【问题标题】:How to change openlayer 6 view center?如何更改openlayer 6视图中心?
【发布时间】:2020-09-09 11:46:46
【问题描述】:

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8"/>
    <link rel="stylesheet" href="https://openlayers.org/en/v6.4.3/css/ol.css" type="text/css">
    <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
    <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
    <script src="https://openlayers.org/en/v6.4.3/build/ol.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.6.1/proj4.js"></script>
    <style>
      html, body, .map {
        margin: 0;
        padding: 0;
        width: 99%;
        height: 95%;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div> 
<div id="mouse-position"></div>

    <script>

proj4.defs("EPSG:32643","+proj=utm +zone=43 +datum=WGS84 +units=m +no_defs");
ol.proj.proj4.register(proj4);
ol.proj.get("EPSG:32643").setExtent([291627, 904686, 958569, 1426831]);

var projection = new ol.proj.Projection({
  code: 'EPSG:32643',
  extent: [291627,904686,958569,1426831],
});
  
var mousePositionControl = new ol.control.MousePosition({
  coordinateFormat: ol.coordinate.createStringXY(4),
  projection: projection,//'EPSG:32643',
  // comment the following two lines to have the mouse position
  // be placed within the map.
  className: 'custom-mouse-position',
  target: document.getElementById('mouse-position'),
  undefinedHTML: '&nbsp;',
});
var scaleLine = new ol.control.ScaleLine({
units: 'metric',
});
 
var map = new ol.Map({
  controls: ol.control.defaults().extend([mousePositionControl,scaleLine]),
  target: 'map',
  layers: [    
    new ol.layer.Tile({
            source: new ol.source.XYZ({
                url: "http://103.10.168.74:8081/tms/1.0.0/district/distgrid" + "/{z}/{x}/{-y}.png",
                projection:projection,
                tileGrid: ol.tilegrid.createXYZ({
                  extent: [291627, 904686, 958569, 1426831],
                  maxResolution: 2605.2421875,
                  tileSize: [256, 256],
                  maxZoom: 10,
                }),
          }),
    }),
    new ol.layer.Vector({
        source: new ol.source.Vector({  
            features: [new ol.Feature({
                  geometry: new ol.geom.Point([614971.473,1218630.894]),
            })],
        }),
        renderBuffer: 200,
        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'
            })
        })
  }),
  new ol.layer.Vector({
     source: new ol.source.Vector({
         features: [
             new ol.Feature({
        geometry: new ol.geom.Point([716446.977962414,942574.737260181]),

             })
         ]
     })
  }) 
  ],
  view: new ol.View({
    projection: projection, 
    units:"metric",
    zoom:1,
    maxResolution:2605.2421875,
    center:[654496.136597752,1155181.26900064],
    numZoomLevels:13,        
    constrainOnlyCenter: true,
    maxZoom:10,
    minZoom:1,
  })
});
  
mousePositionControl.setProjection(projection);
   </script>
  </body>
</html>

我在 ol6 (mapnik & mapproxy) 中添加了一个矢量图层和一个平铺层。但是投影存在问题,两层相距甚远。我的代码是

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8"/>
    <link rel="stylesheet" href="https://openlayers.org/en/v6.4.3/css/ol.css" type="text/css">
    <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
    <script src="https://openlayers.org/en/v6.4.3/build/ol.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.6.1/proj4.js"></script>
    <style>
      html, body, .map {
        margin: 0;
        padding: 0;
        width: 99%;
        height: 99%;
    border:1px solid #ccc;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <script>

proj4.defs("EPSG:32643","+proj=utm +zone=43 +datum=WGS84 +units=m +no_defs");
ol.proj.proj4.register(proj4);

 //-----vector lyr-----
var london = new ol.Feature({
  geometry: new ol.geom.Point(ol.proj.fromLonLat([8.5149092,76.9527723])),
}); 
london.setStyle(
  new ol.style.Style({
    image: new  ol.style.Icon({
      color: '#4271AE',
      crossOrigin: 'anonymous',
      src: 'https://openlayers.org/en/latest/examples/data/icon.png',
      scale: 0.5,
    }),
  })
);
var vectorSource = new ol.source.Vector({
  features: [london],
  projection: "EPSG:32643",
});

var vectorLayer = new ol.layer.Vector({
  source: vectorSource,
});
  //-----vector lyr-----
         
var map = new ol.Map({
  target: 'map',
  layers: [    
    new ol.layer.Tile({
            source: new ol.source.XYZ({
           url: "http://127.0.01:8080/tms/1.0.0/district/distgrid" + "/{z}/{x}/{-y}.png",
           projection: "EPSG:32643",
       }),
     }), 
     vectorLayer    
  ],
  view: new ol.View({
    projection: "EPSG:32643",
    units:"m",
    zoom:1,
    maxZoom:10,
    minZoom:1,
    center:[8.5149092,76.9527723],

  })
});

map.getView().fit(vectorSource.getExtent());
map.getView().setZoom(map.getView().getZoom() - 10);

