Add spherical geometry functions

This commit is contained in:
Tom Payne
2013-02-15 17:55:29 +01:00
parent 012cb501df
commit 544f399e04
2 changed files with 740 additions and 0 deletions

189
src/ol/sphere.js Normal file
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/**
* @license
* Latitude/longitude spherical geodesy formulae taken from
* http://www.movable-type.co.uk/scripts/latlong.html
* Licenced under CC-BY-3.0.
*/
// FIXME add intersection of two paths given start points and bearings
// FIXME add rhumb lines
goog.provide('ol.Sphere');
goog.require('goog.math');
goog.require('ol.Coordinate');
/**
* @constructor
* @param {number} radius Radius.
*/
ol.Sphere = function(radius) {
/**
* @type {number}
*/
this.radius = radius;
};
/**
* Returns the distance from c1 to c2 using the spherical law of cosines.
*
* @param {ol.Coordinate} c1 Coordinate 1.
* @param {ol.Coordinate} c2 Coordinate 2.
* @return {number} Spherical law of cosines distance.
*/
ol.Sphere.prototype.cosineDistance = function(c1, c2) {
var lat1 = goog.math.toRadians(c1.y);
var lat2 = goog.math.toRadians(c2.y);
var deltaLon = goog.math.toRadians(c2.x - c1.x);
return this.radius * Math.acos(
Math.sin(lat1) * Math.sin(lat2) +
Math.cos(lat1) * Math.cos(lat2) * Math.cos(deltaLon));
};
/**
* Returns the distance of c3 from the great circle path defined by c1 and c2.
*
* @param {ol.Coordinate} c1 Coordinate 1.
* @param {ol.Coordinate} c2 Coordinate 2.
* @param {ol.Coordinate} c3 Coordinate 3.
* @return {number} Cross-track distance.
*/
ol.Sphere.prototype.crossTrackDistance = function(c1, c2, c3) {
var d12 = this.cosineDistance(c1, c2);
var d13 = this.cosineDistance(c1, c2);
var theta12 = goog.math.toRadians(this.initialBearing(c1, c2));
var theta13 = goog.math.toRadians(this.initialBearing(c1, c3));
return this.radius *
Math.asin(Math.sin(d13 / this.radius) * Math.sin(theta13 - theta12));
};
/**
* Returns the distance from c1 to c2 using Pythagoras's theorem on an
* equirectangular projection.
*
* @param {ol.Coordinate} c1 Coordinate 1.
* @param {ol.Coordinate} c2 Coordinate 2.
* @return {number} Equirectangular distance.
*/
ol.Sphere.prototype.equirectangularDistance = function(c1, c2) {
var lat1 = goog.math.toRadians(c1.y);
var lat2 = goog.math.toRadians(c2.y);
var deltaLon = goog.math.toRadians(c2.x - c1.x);
var x = deltaLon * Math.cos((lat1 + lat2) / 2);
var y = lat2 - lat1;
return this.radius * Math.sqrt(x * x + y * y);
};
/**
* Returns the final bearing from c1 to c2.
*
* @param {ol.Coordinate} c1 Coordinate 1.
* @param {ol.Coordinate} c2 Coordinate 2.
* @return {number} Initial bearing.
*/
ol.Sphere.prototype.finalBearing = function(c1, c2) {
return (this.initialBearing(c2, c1) + 180) % 360;
};
/**
* Returns the distance from c1 to c2 using the haversine formula.
*
* @param {ol.Coordinate} c1 Coordinate 1.
* @param {ol.Coordinate} c2 Coordinate 2.
* @return {number} Haversine distance.
*/
ol.Sphere.prototype.haversineDistance = function(c1, c2) {
var lat1 = goog.math.toRadians(c1.y);
var lat2 = goog.math.toRadians(c2.y);
var deltaLatBy2 = (lat2 - lat1) / 2;
var deltaLonBy2 = goog.math.toRadians(c2.x - c1.x) / 2;
var a = Math.sin(deltaLatBy2) * Math.sin(deltaLatBy2) +
Math.sin(deltaLonBy2) * Math.sin(deltaLonBy2) *
Math.cos(lat1) * Math.cos(lat2);
return 2 * this.radius * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
};
/**
* Returns the initial bearing from c1 to c2.
*
* @param {ol.Coordinate} c1 Coordinate 1.
* @param {ol.Coordinate} c2 Coordinate 2.
* @return {number} Initial bearing.
