locations

sorting of locations ref. nearest location.

sort locations with nearest distance

how it works?

• get user’s current location
• compare with other destinations
• sort according the nearest

there are two ways to compare distance

personally, i like haversine formula and have been using it.

algorithm 1

use havesine formula.

haversine formula

double getdistancefromlatloninkm(lat1,lon1,lat2,lon2) {
  var r = 6371; // radius of the earth in km
  var dlat = deg2rad(lat2-lat1);  // deg2rad below
  var dlon = deg2rad(lon2-lon1);
  var a =
      math.sin(dlat/2) * math.sin(dlat/2) +
          math.cos(deg2rad(lat1)) * math.cos(deg2rad(lat2)) *
              math.sin(dlon/2) * math.sin(dlon/2)
  ;
  var c = 2 * math.atan2(math.sqrt(a), math.sqrt(1-a));
  var d = r * c; // distance in km
  return d;
}

double deg2rad(deg) {
  return deg * (math.pi/180);
}

algorithm 2

use inbuilt distance comparision function provided by geolocater.

geolocator.distancebetween(source.latitude,source.longitude, destination.latitude,destination.longitude);

assumption”

• you are in google plex (37.422,-122.084)

destinations:

• destination(37.4274684,-122.1698161, “standford university”),
• destination(37.4083327,-122.0776016, “taco bell”),
• destination(37.4259071,-122.1095606, “ramos park”),
• destination(37.8711583,-122.336457, “bekerly”),
• destination(37.7586968,-122.3053474, “oakland”),
• destination(37.4420794,-122.1432758, “palo alto”),
• destination(37.5206515,-122.064364, “new wark”)

output:

haversine algorithm	geolocator algorithm