我只想在某个地理定位半径内显示标记？ [英] I want to only show markers within a certain radius of geolocation?
问题描述
在我的页面上，当它加载时，它会获取您的位置并在您的位置设置标记，然后我希望它从我的数据库加载所有标记并将其设置在地图上，但我只想加载位于其中的标记1公里的位置。我试图设置它，但我遇到了一些麻烦。
因此，标记从数据库中加载，如下所示：
<？php while（$ stmt - > fetch（））{？>
var longi =<？php echo $ gLongitude;？>;
var lati =<？php echo $ gLatitude;？>;
var title =<？php echo $ gTitle;？>;
setMarker（lati，longi，title）;
<？php} $ stmt - >关（）; $ mysqli - >关闭（）;？>
然后setMarker函数调用如下所示：
函数setMarker（lati，longi，title）{
var latLongMarker = new google.maps.LatLng（lati，longi）;
marker = new google.maps.Marker（{
position：latLongMarker，
map：map，
draggable：false，
title：title
} ）;
arrMarkers.push（marker）;
}
这一切都可以正常工作，并将数据库中的所有标记加载到地图，但我怎么可能只加载距离我1公里的地图？我读了about computeDistanceBetween（），但我找不到一个拯救我生命的例子。
我最终找到了一种方法来完成这个任务，最终在这里处理起来更容易，更快速。未来：
<？php while（$ stmt - > fetch（））{？>
var longi =<？php echo $ gLongitude;？>;
var lati =<？php echo $ gLatitude;？>;
var title =<？php echo $ gTitle;？>;
var content ='巴士抵达：'+<？php echo $ gWeekdayDay;？>;
database.push（{latitude：lati，longitude：longi，markerTitle：title，content：content}）;
<？php} $ stmt - >关（）; $ mysqli - >关闭（）;？>
for（var i = 0; i< database.length; i ++）{
createMarker（database [i] .latitude，database [i] .longitude，database [i]。 markerTitle，initialLocation，
database [i] .content）;
函数createMarker（lati，longi，title，myPosition，content）{
var latLongMarker = new google.maps.LatLng（lati，longi）;
distanceCompare.push（{position：latLongMarker，markerTitle：title}）;
setMarker（myPosition，latLongMarker，title，content）;
函数setMarker（myPosition，latLongMarker，title，content）{
$ b $ distance = google.maps.geometry.spherical.computeDistanceBetween（latLongMarker，myPosition）;
console.log（''+ latLongMarker +'和原始位置'+ myPosition +'的距离等于'+距离';
updateResults（）;
if（distance< setDistance）{
addMarker（latLongMarker，title，content）;
stopsfound ++;
updateResults（）;
console.log（content）;
函数addMarker（位置，标题，内容）{
console.log（'正在添加标记'+内容）;
marker = new google.maps.Marker（{
position：position，
map：map，
title：title
}）;
bindInfoWindow（marker，content）;
markersArray.push（marker）;
您需要使用 Haversine formaula 。下面的代码使用这个公式使用 <强> PDO 。您将需要更改 $ mysqli 。
$ stmt = $ （弧度（θ））* cos（弧度（lat））* cos（弧度（lng） - 弧度（θ））+ sin（sinθ）弧度（？））* sin（弧度（lat））））AS距离距离mytable HAVING距离< 1 ORDER BY距离ASC LIMIT 0,20）;
//赋值参数
$ stmt-> bindParam（1，$ center_lat）; //坐标位置
$ stmt-> bindParam（2，$ center_lng）; //坐标位置
$ stmt-> bindParam（3，$ center_lat）;
此查询用于 DEMO
On my page, when it loads it gets your location and sets a marker on your spot, then I want it to load all markers from my database and set them on the map, but I only want to load markers that are within 1km of their location. I'm trying to set it up but I'm having a bit of trouble.
So the markers are loaded from the database like so:
<?php while($stmt -> fetch()) { ?>
var longi = "<?php echo $gLongitude; ?>";
var lati = "<?php echo $gLatitude; ?>";
var title = "<?php echo $gTitle; ?>";
setMarker(lati, longi, title);
<?php } $stmt -> close(); $mysqli -> close();?>
and then the setMarker function calls like this:
function setMarker(lati, longi, title) {
var latLongMarker = new google.maps.LatLng(lati,longi);
marker = new google.maps.Marker({
position: latLongMarker,
map: map,
draggable: false,
title: title
});
arrMarkers.push(marker);
}
That all works fine and dandy, and loads all the markers from the database onto the map but how might I load only ones that are 1km from me? I read about computeDistanceBetween() but I can't find an example to save my life. Thanks everybody in advance.
I ended up working out a way to do it that ended up being much easier and faster to process here you go for anybody looking for this in the future:
<?php while($stmt -> fetch()) { ?>
var longi = "<?php echo $gLongitude; ?>";
var lati = "<?php echo $gLatitude; ?>";
var title = "<?php echo $gTitle; ?>";
var content = 'Bus arrives at: ' + "<?php echo $gWeekdayDay; ?>";
database.push({latitude: lati, longitude: longi, markerTitle: title, content: content});
<?php } $stmt -> close(); $mysqli -> close();?>
for (var i = 0; i < database.length; i++) {
createMarker(database[i].latitude, database[i].longitude, database[i].markerTitle, initialLocation,
database[i].content);
}
function createMarker(lati, longi, title, myPosition, content) {
var latLongMarker = new google.maps.LatLng(lati, longi);
distanceCompare.push({position: latLongMarker, markerTitle: title});
setMarker(myPosition, latLongMarker, title, content);
}
function setMarker(myPosition, latLongMarker, title, content) {
distance = google.maps.geometry.spherical.computeDistanceBetween(latLongMarker, myPosition);
console.log('Distance of '+latLongMarker+ 'and original position' + myPosition + 'Is equal to '+distance);
updateResults();
if (distance < setDistance) {
addMarker(latLongMarker, title, content);
stopsfound++;
updateResults();
console.log(content);
}
}
function addMarker(position, title, content) {
console.log('Adding Marker ' + content);
marker = new google.maps.Marker({
position: position,
map: map,
title: title
});
bindInfoWindow(marker, content);
markersArray.push(marker);
}
You will need to use the Haversine formaula. The code below uses this formula using PDO. You will need change it for $mysqli.
$stmt = $dbh->prepare("SELECT name, lat, lng, (6372.8 * acos( cos( radians(?) ) * cos( radians( lat ) ) * cos( radians( lng ) - radians(?) ) + sin( radians(?) ) * sin( radians( lat ) ) ) ) AS distance FROM mytable HAVING distance < 1 ORDER BY distance ASC LIMIT 0 , 20");
// Assign parameters
$stmt->bindParam(1,$center_lat);//Coordinates of location
$stmt->bindParam(2,$center_lng);//Coordinates of location
$stmt->bindParam(3,$center_lat);
This query was used in this DEMO
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