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Calculate distance from user given a lattitde and longitude
/* global App:false */
'use strict';
var Lib = Lib || {};
Lib.DistanceView = Backbone.View.extend({
latitude: 0,
longitude: 0,
initialize: function(){
this.latitude = this.$el.data('lat');
this.longitude = this.$el.data('long');
_.bindAll(this, 'render', 'gotCoordinates');
if(navigator.geolocation){
navigator.geolocation.getCurrentPosition(this.gotCoordinates, this.failedToGetCoordinates);
}
},
gotCoordinates: function(position){
this.updateDistance(this.calculateDistance(this.latitude, this.longitude, position.coords.latitude, position.coords.longitude, 'K'));
},
calculateDistance: function(lat1, lon1, lat2, lon2, unit){
var theta = lon1 - lon2;
var dist = Math.sin(this.deg2rad(lat1)) * Math.sin(this.deg2rad(lat2)) + Math.cos(this.deg2rad(lat1)) * Math.cos(this.deg2rad(lat2)) * Math.cos(this.deg2rad(theta));
dist = Math.acos(dist);
dist = this.rad2deg(dist);
var miles = dist * 60 * 1.1515;
unit = unit.toUpperCase();
if (unit === 'K') {
return Math.round((miles * 1.609344) * 100) / 100;
} else if (unit === 'N') {
return (miles * 0.8684);
} else {
return miles;
}
},
updateDistance: function(distance){
this.$el.find('.distance-in-km').html(distance);
},
failedToGetCoordinates: function(error){
if(error.code === 1){
console.log('Geolocation Access Denied');
}
},
deg2rad: function(deg){
return deg * (Math.PI / 180);
},
rad2deg: function(rad){
return rad * (180 / Math.PI);
}
});
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