Find closest city to given longitude/latitude [closed]

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Closed 6 years ago.

I have a set of 10 citys and want to find out which one is the closest to a given longitude/latitude.

Any ideas how to do that using javascript?

thx. rttmax

回答1:

From this site, you can use the Haversine formula:

a = sin²(Δφ/2) + cos(φ1).cos(φ2).sin²(Δλ/2)
c = 2.atan2(√a, √(1−a))
d = R.c

Which can be implemented in Javascript:

var R = 6371; // km
var dLat = (lat2-lat1).toRad();
var dLon = (lon2-lon1).toRad();
var lat1 = lat1.toRad();
var lat2 = lat2.toRad();

var a = Math.sin(dLat/2) * Math.sin(dLat/2) +
    Math.sin(dLon/2) * Math.sin(dLon/2) * Math.cos(lat1) * Math.cos(lat2); 
var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
var d = R * c;

Then just do that for all of the cities using a loop and find the smallest.

来源：https://stackoverflow.com/questions/17594401/find-closest-city-to-given-longitude-latitude