*/
ol.Sphere.prototype.initialBearing = function(c1, c2) {
var lat1 = goog.math.toRadians(c1.y);
var lat2 = goog.math.toRadians(c2.y);
var deltaLon = goog.math.toRadians(c2.x - c1.x);
var y = Math.sin(deltaLon) * Math.cos(lat2);
var x = Math.cos(lat1) * Math.sin(lat2) -
Math.sin(lat1) * Math.cos(lat2) * Math.cos(deltaLon);
return goog.math.toDegrees(Math.atan2(y, x));
};
/**
* Returns the maximum latitude of the great circle defined by bearing and
* latitude.
*
* @param {number} bearing Bearing.
* @param {number} latitude Latitude.
* @return {number} Maximum latitude.
*/
ol.Sphere.prototype.maximumLatitude = function(bearing, latitude) {
return Math.cos(Math.abs(Math.sin(goog.math.toRadians(bearing)) *
Math.cos(goog.math.toRadians(latitude))));
};
/**
* Returns the midpoint between c1 and c2.
*
* @param {ol.Coordinate} c1 Coordinate 1.
* @param {ol.Coordinate} c2 Coordinate 2.
* @return {ol.Coordinate} Midpoint.
*/
ol.Sphere.prototype.midpoint = function(c1, c2) {
var lat1 = goog.math.toRadians(c1.y);
var lat2 = goog.math.toRadians(c2.y);
var lon1 = goog.math.toRadians(c1.x);
var deltaLon = goog.math.toRadians(c2.x - c1.x);
var Bx = Math.cos(lat2) * Math.cos(deltaLon);
var By = Math.cos(lat2) * Math.sin(deltaLon);
var cosLat1PlusBx = Math.cos(lat1) + Bx;
var lat = Math.atan2(Math.sin(lat1) + Math.sin(lat2),
Math.sqrt(cosLat1PlusBx * cosLat1PlusBx + By * By));
var lon = lon1 + Math.atan2(By, cosLat1PlusBx);
return new ol.Coordinate(goog.math.toDegrees(lon), goog.math.toDegrees(lat));
};
/**
* Returns the coordinate at the given distance and bearing from c.
*
* @param {ol.Coordinate} c1 Coordinate.
* @param {number} distance Distance.
* @param {number} bearing Bearing.
* @return {ol.Coordinate} Coordinate.
*/
ol.Sphere.prototype.offset = function(c1, distance, bearing) {
var lat1 = goog.math.toRadians(c1.y);
var lon1 = goog.math.toRadians(c1.x);
var dByR = distance / this.radius;
var lat = Math.asin(
Math.sin(lat1) * Math.cos(dByR) +
Math.cos(lat1) * Math.sin(dByR) * Math.cos(bearing));
var lon = lon1 + Math.atan2(
Math.sin(bearing) * Math.sin(dByR) * Math.cos(lat1),
Math.cos(dByR) - Math.sin(lat1) * Math.sin(lat));
return new ol.Coordinate(goog.math.toDegrees(lon), goog.math.toDegrees(lat));
};

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test/spec/ol/sphere.test.js Normal file
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// See http://www.movable-type.co.uk/scripts/latlong.html
// FIXME add tests for crossTrackDistance
// FIXME add tests for maximumLatitude
// FIXME add tests for offset
goog.provide('ol.test.Sphere');
describe('ol.Sphere', function() {
var sphere = new ol.Sphere(6371);
var expected = [
{
c1: new ol.Coordinate(0, 0),
c2: new ol.Coordinate(0, 0),
cosineDistance: 0,
equirectangularDistance: 0,
finalBearing: 180,
haversineDistance: 0,
initialBearing: 0,
midpoint: new ol.Coordinate(0, 0)
},
{
c1: new ol.Coordinate(0, 0),
c2: new ol.Coordinate(45, 45),
cosineDistance: 6671.695598673524,
equirectangularDistance: 6812.398372654371,
finalBearing: 54.735610317245346,
haversineDistance: 6671.695598673525,
initialBearing: 35.264389682754654,
midpoint: new ol.Coordinate(18.434948822922006, 24.0948425521107)
},
{
c1: new ol.Coordinate(0, 0),
c2: new ol.Coordinate(-45, 45),
cosineDistance: 6671.695598673524,
equirectangularDistance: 6812.398372654371,
finalBearing: 305.26438968275465,
haversineDistance: 6671.695598673525,
initialBearing: -35.264389682754654,
midpoint: new ol.Coordinate(-18.434948822922006, 24.0948425521107)
},
{
c1: new ol.Coordinate(0, 0),
