreeGeo
  • constructor(opts={})

Create a ThreeGeo instance with parameters.

  • opts.tokenMapbox
    =\"\" string Mapbox API token. This must be provided.
  • opts.unitsSide
    =1.0 number The side length of the square that fits the terrain in WebGL space.
    • async getTerrainRgb(origin, radius, zoom)
      [ Added in v1.4 ]

Return a THREE.Group object that represents a 3D surface of the terrain.

The group object contains an Array<THREE.Mesh> as

.children
. Each mesh corresponds to a partial geometry of the terrain textured with satellite images.
  • async getTerrainVector(origin, radius, zoom)
    [ Added in v1.4 ]

Return a THREE.Group object that represents a 3D contour map of the terrain.

The group object contains an Array<THREE.Object3D> as

.children
. Each child object is either an extruded THREE.Mesh with
.name
attribute prefixed by
dem-vec-shade--
, or a THREE.Line with
.name
prefixed by
dem-vec-line--
(
 is the height of each contour in meters).

  • getProjection(origin, radius, unitsSide=1.0)
    [ Example ]

Return an object

{ proj, projInv, bbox, unitsPerMeter }
that includes transformation-related functions and parameters, where
  • proj(latlng)
    is a function that maps geo coordinates
    latlng
    (an array
    [lat, lng]
    ) to WebGL coordinates
    [x, y]
    .
  • projInv(x, y)
    is a function that maps WebGL coordinates
    [x, y]
    to geo coordinates
    [lat, lng]
    .
  • bbox
    is an array
    [w, s, e, n]
    that represents the computed bounding box of the terrain, where
    w
    (West) and
    e
    (East) are longitudinal limits; and
    s
    (South) and
    n
    (North) are latitudinal limits.
  • unitsPerMeter
    is the length in WebGL-space per meter.

Legacy callback based API
  • getTerrain(origin, radius, zoom, callbacks={})

    • callbacks.onRgbDem function (meshes) {} Implement this to request the geometry of the terrain. Called when the entire terrain's geometry is obtained.

      • meshes Array<three.mesh> All the meshes belonging to the terrain.
    • callbacks.onSatelliteMat function (mesh) {} Implement this to request the satellite textures of the terrain. Called when the satellite texture of each mesh belonging to the terrain is obtained.

      • mesh THREE.Mesh One of the meshes that's part of the terrain.
    • callbacks.onVectorDem function (objs) {} Implement this to request the contour map of the terrain. Called when the contour map of the terrain is obtained.

      • objs Array<three.object3d> Extruded meshes (THREE.Mesh objects with .name attribute prefixed by dem-vec-shade-<ele>-) and lines (THREE.Line objects with .name attribute prefixed by dem-vec-line-<ele>-), where <ele> is the height of each contour in meters.

</three.object3d></three.mesh>

Build

$ npm i
$ npm run build

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