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Get the distance between two lat-long points
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// Option 1 | |
function distance(lat1, lon1, lat2, lon2, unit) { | |
var radlat1 = Math.PI * lat1/180 | |
var radlat2 = Math.PI * lat2/180 | |
var radlon1 = Math.PI * lon1/180 | |
var radlon2 = Math.PI * lon2/180 | |
var theta = lon1-lon2 | |
var radtheta = Math.PI * theta/180 | |
var dist = Math.sin(radlat1) * Math.sin(radlat2) + Math.cos(radlat1) * Math.cos(radlat2) * Math.cos(radtheta); | |
dist = Math.acos(dist) | |
dist = dist * 180/Math.PI | |
dist = dist * 60 * 1.1515 | |
if (unit=="K") { dist = dist * 1.609344 } | |
if (unit=="N") { dist = dist * 0.8684 } | |
return dist | |
} | |
// Option 2 | |
function 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; | |
} | |
function deg2rad(deg) { | |
return deg * (Math.PI/180) | |
} |
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