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node-geometry-library

1.1.1 • Public • Published

Geometry Library Google Maps API V3

Node JS/ Javascript Geometry Library provides utility functions for the computation of geometric data on the surface of the Earth. Code ported from Google Maps Android API.

Features

  • Spherical contains spherical geometry utilities allowing you to compute angles, distances and areas from latitudes and longitudes.
  • Poly utility functions for computations involving polygons and polylines.
  • Encoding utilities for polyline encoding and decoding.

Installation

Issue following command:

yarn add node-geometry-library
npm i node-geometry-library

Usage

Here is an example of using GeometryLibrary:

import {SphericalUtil, PolyUtil} from "node-geometry-library"";

let response = SphericalUtil.computeHeading(
  {lat: 25.775, lng: -80.19}, // from object {lat, lng}
  {lat: 21.774, lng: -80.19} // to object {lat, lng}
);
console.log(response) // -180

let response = SphericalUtil.computeDistanceBetween(
  {lat: 25.775, lng: -80.19}, //from object {lat, lng}
  {lat: 21.774, lng: -80.19} // to object {lat, lng}
);

console.log(response) // 444891.52998049


let response =  PolyUtil.isLocationOnEdge(
  {lat: 25.774, lng: -80.19}, // point object {lat, lng}
  [
    // poligon arrays of object {lat, lng}
    {lat: 25.774, lng: -80.19},
    {lat: 18.466, lng: -66.118},
    {lat: 32.321, lng: -64.757}
  ]
);

console.log(response)  // true



let response =   PolyUtil.isLocationOnPath(
  {lat: 25.771, lng: -80.19}, // point object {lat, lng}
  [
    // poligon arrays of object {lat, lng}
    {lat: 25.774, lng: -80.19},
    {lat: 18.466, lng: -66.118},
    {lat: 32.321, lng: -64.757}
  ]
);

console.log(response) // false  

let response =  PolyUtil.containsLocation(
  {lat: 23.886, lng: -65.269}, // point object {lat, lng}
  [
    // poligon arrays of object {lat, lng}
    {lat: 25.774, lng: -80.19},
    {lat: 18.466, lng: -66.118},
    {lat: 32.321, lng: -64.757}
  ]
);

console.log(response) // false    

let response = PolyUtil.distanceToLine(
  {lat: 61.387002, lng: 23.890636}, // point object {lat, lng}
  {lat: 61.487002, lng: 23.790636}, // line startpoint object {lat, lng}
  {lat: 60.48047, lng: 22.052754} // line endpoint object {lat, lng}
);
console.log(response) // 12325.124046196 in meters

let response =  PolyUtil.encode([
  {lat: 38.5, lng: -120.2},
  {lat: 40.7, lng: -120.95},
  {lat: 43.252, lng: -126.453}
]);

console.log(response) // '_p~iF~ps|U_ulLnnqC_mqNvxq`@'


let response =  PolyUtil.decode('_p~iF~ps|U_ulLnnqC_mqNvxq`@');  

console.log(response) /**
  [ { lat: 38.5, lng: -120.2 },
    { lat: 40.7, lng: -120.95 },
    { lat: 43.252, lng: -126.45300000000002 }
  ]

  */

Available methods

PolyUtil class

SphericalUtil class


containsLocation( point, polygon, geodesic = false ) - To find whether a given point falls within a polygon

  • point - {'lat': 38.5, 'lng': -120.2}
  • polygon - [ {'lat': 38.5, 'lng': -120.2}, {'lat': 40.7, 'lng': -120.95 }, {'lat': 43.252, 'lng': -126.453} ]
  • geodesic - boolean

Returns boolean

 
const response =  PolyUtil.containsLocation(
              {'lat': 23.886, 'lng': -65.269}, // point object of {lat, lng}
             [ // poligon arrays of object {lat, lng}
                {'lat': 25.774, 'lng': -80.190},
                {'lat': 18.466, 'lng': -66.118},
                {'lat': 32.321, 'lng': -64.757}
             ]);  
 
console.log(response) // false
 

isLocationOnEdge( point, polygon, tolerance = PolyUtil.DEFAULT_TOLERANCE, geodesic = true ) - To determine whether a point falls on or near a polyline, or on or near the edge of a polygon, within a specified tolerance in meters.

