google-maps - 谷歌地图如何在最近的道路上强制标记

Question

我正在做一个车辆跟踪项目，我正在从数据库中获取坐标，并显示在谷歌地图上。这是我的代码......!!

function get_coordinates(checkbox){
    var v_id=checkbox.id;
    if(checkbox.checked){
        var hr = new XMLHttpRequest();
        hr.open("POST", "fetch_coordinates.php", true);
        hr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
        hr.onreadystatechange = function() {
            if(hr.readyState == 4 && hr.status == 200) {
                var data = JSON.parse(hr.responseText);
                var lat=data.loc.lat;
                var lon=data.loc.lon;
                addmarker(lat,lon,v_id);
            }
        }
         hr.send("id="+v_id);   
    } else{
        var mark = markers[v_id]; // find the marker by given id
        mark.setMap(null);
        delete markers[v_id];

    }    
}
function addmarker(lat,lon,v_id){
    var marker = new google.maps.Marker({
        id: v_id,
        position: new google.maps.LatLng(lat, lon),
        zoom: 8,
        map: map,
        title: 'Vehicle No: '+v_id,
        icon: 'live.gif',
        optimized:false

    });
    markers[v_id] = marker;
    bounds.extend(new google.maps.LatLng(lat,lon));
   // map.setOptions({center:new google.maps.LatLng(lat,lon),zoom:8});
    map.fitBounds(bounds);
}

但问题是，有时我会得到距离道路 1.2 英寸的 GPS 坐标(可能是因为设备精度较低或信号失真等)我应该如何强制我的标记在路上自动调整？有什么办法，使用方向渲染或任何其他提示？？？请帮忙

Answer 1

在 2017 年，正确的做法是 Roads API Snap to Roads 服务。

您可以阅读有关此网络服务的信息

https://developers.google.com/maps/documentation/roads/snap

The Google Maps Roads API takes up to 100 GPS points collected along a route, and returns a similar set of data, with the points snapped to the most likely roads the vehicle was traveling along. Optionally, you can request that the points be interpolated, resulting in a path that smoothly follows the geometry of the road.