Google地图-获取英国县的坐标

Question

I was wondering whether anyone could please advise how I can get the coordinates for UK counties to be able to add a polygon to google maps using the google maps API?

I have looked at using https://nominatim.openstreetmap.org/details.php?place_id=198164455 to retrieve the OSM relation to be able to use http://polygons.openstreetmap.fr/

For example: Leicestershire OSM = 189890

http://polygons.openstreetmap.fr/index.py?id=189890

I have used the coordinates for the area however I believe these are incorrect since the polygon appears in the middle of the sea rather than over the county.

Can anyone please advise how I can get the coordinates for the UK counties to be able to add the polygon? I wasn't sure whether there are any tools that would generate these for you?

My code: ( var leicestershire should have the coordinates of the county )

function initialize() {

        var pin = new google.maps.LatLng(52.374490, -0.713289);

        var map = new google.maps.Map(document.getElementById('map-canvas'), {
            zoom: 5,
            //minZoom: 15,
            //maxZoom: 15,
            center: pin,
            mapTypeId: google.maps.MapTypeId.ROADMAP,
            overviewMapControl:true,
            mapTypeControl:false,
            zoomControl: true,
            streetViewControl: false,
            draggable: true
        });
        var marker = new google.maps.Marker({
          position: pin,
          map: map
        });

        var leicestershire = [];
        var leicestershirePoly = [];


        leicestershire.forEach(function(coordinate) {
            var latlng = coordinate.split(",");


            var lat =  parseFloat(latlng[0]);
            var lng = parseFloat(latlng[1]);

            if(!isNaN(lat) && !isNaN(lng)) {
                leicestershirePoly.push({lat: lat, lng: lng});
            }else{
                console.log(coordinate);
            }
        });


        var leicesterRegion = new google.maps.Polygon({
            paths: leicestershirePoly,
            strokeColor: '#FF0000',
            strokeOpacity: 0.8,
            strokeWeight: 2,
            fillColor: '#FF0000',
            fillOpacity: 0.35
        });
        leicesterRegion.setMap(map);

    }

    google.maps.event.addDomListener(window, 'load', initialize);

Answer 1

Leicestershire resolves to 52.772571, -1.2052126 in Google Maps. The first line of coordinates in your example polygon is -1.5975472, 52.7004047 so obviously, latitude and longitude are inverted.

In your forEach loop, replace

var lat = parseFloat(latlng[0]);
var lng = parseFloat(latlng[1]);

by

var lat = parseFloat(latlng[1]);
var lng = parseFloat(latlng[0]);

That should be enough to fix the issue if the rest of your code is working.