c2: new ol.Coordinate(-45, -45),
cosineDistance: 6671.695598673524,
equirectangularDistance: 6812.398372654371,
finalBearing: 234.73561031724535,
haversineDistance: 6671.695598673525,
initialBearing: -144.73561031724535,
midpoint: new ol.Coordinate(-18.434948822922006, -24.0948425521107)
},
{
c1: new ol.Coordinate(0, 0),
c2: new ol.Coordinate(45, -45),
cosineDistance: 6671.695598673524,
equirectangularDistance: 6812.398372654371,
finalBearing: 125.26438968275465,
haversineDistance: 6671.695598673525,
initialBearing: 144.73561031724535,
midpoint: new ol.Coordinate(18.434948822922006, -24.0948425521107)
},
{
c1: new ol.Coordinate(0, 0),
c2: new ol.Coordinate(90, 180),
cosineDistance: 10007.543398010286,
equirectangularDistance: 20015.086796020572,
finalBearing: 90,
haversineDistance: 10007.543398010288,
initialBearing: -90,
midpoint: new ol.Coordinate(-45.00000000000005, 4.961398865471767e-15)
},
{
c1: new ol.Coordinate(0, 0),
c2: new ol.Coordinate(-90, 180),
cosineDistance: 10007.543398010286,
equirectangularDistance: 20015.086796020572,
finalBearing: 270,
haversineDistance: 10007.543398010288,
initialBearing: 90,
midpoint: new ol.Coordinate(45.00000000000005, 4.961398865471767e-15)
},
{
c1: new ol.Coordinate(0, 0),
c2: new ol.Coordinate(90, -180),
cosineDistance: 10007.543398010286,
equirectangularDistance: 20015.086796020572,
finalBearing: 90,
haversineDistance: 10007.543398010288,
initialBearing: -90.00000000000001,
midpoint: new ol.Coordinate(-45.00000000000005, -4.961398865471767e-15)
},
{
c1: new ol.Coordinate(0, 0),
c2: new ol.Coordinate(90, -180),
cosineDistance: 10007.543398010286,
equirectangularDistance: 20015.086796020572,
finalBearing: 90,
haversineDistance: 10007.543398010288,
initialBearing: -90.00000000000001,
midpoint: new ol.Coordinate(-45.00000000000005, -4.961398865471767e-15)
},
{
c1: new ol.Coordinate(45, 45),
c2: new ol.Coordinate(45, 45),
cosineDistance: 0,
equirectangularDistance: 0,
finalBearing: 180,
haversineDistance: 0,
initialBearing: 0,
midpoint: new ol.Coordinate(45.00000000000005, 45)
},
{
c1: new ol.Coordinate(45, 45),
c2: new ol.Coordinate(-45, 45),
cosineDistance: 6671.695598673525,
equirectangularDistance: 7076.401799751738,
finalBearing: 234.73561031724535,
haversineDistance: 6671.695598673525,
initialBearing: -54.73561031724535,
midpoint: new ol.Coordinate(0, 54.735610317245346)
},
{
c1: new ol.Coordinate(45, 45),
c2: new ol.Coordinate(-45, -45),
cosineDistance: 13343.391197347048,
equirectangularDistance: 14152.803599503475,
finalBearing: 234.73561031724535,
haversineDistance: 13343.391197347048,
initialBearing: -125.26438968275465,
midpoint: new ol.Coordinate(0, 0)
},
{
c1: new ol.Coordinate(45, 45),
c2: new ol.Coordinate(45, -45),
cosineDistance: 10007.543398010284,
equirectangularDistance: 10007.543398010286,
finalBearing: 180,
haversineDistance: 10007.543398010286,
initialBearing: 180,
midpoint: new ol.Coordinate(45.00000000000005, 0)
},
{
c1: new ol.Coordinate(45, 45),
c2: new ol.Coordinate(90, 180),
cosineDistance: 13343.39119734705,
equirectangularDistance: 15132.953174634127,
finalBearing: 35.264389682754654,
haversineDistance: 13343.391197347048,
initialBearing: -54.735610317245346,
midpoint: new ol.Coordinate(-45.00000000000005, 45.00000000000001)
},
{
c1: new ol.Coordinate(45, 45),
c2: new ol.Coordinate(-90, 180),
cosineDistance: 6671.695598673524,
equirectangularDistance: 16072.9523901477,
finalBearing: 324.73561031724535,
haversineDistance: 6671.695598673525,
initialBearing: 125.26438968275465,
