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ederoyd46/GeoLocation.js

Created May 5, 2012 20:01
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Revisions

  1. ederoyd46 revised this gist May 5, 2012. 1 changed file with 34 additions and 34 deletions.
    68 changes: 34 additions & 34 deletions GeoLocation.js
    View file
    Original file line number Diff line number Diff line change
    @@ -49,40 +49,40 @@ var GeoLocation = GeoLocation ? GeoLocation : {
    },

    boundingCoordinates: function(location, distance) {
    if (!location || distance < 0) {
    console.log("no location or distance");
    return;
    }
    var radius = GeoLocation.EARTH_RADIUS;
    var radDist = distance / radius;
    var minLat = location.radLat - radDist;
    var maxLat = location.radLat + radDist;
    if (!location || distance < 0) {
    console.log("no location or distance");
    return;
    }
    var radius = GeoLocation.EARTH_RADIUS;
    var radDist = distance / radius;
    var minLat = location.radLat - radDist;
    var maxLat = location.radLat + radDist;

    var minLon, maxLon;
    if (minLat > GeoLocation.MIN_LAT() && maxLat < GeoLocation.MAX_LAT()) {
    var deltaLon = Math.asin(Math.sin(radDist) / Math.cos(location.radLat));
    minLon = location.radLon - deltaLon;
    if (minLon < GeoLocation.MIN_LON()) minLon += 2 * Math.PI;
    maxLon = location.radLon + deltaLon;
    if (maxLon > GeoLocation.MAX_LON()) maxLon -= 2 * Math.PI;
    } else {
    // a pole is within the distance
    minLat = Math.max(minLat, GeoLocation.MIN_LAT());
    maxLat = Math.min(maxLat, GeoLocation.MAX_LAT());
    minLon = GeoLocation.MIN_LON();
    maxLon = GeoLocation.MAX_LON();
    }
    var locationRange = { lat: location.degLat
    , lon: location.degLon
    , minLat: GeoLocation.radianToDegree(minLat)
    , maxLat: GeoLocation.radianToDegree(maxLat)
    , minLon: GeoLocation.radianToDegree(minLon)
    , maxLon: GeoLocation.radianToDegree(maxLon)
    };
    return locationRange;
    }
    var minLon, maxLon;
    if (minLat > GeoLocation.MIN_LAT() && maxLat < GeoLocation.MAX_LAT()) {
    var deltaLon = Math.asin(Math.sin(radDist) / Math.cos(location.radLat));
    minLon = location.radLon - deltaLon;
    if (minLon < GeoLocation.MIN_LON()) minLon += 2 * Math.PI;
    maxLon = location.radLon + deltaLon;
    if (maxLon > GeoLocation.MAX_LON()) maxLon -= 2 * Math.PI;
    } else {
    // a pole is within the distance
    minLat = Math.max(minLat, GeoLocation.MIN_LAT());
    maxLat = Math.min(maxLat, GeoLocation.MAX_LAT());
    minLon = GeoLocation.MIN_LON();
    maxLon = GeoLocation.MAX_LON();
    }
    var locationRange = { lat: location.degLat
    , lon: location.degLon
    , minLat: GeoLocation.radianToDegree(minLat)
    , maxLat: GeoLocation.radianToDegree(maxLat)
    , minLon: GeoLocation.radianToDegree(minLon)
    , maxLon: GeoLocation.radianToDegree(maxLon)
    };
    return locationRange;
    }

    }
  2. ederoyd46 created this gist May 5, 2012.
    88 changes: 88 additions & 0 deletions GeoLocation.js
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,88 @@
    //Javascript for finding latitude and longitude range boundaries.
    //Based on the excellent Java example by http://janmatuschek.de/LatitudeLongitudeBoundingCoordinates

    var GeoLocation = GeoLocation ? GeoLocation : {
    TO_RADIAN: 0.0174532925,
    TO_DEGREE: 57.2957795,
    EARTH_RADIUS: 6371.01,
    TO_MILE: 0.621371192,
    TO_KM: 1.609344,
    MIN_LAT: function() { return GeoLocation.degreeToRadian(-90) },
    MAX_LAT: function() { return GeoLocation.degreeToRadian(90) },
    MIN_LON: function() { return GeoLocation.degreeToRadian(-180) },
    MAX_LON: function() { return GeoLocation.degreeToRadian(180) },

    degreeToRadian: function (degree) { return degree * GeoLocation.TO_RADIAN },
    radianToDegree: function (radian) { return radian * GeoLocation.TO_DEGREE },
    kmToMile: function (km) {return km * GeoLocation.TO_MILE },
    mileToKm: function (mile) {return mile * GeoLocation.TO_KM },

    buildLocationRange: function(latitude, longitude, boundaryInMiles) {
    var degLat = latitude;
    var degLon = longitude;
    var radLat = GeoLocation.degreeToRadian(degLat);
    var radLon = GeoLocation.degreeToRadian(degLon);

    var location = { degLat: degLat
    , degLon: degLon
    , radLat: radLat
    , radLon: radLon
    };

    GeoLocation.checkBounds(location);
    var locationRange = GeoLocation.boundingCoordinates(location, GeoLocation.mileToKm(boundaryInMiles));

    return locationRange;
    },

    checkBounds: function(location) {
    if (location.radLat < GeoLocation.MIN_LAT || location.radLat > GeoLocation.MAX_LAT ||
    location.radLon < GeoLocation.MIN_LON || location.radLon > GeoLocation.MAX_LON) {
    console.log("radLat or radLon is out of bounds");
    }
    },

    distance: function(location1, location2) {
    return Math.acos(Math.sin(location1.radLat) * Math.sin(location2.radLat) +
    Math.cos(location1.radLat) * Math.cos(location2.radLat) *
    Math.cos(location1.radLon - location2.radLon)) * GeoLocation.EARTH_RADIUS;
    },

    boundingCoordinates: function(location, distance) {
    if (!location || distance < 0) {
    console.log("no location or distance");
    return;
    }

    var radius = GeoLocation.EARTH_RADIUS;
    var radDist = distance / radius;
    var minLat = location.radLat - radDist;
    var maxLat = location.radLat + radDist;

    var minLon, maxLon;

    if (minLat > GeoLocation.MIN_LAT() && maxLat < GeoLocation.MAX_LAT()) {
    var deltaLon = Math.asin(Math.sin(radDist) / Math.cos(location.radLat));
    minLon = location.radLon - deltaLon;
    if (minLon < GeoLocation.MIN_LON()) minLon += 2 * Math.PI;
    maxLon = location.radLon + deltaLon;
    if (maxLon > GeoLocation.MAX_LON()) maxLon -= 2 * Math.PI;
    } else {
    // a pole is within the distance
    minLat = Math.max(minLat, GeoLocation.MIN_LAT());
    maxLat = Math.min(maxLat, GeoLocation.MAX_LAT());
    minLon = GeoLocation.MIN_LON();
    maxLon = GeoLocation.MAX_LON();
    }

    var locationRange = { lat: location.degLat
    , lon: location.degLon
    , minLat: GeoLocation.radianToDegree(minLat)
    , maxLat: GeoLocation.radianToDegree(maxLat)
    , minLon: GeoLocation.radianToDegree(minLon)
    , maxLon: GeoLocation.radianToDegree(maxLon)
    };
    return locationRange;
    }

    }