Function for getting great circle lengths

2017-08-10 17:45:22 -06:00
parent 445c157ee3
commit 92c62e5432
5 changed files with 212 additions and 18 deletions
--- a/test/spec/ol/sphere.test.js
+++ b/test/spec/ol/sphere.test.js
@@ -0,0 +1,179 @@
+// See http://www.movable-type.co.uk/scripts/latlong.html
+// FIXME add tests for offset
+
+goog.provide('ol.test.Sphere');
+
+goog.require('ol.Sphere');
+goog.require('ol.format.WKT');
+goog.require('ol.proj.EPSG4326');
+
+
+describe('ol.Sphere', function() {
+
+  var sphere = new ol.Sphere(6371);
+  var expected = [{
+    c1: [0, 0],
+    c2: [0, 0],
+    haversineDistance: 0
+  }, {
+    c1: [0, 0],
+    c2: [45, 45],
+    haversineDistance: 6671.695598673525
+  }, {
+    c1: [0, 0],
+    c2: [-45, 45],
+    haversineDistance: 6671.695598673525
+  }, {
+    c1: [0, 0],
+    c2: [-45, -45],
+    haversineDistance: 6671.695598673525
+  }, {
+    c1: [0, 0],
+    c2: [45, -45],
+    haversineDistance: 6671.695598673525
+  }, {
+    c1: [45, 45],
+    c2: [45, 45],
+    haversineDistance: 0
+  }, {
+    c1: [45, 45],
+    c2: [-45, 45],
+    haversineDistance: 6671.695598673525
+  }, {
+    c1: [45, 45],
+    c2: [-45, -45],
+    haversineDistance: 13343.391197347048
+  }, {
+    c1: [45, 45],
+    c2: [45, -45],
+    haversineDistance: 10007.543398010286
+  }, {
+    c1: [-45, 45],
+    c2: [-45, 45],
+    haversineDistance: 0
+  }, {
+    c1: [-45, 45],
+    c2: [-45, -45],
+    haversineDistance: 10007.543398010286
+  }, {
+    c1: [-45, 45],
+    c2: [45, -45],
+    haversineDistance: 13343.391197347048
+  }, {
+    c1: [-45, -45],
+    c2: [-45, -45],
+    haversineDistance: 0
+  }, {
+    c1: [-45, -45],
+    c2: [45, -45],
+    haversineDistance: 6671.695598673525
+  }, {
+    c1: [45, -45],
+    c2: [45, -45],
+    haversineDistance: 0
+  }];
+
+  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)).to.roughlyEqual(
+            e.haversineDistance, 1e-9);
+      }
+    });
+
+  });
+
+  describe('Vincenty area', function() {
+    var geometry;
+    before(function(done) {
+      afterLoadText('spec/ol/format/wkt/illinois.wkt', function(wkt) {
+        try {
+          var format = new ol.format.WKT();
+          geometry = format.readGeometry(wkt);
+        } catch (e) {
+          done(e);
+        }
+        done();
+      });
+    });
+
+    it('results match the expected area of Ilinois', function() {
+      var coords = geometry.getPolygon(0).getLinearRing(0).getCoordinates();
+      var sphere = new ol.Sphere(ol.proj.EPSG4326.RADIUS);
+      expect(sphere.geodesicArea(coords)).to.equal(145978332359.37125);
+    });
+  });
+
+});
+
+describe('ol.Sphere.getLength()', function() {
+  var cases = [{
+    geometry: new ol.geom.Point([0, 0]),
+    length: 0
+  }, {
+    geometry: new ol.geom.MultiPoint([[0, 0], [1, 1]]),
+    length: 0
+  }, {
+    geometry: new ol.geom.LineString([
+      [12801741.441226462, -3763310.627144653],
+      [14582853.293918837, -2511525.2348457114],
+      [15918687.18343812, -2875744.624352243],
+      [16697923.618991036, -4028802.0261344076]
+    ]),
+    length: 4407939.124914191
+  }, {
+    geometry: new ol.geom.LineString([
+      [115, -32],
+      [131, -22],
+      [143, -25],
+      [150, -34]
+    ]),
+    options: {projection: 'EPSG:4326'},
+    length: 4407939.124914191
+  }, {
+    geometry: new ol.geom.MultiLineString([
+      [
+        [115, -32],
+        [131, -22],
+        [143, -25],
+        [150, -34]
+      ], [
+        [115, -32],
+        [131, -22],
+        [143, -25],
+        [150, -34]
+      ]
+    ]),
+    options: {projection: 'EPSG:4326'},
+    length: 2 * 4407939.124914191
+  }, {
+    geometry: new ol.geom.GeometryCollection([
+      new ol.geom.LineString([
+        [115, -32],
+        [131, -22],
+        [143, -25],
+        [150, -34]
+      ]),
+      new ol.geom.LineString([
+        [115, -32],
+        [131, -22],
+        [143, -25],
+        [150, -34]
+      ])
+    ]),
+    options: {projection: 'EPSG:4326'},
+    length: 2 * 4407939.124914191
+  }];
+
+  cases.forEach(function(c, i) {
+    it('works for case ' + i, function() {
+      var c = cases[i];
+      var length = ol.Sphere.getLength(c.geometry, c.options);
+      expect(length).to.equal(c.length);
+    });
+  });
+
+});