midpoint: new ol.Coordinate(71.56505117707799, 24.094842552110702)
},
{
c1: new ol.Coordinate(45, 45),
c2: new ol.Coordinate(90, -180),
cosineDistance: 13343.39119734705,
equirectangularDistance: 25092.03003421417,
finalBearing: 35.264389682754654,
haversineDistance: 13343.391197347048,
initialBearing: -54.735610317245346,
midpoint: new ol.Coordinate(-45.00000000000005, 45)
},
{
c1: new ol.Coordinate(45, 45),
c2: new ol.Coordinate(90, -180),
cosineDistance: 13343.39119734705,
equirectangularDistance: 25092.03003421417,
finalBearing: 35.264389682754654,
haversineDistance: 13343.391197347048,
initialBearing: -54.735610317245346,
midpoint: new ol.Coordinate(-45.00000000000005, 45)
},
{
c1: new ol.Coordinate(-45, 45),
c2: new ol.Coordinate(-45, 45),
cosineDistance: 0,
equirectangularDistance: 0,
finalBearing: 180,
haversineDistance: 0,
initialBearing: 0,
midpoint: new ol.Coordinate(-45.00000000000005, 45)
},
{
c1: new ol.Coordinate(-45, 45),
c2: new ol.Coordinate(-45, -45),
cosineDistance: 10007.543398010284,
equirectangularDistance: 10007.543398010286,
finalBearing: 180,
haversineDistance: 10007.543398010286,
initialBearing: 180,
midpoint: new ol.Coordinate(-45.00000000000005, 0)
},
{
c1: new ol.Coordinate(-45, 45),
c2: new ol.Coordinate(45, -45),
cosineDistance: 13343.391197347048,
equirectangularDistance: 14152.803599503475,
finalBearing: 125.26438968275465,
haversineDistance: 13343.391197347048,
initialBearing: 125.26438968275465,
midpoint: new ol.Coordinate(0, 0)
},
{
c1: new ol.Coordinate(-45, 45),
c2: new ol.Coordinate(90, 180),
cosineDistance: 6671.695598673524,
equirectangularDistance: 16072.9523901477,
finalBearing: 35.264389682754654,
haversineDistance: 6671.695598673525,
initialBearing: -125.26438968275465,
midpoint: new ol.Coordinate(-71.56505117707799, 24.094842552110702)
},
{
c1: new ol.Coordinate(-45, 45),
c2: new ol.Coordinate(-90, 180),
cosineDistance: 13343.39119734705,
equirectangularDistance: 15132.953174634127,
finalBearing: 324.73561031724535,
haversineDistance: 13343.391197347048,
initialBearing: 54.735610317245346,
midpoint: new ol.Coordinate(45.00000000000005, 45.00000000000001)
},
{
c1: new ol.Coordinate(-45, 45),
c2: new ol.Coordinate(90, -180),
cosineDistance: 6671.695598673525,
equirectangularDistance: 25669.894779453065,
finalBearing: 35.264389682754654,
haversineDistance: 6671.695598673525,
initialBearing: -125.26438968275465,
midpoint: new ol.Coordinate(-71.56505117707799, 24.0948425521107)
},
{
c1: new ol.Coordinate(-45, 45),
c2: new ol.Coordinate(90, -180),
cosineDistance: 6671.695598673525,
equirectangularDistance: 25669.894779453065,
finalBearing: 35.264389682754654,
haversineDistance: 6671.695598673525,
initialBearing: -125.26438968275465,
midpoint: new ol.Coordinate(-71.56505117707799, 24.0948425521107)
},
{
c1: new ol.Coordinate(-45, -45),
c2: new ol.Coordinate(-45, -45),
cosineDistance: 0,
equirectangularDistance: 0,
finalBearing: 180,
haversineDistance: 0,
initialBearing: 0,
midpoint: new ol.Coordinate(-45.00000000000005, -45)
},
{
c1: new ol.Coordinate(-45, -45),
c2: new ol.Coordinate(45, -45),
cosineDistance: 6671.695598673525,
equirectangularDistance: 7076.401799751738,
finalBearing: 54.735610317245346,
haversineDistance: 6671.695598673525,
initialBearing: 125.26438968275465,
midpoint: new ol.Coordinate(0, -54.735610317245346)
},
{
c1: new ol.Coordinate(-45, -45),
c2: new ol.Coordinate(90, 180),
cosineDistance: 6671.695598673525,
equirectangularDistance: 25669.894779453065,
finalBearing: 144.73561031724535,
haversineDistance: 6671.695598673525,
