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我正在從Google地圖項目中進行工作，在那裏我使用從數據庫讀取的標記（drawMarkers函數）填充Google地圖。隨着谷歌地圖發現你的當前位置，並保持刷新它每隔幾秒鐘，以保持跟蹤你在地圖上。我的問題是，有一個var最接近這也是我正在使用的函數也找到最接近的標記，然後從那裏創建方向到當前位置。我不知道如何找到最接近的標記，所以我從堆棧溢出的另一個問題中借用了代碼，並試圖將其應用於此項目。我需要幫助讓我最親近的功能找到最接近的標記，然後讓它目的地的方向服務在谷歌地圖API中使用方向服務
$ionicSideMenuDelegate.canDragContent(false);
$scope.getTourMarkers = function() {
tourmarkers.getTourMarkers().success(function (data) {
$scope.tourmarkers = data;
console.log($scope.tourmarkers);
drawMarkers();
});
};
var drawMarkers = function() {
var markers;
var content;
var infoWindow;
for (var i = 0; i < $scope.tourmarkers.length; i++) {
content = '<h2>' + $scope.tourmarkers[i].title + '</h2>' +
'<br />' +
'<p>' +
'</p>';
infoWindow = new google.maps.InfoWindow({
content: content
});
var point = new google.maps.LatLng($scope.tourmarkers[i].lat, $scope.tourmarkers[i].lon);
markers = new google.maps.Marker({
label: "S",
animation: google.maps.Animation.DROP,
position: point,
map: map,
info: content
});
//SCOPE: 'this' refers to the current 'markers' object, we pass in the info and marker
google.maps.event.addListener(markers, 'click', function() {
infoWindow.setContent(this.info);
infoWindow.open(map, this);
});
}
};
var myLatlng = new google.maps.LatLng(38.5602, -121.4241);
var NAPA_HALL_LAT_LNG = new google.maps.LatLng(38.553801, -121.4212745); // just created this marker for testing purposes
var mapOptions = {
center: myLatlng,
zoom: 18,
mapTypeId: google.maps.MapTypeId.ROADMAP,
zoomControl: true,
disableDefaultUI: true
};
var map = new google.maps.Map(document.getElementById("map"), mapOptions);
var marker = new google.maps.Marker({
position: myLatlng,
map: map,
title: 'SAC STATE'
});
var dest = new google.maps.Marker({
position: NAPA_HALL_LAT_LNG,
map: map,
title: 'NAPA HALL'
});
///////////////////Directions Display//////////////////////
var directionsDisplay = new google.maps.DirectionsRenderer;
var directionsService = new google.maps.DirectionsService;
//////////////////////////////////////////////////////////////////////////////////////////
//Goal of this function is to find closest marker to current location
//then to create directions to that marker.
//should be refreshed everytime in the onSuccess function
var closest = function (directionsService, directionsDisplay, marker, dest) {
var event;
function rad(x) {return x*Math.PI/180;}
function find_closest_marker(event) {
var lat = event.latLng.lat();
var lng = event.latLng.lng();
var R = 6371; // radius of earth in km
var distances = [];
var shortest = -1;
for(i=0;i < $scope.tourmarkers.length; i++) {
content = '<h2>' + $scope.tourmarkers[i].title + '</h2>' +
'<br />' +
'<p>' +
'</p>';
infoWindow = new google.maps.InfoWindow({
var mlat = $scope.tourmarkers[i].position.lat();
var mlng = $scope.tourmarkers[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 (shortest == -1 || d < distances[shortest]) {
shortest = i;
}
}
alert(map.markers[shortest].title);
}
/////**directions feature should have the closest marker be the desitination//
directionsService.route({
origin: marker.position,
destination: dest.position, // i think the marker that should in here is shortest.
travelMode: google.maps.TravelMode.WALKING
}, function(response,status) {
if(status==google.maps.DirectionsStatus.OK) {
directionsDisplay.setDirections(response);
} else {
window.alert('Directions request failed due to ' + status);
}
});
};
//////////////////////////////////////////////////////////////////////////////////////////
var onSuccess = function (position) {
marker.setPosition(new google.maps.LatLng(position.coords.latitude, position.coords.longitude));
directionsDisplay.setMap(map);
dest.setPosition(new google.maps.LatLng(38.553801, -121.4212745));
//dest.setPosition((closest(marker, $scope.tourmarkers)).position); // if you can get this line to work without commenting it out then you're set
closest(directionsService,directionsDisplay, marker,dest);
$scope.map = map;
//$scope.map.panTo(new google.maps.LatLng(position.coords.latitude, position.coords.longitude));
};
function onError(error) {
alert('code: ' + error.code + '\n' +
'message: ' + error.message + '\n');
}
navigator.geolocation.watchPosition(onSuccess, onError, {
maximumAge: 3000,
timeout: 5000,
enableHighAccuracy: true
});
一切都在這個項目中工作正常，除了最接近的功能。但即使如此，我已經測試了方向服務，甚至也在工作。我只需要幫助，使方向服務中的目的地成爲與當前位置最接近的標記。