将地图标记添加到 Open Layers 6 [英] Adding map markers to Open Layers 6

问题描述

我的问题很简单:如何在特定的经纬度添加标记?

处理开放图层 示例页面 我创建了一张新地图用记号笔.

我使用 new ol.Feature 添加了标记，但似乎无论我如何设置标记位置的坐标都不会改变.

请任何人就为什么地图标记未显示在正确位置提供建议?

const iconFeature = new ol.Feature({geometry: new ol.geom.Point([53, -2]),//这个标记不会移动.name: '某处',});const map = new ol.Map({目标:'地图'，层数:[新的 ol.layer.Tile({来源:新 ol.source.OSM(),}),新的 ol.layer.Vector({来源:新 ol.source.Vector({特点:[iconFeature]}),风格:新 ol.style.Style({图像:新 ol.style.Icon({锚点:[0.5, 46]，anchorXUnits: '分数',anchorYUnits: '像素',src: 'https://openlayers.org/en/latest/examples/data/icon.png'})})})],视图:新 ol.View({中心:ol.proj.fromLonLat([53,-2]),变焦:6})});

.map {宽度:100%；高度:400px；}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script><script src="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.1.1/build/ol.js"></script><div id="map" class="map"><div id="popup"></div>

解决方案

您可以使用 ol.proj.fromLonLat 将 EPSG:4326 转换为 EPSG:3857，对于既具有特征又使地图居中.一般来说，您必须这样做，因为默认投影是 EPSG:3857.

对于图标:

const iconFeature = new ol.Feature({几何:新 ol.geom.Point(ol.proj.fromLonLat([-2, 53])),name: '靠近诺丁汉',});

使视图/地图在同一位置居中:

view: new ol.View({中心:ol.proj.fromLonLat([-2, 53]),变焦:6})

工作代码片段:

const iconFeature = new ol.Feature({几何:新 ol.geom.Point(ol.proj.fromLonLat([-2, 53])),name: '靠近诺丁汉',});const map = new ol.Map({目标:'地图'，层数:[新的 ol.layer.Tile({来源:新的 ol.source.OSM()，}),新的 ol.layer.Vector({来源:新 ol.source.Vector({特点:[iconFeature]}),风格:新 ol.style.Style({图像:新 ol.style.Icon({锚点:[0.5, 46]，anchorXUnits: '分数',anchorYUnits: '像素',src: 'https://openlayers.org/en/latest/examples/data/icon.png'})})})],视图:新 ol.View({中心:ol.proj.fromLonLat([-2, 53]),变焦:6})});

html, body {宽度:100%；高度:100%；填充:0px；边距:0px；}.地图 {宽度:100%；高度:100%；}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script><script src="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.1.1/build/ol.js"></script><div id="map" class="map"><div id="popup"></div>

My question is simple: How do you add a marker at a specific longitude and latitude?

Working through the open layers example page I have created a new map with a marker.

I added the marker using the new ol.Feature but it seems no matter what I set the coordinates to the marker position will not change.

Please can anyone offer advice on why the map marker is not showing in the correct position?

const iconFeature = new ol.Feature({
  geometry: new ol.geom.Point([53, -2]), //This marker will not move.
  name: 'Somewhere',
});

const map = new ol.Map({
  target: 'map',
  layers: [
    new ol.layer.Tile({
      source: new ol.source.OSM(),
    }),
    new ol.layer.Vector({
      source: new ol.source.Vector({
        features: [iconFeature]
      }),
      style: new ol.style.Style({
        image: new ol.style.Icon({
          anchor: [0.5, 46],
          anchorXUnits: 'fraction',
          anchorYUnits: 'pixels',
          src: 'https://openlayers.org/en/latest/examples/data/icon.png'
        })
      })
    })
  ],
  view: new ol.View({
    center: ol.proj.fromLonLat([53,-2]),
    zoom: 6
  })
});

.map {
  width: 100%;
  height: 400px;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.1.1/build/ol.js"></script>

<div id="map" class="map">
  <div id="popup"></div>
</div>

解决方案

You can use ol.proj.fromLonLat to transform EPSG:4326 to EPSG:3857, for both features and centering the map. In general you have to do that as the default projection is EPSG:3857.

for icons:

const iconFeature = new ol.Feature({
  geometry: new ol.geom.Point(ol.proj.fromLonLat([-2, 53])),
  name: 'Somewhere near Nottingham',
});

to center the view/map at the same place:

view: new ol.View({
  center: ol.proj.fromLonLat([-2, 53]),
  zoom: 6
})

working code snippet:

const iconFeature = new ol.Feature({
  geometry: new ol.geom.Point(ol.proj.fromLonLat([-2, 53])),
  name: 'Somewhere near Nottingham',
});

const map = new ol.Map({
  target: 'map',
  layers: [
    new ol.layer.Tile({
      source: new ol.source.OSM(),
    }),
    new ol.layer.Vector({
      source: new ol.source.Vector({
        features: [iconFeature]
      }),
      style: new ol.style.Style({
        image: new ol.style.Icon({
          anchor: [0.5, 46],
          anchorXUnits: 'fraction',
          anchorYUnits: 'pixels',
          src: 'https://openlayers.org/en/latest/examples/data/icon.png'
        })
      })
    })
  ],
  view: new ol.View({
    center: ol.proj.fromLonLat([-2, 53]),
    zoom: 6
  })
});

html, body {
  width: 100%;
  height: 100%;
  padding: 0px;
  margin: 0px;
}
.map {
  width: 100%;
  height: 100%;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io@master/en/v6.1.1/build/ol.js"></script>

<div id="map" class="map">
  <div id="popup"></div>
</div>

这篇关于将地图标记添加到 Open Layers 6的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！