initialBearing: -54.735610317245346,
midpoint: new ol.Coordinate(-71.56505117707799, -24.0948425521107)
},
{
c1: new ol.Coordinate(-45, -45),
c2: new ol.Coordinate(-90, 180),
cosineDistance: 13343.39119734705,
equirectangularDistance: 25092.03003421417,
finalBearing: 215.26438968275465,
haversineDistance: 13343.391197347048,
initialBearing: 125.26438968275465,
midpoint: new ol.Coordinate(45.00000000000005, -45)
},
{
c1: new ol.Coordinate(-45, -45),
c2: new ol.Coordinate(90, -180),
cosineDistance: 6671.695598673524,
equirectangularDistance: 16072.9523901477,
finalBearing: 144.73561031724535,
haversineDistance: 6671.695598673525,
initialBearing: -54.73561031724536,
midpoint: new ol.Coordinate(-71.56505117707799, -24.094842552110702)
},
{
c1: new ol.Coordinate(-45, -45),
c2: new ol.Coordinate(90, -180),
cosineDistance: 6671.695598673524,
equirectangularDistance: 16072.9523901477,
finalBearing: 144.73561031724535,
haversineDistance: 6671.695598673525,
initialBearing: -54.73561031724536,
midpoint: new ol.Coordinate(-71.56505117707799, -24.094842552110702)
},
{
c1: new ol.Coordinate(45, -45),
c2: new ol.Coordinate(45, -45),
cosineDistance: 0,
equirectangularDistance: 0,
finalBearing: 180,
haversineDistance: 0,
initialBearing: 0,
midpoint: new ol.Coordinate(45.00000000000005, -45)
},
{
c1: new ol.Coordinate(45, -45),
c2: new ol.Coordinate(90, 180),
cosineDistance: 13343.39119734705,
equirectangularDistance: 25092.03003421417,
finalBearing: 144.73561031724535,
haversineDistance: 13343.391197347048,
initialBearing: -125.26438968275465,
midpoint: new ol.Coordinate(-45.00000000000005, -45)
},
{
c1: new ol.Coordinate(45, -45),
c2: new ol.Coordinate(-90, 180),
cosineDistance: 6671.695598673525,
equirectangularDistance: 25669.894779453065,
finalBearing: 215.26438968275465,
haversineDistance: 6671.695598673525,
initialBearing: 54.735610317245346,
midpoint: new ol.Coordinate(71.56505117707799, -24.0948425521107)
},
{
c1: new ol.Coordinate(45, -45),
c2: new ol.Coordinate(90, -180),
cosineDistance: 13343.39119734705,
equirectangularDistance: 15132.953174634127,
finalBearing: 144.73561031724535,
haversineDistance: 13343.391197347048,
initialBearing: -125.26438968275465,
midpoint: new ol.Coordinate(-45.00000000000005, -45.00000000000001)
},
{
c1: new ol.Coordinate(45, -45),
c2: new ol.Coordinate(90, -180),
cosineDistance: 13343.39119734705,
equirectangularDistance: 15132.953174634127,
finalBearing: 144.73561031724535,
haversineDistance: 13343.391197347048,
initialBearing: -125.26438968275465,
midpoint: new ol.Coordinate(-45.00000000000005, -45.00000000000001)
},
{
c1: new ol.Coordinate(90, 180),
c2: new ol.Coordinate(90, 180),
cosineDistance: 0,
equirectangularDistance: 0,
finalBearing: 180,
haversineDistance: 0,
initialBearing: 0,
midpoint: new ol.Coordinate(-90, 7.0164775638926606e-15)
},
{
c1: new ol.Coordinate(90, 180),
c2: new ol.Coordinate(-90, 180),
cosineDistance: 20015.086796020572,
equirectangularDistance: 20015.086796020572,
finalBearing: 26.565051177077976,
haversineDistance: 20015.086796020572,
initialBearing: 153.43494882292202,
midpoint: new ol.Coordinate(-180, 63.43494882292201)
},
{
c1: new ol.Coordinate(90, 180),
c2: new ol.Coordinate(90, -180),
cosineDistance: 0,
equirectangularDistance: 40030.173592041145,
finalBearing: 0,
haversineDistance: 1.5603934160404731e-12,
initialBearing: 0,
midpoint: new ol.Coordinate(-90, 0)
},
{
c1: new ol.Coordinate(90, 180),
c2: new ol.Coordinate(90, -180),
cosineDistance: 0,
equirectangularDistance: 40030.173592041145,
