Google Maps API - Closest marker function change to closest n markers

Question

I am using the formula found in this question to find the closest marker on the map to the current position. I would like to modify this formula so that it finds the closet n number of locations(closest 5 locations, closest 10 locations, etc.) and I am not sure how to accomplish this.

Here is the modified formula I am using:

function rad(x) {return x*Math.PI/180;}
function find_closest_marker(center, map) {
    var lat = center.lat();
    var lng = center.lng();
    var R = 6371; // radius of earth in km
    var distances = [];
    var closest = -1;
    for( i=0;i<markers.length; i++ ) {
        var mlat = markers[i].position.lat();
        var mlng = markers[i].position.lng();
        var dLat  = rad(mlat - lat);
        var dLong = rad(mlng - lng);
        var a = Math.sin(dLat/2) * Math.sin(dLat/2) +
            Math.cos(rad(lat)) * Math.cos(rad(lat)) * Math.sin(dLong/2) * Math.sin(dLong/2);
        var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
        var d = R * c;
        distances[i] = d;
        if ( closest == -1 || d < distances[closest] ) {
            closest = i;
        }
    }

    //Log title of closest marker
    console.log(markers[closest].title);
}

Here is how I am loading the markers:

// Add markers to the map
function setMarkers(center, map) {
    var json = (function () { 
        var json = null; 
        $.ajax({ 
            'async': false, 
            'global': false, 
            'url': "js/data.json", 
            'dataType': "json", 
            'success': function (data) {
                 json = data; 
             }
        });
        return json;
    })();
    // Loop over each of the json elements
    for (var i = 0, length = json.length; i < length; i++) {
        var data = json[i],
        latLng = new google.maps.LatLng(data.lat, data.lon);
        // Create a marker and place it on the map
        var icon = 'assets/marker.png';
        var marker = new google.maps.Marker({
            position: latLng,
            map: map,
            icon: icon,
            title: data.loc
        });
        markers.push(marker);
        infoBox(map, marker, data);
    }
}

How can I modify the formula further so that it finds the closest n number of markers rather than just the single closest one?

Answer 1

You could use the (slightly modified) findClosestN function from this question (changed gmarkers to markers, changed the function to return the closest array limited to numberOfResults elements)

function findClosestN(pt, numberOfResults) {
    var closest = [];
    for (var i = 0; i < markers.length; i++) {
        markers[i].distance = google.maps.geometry.spherical.computeDistanceBetween(pt, markers[i].getPosition());
        markers[i].setMap(null);
        closest.push(markers[i]);
    }
    closest.sort(sortByDist);
    return closest.splice(0,numberOfResults);
}

function sortByDist(a, b) {
    return (a.distance - b.distance)
}

proof of concept fiddle