From e34e299fd01343ff3341776c47e8d773dc3ca35e Mon Sep 17 00:00:00 2001 From: Bryan Housel Date: Mon, 23 Jun 2014 17:12:02 -0400 Subject: [PATCH] add dLat/dLon <-> meters tests, narrower limits for distance tests. --- test/spec/geo.js | 82 +++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 77 insertions(+), 5 deletions(-) diff --git a/test/spec/geo.js b/test/spec/geo.js index a6a86ecb2..555ec78db 100644 --- a/test/spec/geo.js +++ b/test/spec/geo.js @@ -57,6 +57,78 @@ describe('iD.geo', function() { }); }); + describe('.latToMeters', function() { + it('0 degrees latitude is 0 meters', function() { + expect(iD.geo.latToMeters(0)).to.eql(0); + }); + it('1 degree latitude is approx 111 km', function() { + expect(iD.geo.latToMeters(1)).to.be.within(110E3, 112E3); + }); + it('-1 degree latitude is approx -111 km', function() { + expect(iD.geo.latToMeters(-1)).to.be.within(-112E3, -110E3); + }); + }); + + describe('.lonToMeters', function() { + it('0 degrees longitude is 0 km', function() { + expect(iD.geo.lonToMeters(0, 0)).to.eql(0); + }); + it('distance of 1 degree longitude varies with latitude', function() { + expect(iD.geo.lonToMeters(1, 0)).to.be.within(110E3, 112E3); + expect(iD.geo.lonToMeters(1, 15)).to.be.within(107E3, 108E3); + expect(iD.geo.lonToMeters(1, 30)).to.be.within(96E3, 97E3); + expect(iD.geo.lonToMeters(1, 45)).to.be.within(78E3, 79E3); + expect(iD.geo.lonToMeters(1, 60)).to.be.within(55E3, 56E3); + expect(iD.geo.lonToMeters(1, 75)).to.be.within(28E3, 29E3); + expect(iD.geo.lonToMeters(1, 90)).to.eql(0); + }); + it('distance of -1 degree longitude varies with latitude', function() { + expect(iD.geo.lonToMeters(-1, 0)).to.be.within(-112E3, -110E3); + expect(iD.geo.lonToMeters(-1, -15)).to.be.within(-108E3, -107E3); + expect(iD.geo.lonToMeters(-1, -30)).to.be.within(-97E3, -96E3); + expect(iD.geo.lonToMeters(-1, -45)).to.be.within(-79E3, -78E3); + expect(iD.geo.lonToMeters(-1, -60)).to.be.within(-56E3, -55E3); + expect(iD.geo.lonToMeters(-1, -75)).to.be.within(-29E3, -28E3); + expect(iD.geo.lonToMeters(-1, -90)).to.eql(0); + }); + }); + + describe('.metersToLat', function() { + it('0 meters is 0 degrees latitude', function() { + expect(iD.geo.metersToLat(0)).to.eql(0); + }); + it('111 km is approx 1 degree latitude', function() { + expect(iD.geo.metersToLat(111E3)).to.be.within(0.995, 1.005); + }); + it('-111 km is approx -1 degree latitude', function() { + expect(iD.geo.metersToLat(-111E3)).to.be.within(-1.005, -0.995); + }); + }); + + describe('.metersToLon', function() { + it('0 meters is 0 degrees longitude', function() { + expect(iD.geo.metersToLon(0, 0)).to.eql(0); + }); + it('distance of 1 degree longitude varies with latitude', function() { + expect(iD.geo.metersToLon(111320, 0)).to.be.within(0.995, 1.005); + expect(iD.geo.metersToLon(107551, 15)).to.be.within(0.995, 1.005); + expect(iD.geo.metersToLon(96486, 30)).to.be.within(0.995, 1.005); + expect(iD.geo.metersToLon(78847, 45)).to.be.within(0.995, 1.005); + expect(iD.geo.metersToLon(55800, 60)).to.be.within(0.995, 1.005); + expect(iD.geo.metersToLon(28902, 75)).to.be.within(0.995, 1.005); + expect(iD.geo.metersToLon(1, 90)).to.eql(0); + }); + it('distance of -1 degree longitude varies with latitude', function() { + expect(iD.geo.metersToLon(-111320, 0)).to.be.within(-1.005, -0.995); + expect(iD.geo.metersToLon(-107551, 15)).to.be.within(-1.005, -0.995); + expect(iD.geo.metersToLon(-96486, 30)).to.be.within(-1.005, -0.995); + expect(iD.geo.metersToLon(-78847, 45)).to.be.within(-1.005, -0.995); + expect(iD.geo.metersToLon(-55800, 60)).to.be.within(-1.005, -0.995); + expect(iD.geo.metersToLon(-28902, 75)).to.be.within(-1.005, -0.995); + expect(iD.geo.metersToLon(-1, 90)).to.eql(0); + }); + }); + describe('.sphericalDistance', function() { it('distance between two same points is zero', function() { var a = [0, 0], @@ -66,22 +138,22 @@ describe('iD.geo', function() { it('a straight 1 degree line at the equator is aproximately 111 km', function() { var a = [0, 0], b = [1, 0]; - expect(iD.geo.sphericalDistance(a, b)).to.be.within(100E3,120E3); + expect(iD.geo.sphericalDistance(a, b)).to.be.within(110E3, 112E3); }); - it('a pythagorean triangle is right', function() { + it('a pythagorean triangle is (nearly) right', function() { var a = [0, 0], b = [4, 3]; - expect(iD.geo.sphericalDistance(a, b)).to.be.within(500E3,600E3); + expect(iD.geo.sphericalDistance(a, b)).to.be.within(555E3, 556E3); }); it('east-west distances at high latitude are shorter', function() { var a = [0, 60], b = [1, 60]; - expect(iD.geo.sphericalDistance(a, b)).to.be.within(50E3,60E3); + expect(iD.geo.sphericalDistance(a, b)).to.be.within(55E3, 56E3); }); it('north-south distances at high latitude are not shorter', function() { var a = [0, 60], b = [0, 61]; - expect(iD.geo.sphericalDistance(a, b)).to.be.within(100E3,120E3); + expect(iD.geo.sphericalDistance(a, b)).to.be.within(110E3, 112E3); }); });