finalBearing: 0,
haversineDistance: 1.5603934160404731e-12,
initialBearing: 0,
midpoint: new ol.Coordinate(-90, 0)
},
{
c1: new ol.Coordinate(-90, 180),
c2: new ol.Coordinate(-90, 180),
cosineDistance: 0,
equirectangularDistance: 0,
finalBearing: 180,
haversineDistance: 0,
initialBearing: 0,
midpoint: new ol.Coordinate(90, 7.0164775638926606e-15)
},
{
c1: new ol.Coordinate(-90, 180),
c2: new ol.Coordinate(90, -180),
cosineDistance: 20015.086796020572,
equirectangularDistance: 44755.09465146047,
finalBearing: 270,
haversineDistance: 20015.086796020572,
initialBearing: -90,
midpoint: new ol.Coordinate(-180, 0)
},
{
c1: new ol.Coordinate(-90, 180),
c2: new ol.Coordinate(90, -180),
cosineDistance: 20015.086796020572,
equirectangularDistance: 44755.09465146047,
finalBearing: 270,
haversineDistance: 20015.086796020572,
initialBearing: -90,
midpoint: new ol.Coordinate(-180, 0)
},
{
c1: new ol.Coordinate(90, -180),
c2: new ol.Coordinate(90, -180),
cosineDistance: 0,
equirectangularDistance: 0,
finalBearing: 180,
haversineDistance: 0,
initialBearing: 0,
midpoint: new ol.Coordinate(-90, -7.0164775638926606e-15)
},
{
c1: new ol.Coordinate(90, -180),
c2: new ol.Coordinate(90, -180),
cosineDistance: 0,
equirectangularDistance: 0,
finalBearing: 180,
haversineDistance: 0,
initialBearing: 0,
midpoint: new ol.Coordinate(-90, -7.0164775638926606e-15)
},
{
c1: new ol.Coordinate(90, -180),
c2: new ol.Coordinate(90, -180),
cosineDistance: 0,
equirectangularDistance: 0,
finalBearing: 180,
haversineDistance: 0,
initialBearing: 0,
midpoint: new ol.Coordinate(-90, -7.0164775638926606e-15)
}
];
describe('cosineDistance', function() {
it('results match Chris Veness\'s reference implementation', function() {
var e, i;
for (i = 0; i < expected.length; ++i) {
e = expected[i];
expect(sphere.cosineDistance(e.c1, e.c2)).toRoughlyEqual(
e.cosineDistance, 1e-9);
}
});
});
describe('equirectangularDistance', function() {
it('results match Chris Veness\'s reference implementation', function() {
var e, i;
for (i = 0; i < expected.length; ++i) {
e = expected[i];
expect(sphere.equirectangularDistance(e.c1, e.c2)).toRoughlyEqual(
e.equirectangularDistance, 1e-9);
}
});
});
describe('finalBearing', function() {
it('results match Chris Veness\'s reference implementation', function() {
var e, i;
for (i = 0; i < expected.length; ++i) {
e = expected[i];
expect(sphere.finalBearing(e.c1, e.c2)).toRoughlyEqual(
e.finalBearing, 1e-9);
}
});
});
describe('haversineDistance', function() {
it('results match Chris Veness\'s reference implementation', function() {
var e, i;
for (i = 0; i < expected.length; ++i) {
e = expected[i];
expect(sphere.haversineDistance(e.c1, e.c2)).toRoughlyEqual(
e.haversineDistance, 1e-9);
}
});
});
describe('initialBearing', function() {
it('results match Chris Veness\'s reference implementation', function() {
var e, i;
for (i = 0; i < expected.length; ++i) {
e = expected[i];
expect(sphere.initialBearing(e.c1, e.c2)).toRoughlyEqual(
e.initialBearing, 1e-9);
}
});
});
describe('midpoint', function() {
it('results match Chris Veness\'s reference implementation', function() {
var e, i;
for (i = 0; i < expected.length; ++i) {
e = expected[i];
midpoint = sphere.midpoint(e.c1, e.c2);
// Test modulo 360 to avoid unnecessary expensive modulo operations
// in our implementation.
expect(goog.math.modulo(midpoint.x, 360)).toRoughlyEqual(
goog.math.modulo(e.midpoint.x, 360), 1e-9);
expect(midpoint.y).toRoughlyEqual(e.midpoint.y, 1e-9);
}
});
});
});
goog.require('ol.Coordinate');
goog.require('ol.Sphere');