  • point - {'lat': 25.774, 'lng': -80.190}
  • polygon - [{'lat': 38.5, 'lng': -120.2}, {'lat': 40.7, 'lng': -120.95}, {'lat': 43.252, 'lng': -126.453}]
  • tolerance - tolerance value in degrees
  • geodesic - boolean

Returns boolean

 
const response =  PolyUtil.isLocationOnEdge(
              {'lat': 25.774, 'lng': -80.190}, // point object {lat, lng}
              [ // poligon arrays of object {lat, lng}
                {'lat': 25.774, 'lng': -80.190},
                {'lat': 18.466, 'lng': -66.118},
                {'lat': 32.321, 'lng': -64.757}
              ])  ;
 
console.log(response) // true
 

isLocationOnPath( point, polygon, tolerance = PolyUtil.DEFAULT_TOLERANCE, geodesic = true ) - To determine whether a point falls on or near a polyline, within a specified tolerance in meters

  • point - {'lat': 25.774, 'lng': -80.190}
  • polygon - [{'lat': 38.5, 'lng': -120.2}, {'lat': 40.7, 'lng': -120.95}, {'lat': 43.252, 'lng': -126.453}]
  • tolerance - tolerance value in degrees
  • geodesic - boolean

Returns boolean

 
response = PolyUtil.isLocationOnPath(
              {'lat': 25.774, 'lng': -80.190}, // point object if {lat, lng}
              [ // poligon arrays of object {lat, lng}
                {'lat': 25.774, 'lng': -80.190},
                {'lat': 18.466, 'lng': -66.118},
                {'lat': 32.321, 'lng': -64.757}
              ])  ;
 
console.log(response) // true
 

distanceToLine( p, start, end ) - To calculate distance from a point to line start->end on sphere.

  • p - {'lat': 61.387002, 'lng': 23.890636}
  • start - {'lat': 61.487002, 'lng': 23.790636}
  • end - {'lat': 60.48047, 'lng': 22.052754}

Returns distance from a point to line

 
const response = PolyUtil.distanceToLine(
              {'lat': 61.387002, 'lng': 23.890636}, // point object {lat, lng}
              {'lat': 61.487002, 'lng': 23.790636}, // line start point object {lat, lng}
              {'lat': 60.48047, 'lng': 22.052754}// line endpoint object {lat, lng}
             );  
 
console.log(response) // 12325.124046196 in meters
 

decode( encodedPath ) - Decodes an encoded path string into a sequence of LatLngs.

  • encodedPath - string '_p~iF~ps|U_ulLnnqC_mqNvxq`@'

Returns array

 
const response = PolyUtil.decode('_p~iF~ps|U_ulLnnqC_mqNvxq`@');  
 
console.log(response);
/*
  [ { lat: 38.5, lng: -120.2 },
    { lat: 40.7, lng: -120.95 },
    { lat: 43.252, lng: -126.45300000000002 }
  ]
 
*/
 

encode( path ) - Encodes a sequence of LatLngs into an encoded path string.

  • path - [ {'lat': 38.5, 'lng': -120.2}, {'lat': 40.7, 'lng': -120.95}, {'lat': 43.252, 'lng': -126.453} ]

Returns string

 
response =  PolyUtil.encode(
              [
                {'lat': 38.5, 'lng': -120.2},
                {'lat': 40.7, 'lng': -120.95},
                {'lat': 43.252, 'lng': -126.453}
              ]);
 
console.log(response); // '_p~iF~ps|U_ulLnnqC_mqNvxq`@'
 

computeHeading( from, to ) - Returns the heading from one LatLng to another LatLng.

  • from - {'lat': 38.5, 'lng': -120.2}
  • to - {'lat': 40.7, 'lng': -120.95}

Returns int

 
response =  SphericalUtil.computeHeading(
              {'lat': 25.775, 'lng': -80.190},
              {'lat': 21.774, 'lng': -80.190}));
 
console.log(response); // -180
 

computeOffset( from, distance, heading ) - Returns the LatLng resulting from moving a distance from an origin in the specified heading.

