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Add the cardinal direction to articles (nearby article search). Fixes #83

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This commit is contained in:
mossroy 2014-04-10 14:17:54 +02:00
parent 8bff5cd843
commit 5d354dbd71
3 changed files with 688 additions and 643 deletions
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15
tests/tests.js
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@ -283,6 +283,21 @@ define(function(require) {
ok(rect1.contains(rect6), "rect1 should contain rect6");
ok(rect1.contains(rect7), "rect1 should contain rect7");
});
test("check bearing algorithm", function() {
var point1 = new geometry.point(0,0);
var point2 = new geometry.point(2,0);
var line1 = new geometry.line(point1, point2);
equal(line1.bearing(), "N", "Bearing of line1 should be N");
var pointLondon = new geometry.point(51.50777816772461, -0.12805555760860443);
var pointParis = new geometry.point(48.856614, 2.3522219000000177);
var pointAmsterdam = new geometry.point(52.326947, 4.741287);
var lineLondonParis = new geometry.line(pointLondon, pointParis);
var lineParisLondon = new geometry.line(pointParis, pointLondon);
var lineLondonAmsterdam = new geometry.line(pointLondon, pointAmsterdam);
equal(lineLondonParis.bearing(), "SE", "Bearing from London to Paris sould be SE");
equal(lineParisLondon.bearing(), "NW", "Bearing from Paris to London sould be NW");
equal(lineLondonAmsterdam.bearing(), "E", "Bearing from London to Amsterdam sould be E");
});
module("utils");
test("check reading an IEEE_754 float from 4 bytes" ,function() {

5
www/js/app.js
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@ -416,9 +416,10 @@ define(function(require) {
var distanceFromHereHtml = "";
if (title._geolocation && currentCoordinates) {
// If we know the current position and the title position, we display the distance
// If we know the current position and the title position, we display the distance and cardinal direction
var distanceKm = (currentCoordinates.distance(title._geolocation) * 6371 / 60).toFixed(1);
distanceFromHereHtml = " (" + distanceKm + " km)";
var cardinalDirection = currentCoordinates.bearing(title._geolocation);
distanceFromHereHtml = " (" + distanceKm + " km " + cardinalDirection + ")";
}
titleListDivHtml += "<a href='#' titleid='" + title.toStringId()

29
www/js/lib/geometry.js
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@ -96,6 +96,10 @@ define(function(require) {
distance: function(p) {
return line(this, p).length();
},
// Returns the bearing between me and point 'p'
bearing: function(p) {
return line(this, p).bearing();
},
// Returns a manhattan (taxi-cab) distance between me and point `p`.
manhattanDistance: function(p) {
return abs(p.x - this.x) + abs(p.y - this.y);
@ -245,6 +249,31 @@ define(function(require) {
}
return point(this.start.x + (alpha * pt1Dir.x / det),
this.start.y + (alpha * pt1Dir.y / det));
},
/**
* Returns the bearing (cardinal direction) of the line. For example N, W, or SE
* @returns {String} One of the following bearings : NE, E, SE, S, SW, W, NW, N
*/
bearing: function() {
var lat1 = this.start.x * Math.PI / 180;
var lat2 = this.end.x * Math.PI / 180;
var lon1 = this.start.y * Math.PI / 180;
var lon2 = this.end.y * Math.PI / 180;
var dLon = lon2 - lon1;
var y = Math.sin(dLon) * Math.cos(lat2);
var x = Math.cos(lat1) * Math.sin(lat2) -
Math.sin(lat1) * Math.cos(lat2) * Math.cos(dLon);
var brng = Math.atan2(y, x) / Math.PI * 180;
var bearings = ["NE", "E", "SE", "S", "SW", "W", "NW", "N"];
var index = brng - 22.5;
if (index < 0)
index += 360;
index = parseInt(index / 45);
return(bearings[index]);
}
};