Gerade noch so unter 100 Zeilen

main.js

$(document).ready(function () {
    var obj = {};
    obj.jqxhr = $.getJSON('/data/styles.json', function () {
    }).done(function (data) {
        obj.styles = data;
    });
    obj.curvature = 0.5;
    obj.markers = [];
    obj.bounds = new google.maps.LatLngBounds();
    obj.curveMarker = null;
    obj.icon = '';
    obj.map = new google.maps.Map(document.getElementById('map-canvas'), {
        zoom: 2,
        zoomControl: false,
        scaleControl: false,
        scrollwheel: false,
        disableDoubleClickZoom: true,
        streetViewControl: false,
        rotateControl: false,
        panControl: false,
        draggable: false

    });
    obj.bounds = new google.maps.LatLngBounds();
    obj.iw = new google.maps.InfoWindow();
    obj.jqxhr = $.getJSON('/data/usergroups.json', function () {
    }).done(function (data) {
        $.each(data, function (key, val) {
            //var id = val.id;
            //var html = '<p>' + val.name + '</p>';
            var latlng = new google.maps.LatLng(val.adr.geo['lat'], val.adr.geo['lng']);
            var marker = new google.maps.Marker({
                position: latlng,
                map: obj.map,
                draggable: false,
                icon: {
                    path: google.maps.SymbolPath.CIRCLE,
                    fillOpacity: 1.0,
                    fillColor: val.ico.fill.toString(),
                    strokeOpacity: 1.0,
                    strokeColor: val.ico.stroke.toString(),
                    strokeWeight: 2.0,
                    scale: parseFloat(val.ico.scale)
                },
                zIndex: parseInt(val.id),
                id: val.id,
                title: val.name,
                desc: val.sum
            });
            obj.bounds.extend(marker.position);
            marker.setMap(obj.map);
            obj.markers.push(marker);

            google.maps.event.addListener(marker, 'click', function () {
            });
        });
        obj.map.fitBounds(obj.bounds);
        obj.map.setOptions({styles: obj.styles});
        google.maps.event.addListener(obj.map, 'projection_changed', function () {
            addCurveMarkers();
        });

        function addCurveMarkers() {
            var projection = obj.map.getProjection();
            var curr, next, prev, e, m, o, c, pos1, pos2, p1, p2, pathDef, scale, symbol;
            var l = obj.markers.length;
            for (var i = 0; i < l; i++) {
                if (i + 1 == l) break;
                curr = obj.markers[i];
                prev = obj.markers[(i + l - 1) % l];
                next = obj.markers[(i + 1) % l];
                pos1 = curr.getPosition();
                pos2 = next.getPosition();
                p1 = projection.fromLatLngToPoint(pos1);
                p2 = projection.fromLatLngToPoint(pos2);
                e = new google.maps.Point(p2.x - p1.x, p2.y - p1.y);
                m = new google.maps.Point(e.x / 2, e.y / 2);
                o = new google.maps.Point(e.y, -e.x);
                c = new google.maps.Point(m.x + obj.curvature * o.x, m.y + obj.curvature * o.y);
                pathDef = 'M 0,0 ' + 'q ' + c.x + ',' + c.y + ' ' + e.x + ',' + e.y;
                scale = 1 / (Math.pow(2, -obj.map.getZoom()));
                symbol = {
                    path: pathDef,
                    scale: scale,
                    strokeWeight: 3,
                    strokeColor: curr.icon.strokeColor
                };
                obj.curveMarker = new google.maps.Marker({
                    position: pos1,
                    clickable: false,
                    icon: symbol,
                    zIndex: 0,
                    map: obj.map
                });
            }
        }
    });
});