OpenLayers 3：並非LineString中的所有行都在渲染

Question

我試圖使用與在地圖上繪制標記集合相同的坐標繪制lineString。 繪制標記，然后將lineString繪制成與標記連接的狀態，lineString使用與標記相同的坐標。

我遇到了奇怪的問題，有時會畫所有的線，有時只會畫一條線。 但通常會缺少一兩行。 當我在lineString上運行getCoordinates（）時，它會返回與標記位置相同的所有坐標，但未繪制某些線。

一些代碼：

// location data, contains x/y coords
var locs = JSON.parse(loc_data);  
var lineCoords = [];
var lat;
var lng;

// loop through loc data and output the markers 
for (var key in locs) {
    if (locs.hasOwnProperty(key)) {

        lat = locs[key].lat;
        lng = locs[key].lng;

        // store the coords in an array to be used for the lineString
        lineCoords.push([lat,lng]);

        // create marker and add to map
        var iconFeature = new ol.Feature({
            geometry: new ol.geom.Point([lat, lng]),
        });            

        var vectorSource = new ol.source.Vector({
            features: [iconFeature]
        });

        var vectorLayer = new ol.layer.Vector({
            source: vectorSource
        });

        map.addLayer(vectorLayer);                                               
    }                
}


// draw lineString using coordinates in lineCoords array
var line = new ol.geom.LineString(lineCoords);

var layerLines = new ol.layer.Vector({
    source: new ol.source.Vector({
        features: [new ol.Feature({
                geometry: line,
                name: 'Line'
            })]
    }),
});

map.addLayer(layerLines);

上面的代碼似乎很合乎邏輯，我看不出它可能在哪里出現問題，就像說的那樣，有時繪制所有線條，有時僅繪制一行。

誰能對此有所啟發？

Answer 1

嘗試更改：

// location data, contains x/y coords
var 
    locs = JSON.parse(loc_data),
    lineCoords = [], features = [],
    lat, lng, iconFeature
;

// loop through loc data and output the markers 
for (var key in locs) {
    if (locs.hasOwnProperty(key)) {

        lat = locs[key].lat; //is this already EPSG:3857 ?
        lng = locs[key].lng;

        // store the coords in an array to be used for the lineString
        lineCoords.push([lng, lat]);

        // create marker and add to map
        iconFeature = new ol.Feature({
            geometry: new ol.geom.Point([lng, lat]),
        });
        features.push(iconFeature);
    }                
}

var
    vectorSource = new ol.source.Vector({
        features: features //your LineString could also be included here
    }),
    vectorLayer = new ol.layer.Vector({
        source: vectorSource
    }),
    // draw lineString using coordinates in lineCoords array
    line = new ol.geom.LineString(lineCoords),
    layerLines = new ol.layer.Vector({
        source: new ol.source.Vector({
            features: [new ol.Feature({
                geometry: line,
                name: 'Line'
            })]
        })
    })
;
map.addLayer(vectorLayer);
map.addLayer(layerLines);