Created
November 28, 2018 05:06
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calculate distance
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function distance(lat1, lon1, lat2, lon2, unit) { | |
if ((lat1 == lat2) && (lon1 == lon2)) { | |
return 0; | |
} | |
else { | |
var radlat1 = Math.PI * lat1/180; | |
var radlat2 = Math.PI * lat2/180; | |
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); | |
if (dist > 1) { | |
dist = 1; | |
} | |
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; | |
} | |
} |
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