whuber algorithm

by hoolymama

HTML

<script src="https://maps.googleapis.com/maps/api/js?sensor=false&amp;libraries=geometry,places&amp;ext=.js"></script>
<div id="map" style="border: 2px solid #3872ac;"></div>

CSS

html,
body,
#map {
  height: 500px;
  width: 500px;
  margin: 0px;
  padding: 0px
}

JavaScript

const EARTH_RADIUS = 6371000
const DEG_TO_RAD = Math.PI / 180.0
const ONE_DEGREE = EARTH_RADIUS * DEG_TO_RAD
const THREE_PI = Math.PI * 3
const TWO_PI = Math.PI * 2

function isFloat(n) {
  return !isNaN(parseFloat(n)) && isFinite(n);
}

function recursiveConvert(input, callback) {
  if (input instanceof Array) {
    return input.map((el) => recursiveConvert(el, callback))
  }
  if (input instanceof Object) {
    input = JSON.parse(JSON.stringify(input))
    for (let key in input) {
      if (input.hasOwnProperty(key)) {
        input[key] = recursiveConvert(input[key], callback)
      }
    }
    return input
  }
  if (isFloat(input)) {
    return callback(input)
  }
}

function toRadians(input) {
  return recursiveConvert(input, (val) => val * DEG_TO_RAD)
}

function toDegrees(input) {
  return recursiveConvert(input, (val) => val / DEG_TO_RAD)
}

lengthOf = function(x, y) {
  return Math.sqrt(x * x + y * y)
}


function whuberPointAtDistance(coords, distance) {
  var r = distance / 111300,
    y0 = coords.latitude,
    x0 = coords.longitude,
    u = 1,
    v = Math.random(),
    w = r * Math.sqrt(u),
    t = 2 * Math.PI * v,
    x = w * Math.cos(t),
    y1 = w * Math.sin(t),
    x1 = x / Math.cos(y0)

  newY = y0 + y1
  newX = x0 + x1
  return {
    latitude: newY,
    longitude: newX
  }
}


function distanceBetween(start, end) {
  const startPoint = toRadians(start)
  const endPoint = toRadians(end)
  const delta = {
    latitude: endPoint.latitude - startPoint.latitude,
    longitude: endPoint.longitude - startPoint.longitude
  }

  const sinDelta = {
    latitude: Math.sin(delta.latitude / 2),
    longitude: Math.sin(delta.longitude / 2)
  }

  const A = sinDelta.latitude * sinDelta.latitude +
    sinDelta.longitude * sinDelta.longitude * Math.cos(startPoint.latitude) * Math.cos(endPoint.latitude)

  return EARTH_RADIUS * 2 * Math.atan2(Math.sqrt(A), Math.sqrt(1 - A))

}


var initLoc = {
  "latitude": 67.498454,
  "longitude": 21.040181
}


var locations...