  • from - {'lat': 38.5, 'lng': -120.2}
  • distance - number, the distance to travel
  • heading - number, the heading in degrees clockwise from north

Returns array

 
response =  SphericalUtil.computeOffset({'lat': 25.775, 'lng': -80.190}, 152, 120);
 
console.log(response);
 
/*
  {
    'lat': 25.774316510639,
    'lng': -80.188685385944
  }
*/
 

computeOffsetOrigin( from, distance, heading ) - Returns the location of origin when provided with a LatLng destination, meters travelled and original heading. Headings are expressed in degrees clockwise from North.

  • from - {'lat': 38.5, 'lng': -120.2}
  • distance - number, the distance to travel
  • heading - number, the heading in degrees clockwise from north

Returns array

 
response =  SphericalUtil.computeOffsetOrigin({'lat': 25.775, 'lng': -80.190}, 152, 120);
 
console.log(response);
/*
  {
    'lat': 14.33435503928,
    'lng': -263248.24242931
  }
*/
 

interpolate( from, to, fraction ) - Returns the LatLng which lies the given fraction of the way between the origin LatLng and the destination LatLng.

  • from - {'lat': 38.5, 'lng': -120.2}
  • to - {'lat': 38.5, 'lng': -120.2}
  • fraction - number, a fraction of the distance to travel

Returns array

 
response =  SphericalUtil.interpolate({'lat': 25.775, 'lng': -80.190}, {'lat':26.215, 'lng': -81.218}, 2);
 
console.log(response);
/*
    {
      'lat': 26.647635362403,
      'lng': -82.253737943391
    }
*/
 

computeDistanceBetween( from, to ) - Returns the distance, in meters, between two LatLngs. You can optionally specify a custom radius. The radius defaults to the radius of the Earth.

  • from - {'lat': 38.5, 'lng': -120.2}
  • to - {'lat': 38.5, 'lng': -120.2}

Returns float

 
response =  SphericalUtil.computeDistanceBetween({'lat': 25.775, 'lng': -80.190}, {'lat': 26.215, 'lng': -81.218});
 
console.log(response); //float 113797.92421349
 

computeLength( path ) - Returns the length of the given path, in meters, on Earth.

  • path - [ {'lat': 38.5, 'lng': -120.2}, {'lat': 40.7, 'lng': -120.95}, {'lat': 43.252, 'lng': -126.453} ]

Returns float

 
const response =  SphericalUtil.computeLength([
                {'lat': 38.5, 'lng': -120.2},
                {'lat': 40.7, 'lng': -120.95},
                {'lat': 43.252, 'lng': -126.453}
              ]);
 
console.log(response); //float 788906.98459431
 

computeArea( path ) - Returns the area of a closed path.

  • path - [ {'lat': 38.5, 'lng': -120.2}, {'lat': 40.7, 'lng': -120.95}, {'lat': 43.252, 'lng': -126.453} ]

Returns float

 
response =  SphericalUtil.computeArea([
                {'lat': 38.5, 'lng': -120.2},
                {'lat': 40.7, 'lng': -120.95},
                {'lat': 43.252, 'lng': -126.453}
              ]);
 
console.log(response); //float 44766785529.143
 

computeSignedArea( path ) - Returns the signed area of a closed path.

  • path - [ {'lat': 38.5, 'lng': -120.2}, {'lat': 40.7, 'lng': -120.95}, {'lat': 43.252, 'lng': -126.453} ]

Returns float

 
response =  SphericalUtil.computeSignedArea([
                {'lat': 38.5, 'lng': -120.2},
                {'lat': 40.7, 'lng': -120.95},
                {'lat': 43.252, 'lng': -126.453}
              ]);
 
console.log(response); //float 44766785529.143
 

Credits

alexpechkarev

Support

Please open an issue on GitHub

License

Geometry Library Google Maps API V3 is released under the MIT License. See the bundled LICENSE file for details.

Install

npm i node-geometry-library

DownloadsWeekly Downloads

246

Version

1.1.1

License

MIT

Unpacked Size

80.7 kB

Total Files

16

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