//map.getView().setCenter(ol.proj.transform([8.5149092,76.9527723], 'EPSG:32643', 'EPSG:32643'));

    </script>
  </body>
</html>

我试图改变地图的中心,但它不起作用。我的地图以“米”为单位,UTM 43N 和 EPSG:32643。 我在 ol2 中使用的范围是 291627,904686,958569,1426831 & maxResolution:2605.2421875。我也尝试将 tileGrid 添加到 tile 图层,但它也不起作用。

var resolutions = [
    2605.2421875,
    // don't know how to find resolution
];
tileGrid: new ol.tilegrid.TileGrid({
      extent: [291627,904686,958569,1426831],
      resolutions: resolutions,
      tileSize: [256, 256],
}),

【问题讨论】:

    标签: openlayers openlayers-3 tile openlayers-6


    【解决方案1】:

    您的几何图形和中心需要与视图处于同一投影中

      geometry: new ol.geom.Point(ol.proj.fromLonLat([8.5149092, 76.9527723], "EPSG:32643")),
    
    
      center: ol.proj.fromLonLat([8.5149092, 76.9527723], "EPSG:32643"),
    

    你不需要在vectorSource上设置投影。

    如果您的平铺网格具有 0 到 10 的缩放级别 tileGrid 可以使用

    tileGrid: ol.tilegrid.createXYZ({
          extent: [291627, 904686, 958569, 1426831],
          maxResolution: 2605.2421875,
          tileSize: [256, 256],
          maxZoom: 10,
    }), 
    

    您可能还想设置投影范围以匹配

    ol.proj.get("EPSG:32643").setExtent([291627, 904686, 958569, 1426831]);
    

    对于原点位于瓦片网格左下角的 TMS 源,OpenLayers 期望 maxResolution 与网格范围的高度匹配,但在您的情况下,它与宽度匹配。解决此问题的一种方法是在高度等于宽度的情况下使用更大的范围。添加 OSM 层表明它现在位于正确的位置。

    <!DOCTYPE html>
    <html lang="en">
    <head>
    <meta charset="utf-8"/>
        <link rel="stylesheet" href="https://openlayers.org/en/v6.4.3/css/ol.css" type="text/css">
        <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
        <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
        <script src="https://openlayers.org/en/v6.4.3/build/ol.js"></script>
        <script src="https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.6.1/proj4.js"></script>
        <style>
          html, body, .map {
            margin: 0;
            padding: 0;
            width: 99%;
            height: 95%;
          }
        </style>
      </head>
      <body>
        <div id="map" class="map"></div> 
    <div id="mouse-position"></div>
    
        <script>
    
    proj4.defs("EPSG:32643","+proj=utm +zone=43 +datum=WGS84 +units=m +no_defs");
    ol.proj.proj4.register(proj4);
    ol.proj.get("EPSG:32643").setExtent([291627, 904686, 958569, 1426831]);
    
    var projection = new ol.proj.Projection({
      code: 'EPSG:32643',
      extent: [291627,904686,958569,1426831],
    });
      
    var mousePositionControl = new ol.control.MousePosition({
      coordinateFormat: ol.coordinate.createStringXY(4),
      projection: projection,//'EPSG:32643',
      // comment the following two lines to have the mouse position
      // be placed within the map.
      className: 'custom-mouse-position',
      target: document.getElementById('mouse-position'),
      undefinedHTML: '&nbsp;',
    });
    var scaleLine = new ol.control.ScaleLine({
    units: 'metric',
    });
     
    var extent = [291627, 904686, 958569, 1426831];
    var fullExtent = [extent[0], extent[1], extent[2], extent[1] + extent[2] - extent[0]];
    
    var map = new ol.Map({
      controls: ol.control.defaults().extend([mousePositionControl,scaleLine]),
      target: 'map',
      layers: [   
         new ol.layer.Tile({
                source: new ol.source.XYZ({
                    url: "http://103.10.168.74:8081/tms/1.0.0/district/distgrid" + "/{z}/{x}/{-y}.png",
                    projection:projection,
                    tileGrid: ol.tilegrid.createXYZ({
                      extent: fullExtent,
                      maxResolution: 2605.2421875,
                      tileSize: [256, 256],
                      maxZoom: 10,
                    }),
              }),
        }),
        new ol.layer.Tile({
          source: new ol.source.OSM(),
          opacity: 0.5,
        }),
        new ol.layer.Vector({
            source: new ol.source.Vector({  
                features: [new ol.Feature({
                      geometry: new ol.geom.Point([614971.473,1218630.894]),
                })],
            }),
            renderBuffer: 200,
            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'
                })
            })
      }),
      new ol.layer.Vector({
         source: new ol.source.Vector({
             features: [
                 new ol.Feature({
            geometry: new ol.geom.Point([716446.977962414,942574.737260181]),
    
                 })
             ]
         })
      }) 
      ],
      view: new ol.View({
        projection: projection, 
        units:"metric",
        zoom:1,
        maxResolution:2605.2421875,
        center:[654496.136597752,1155181.26900064],
        numZoomLevels:13,        
        constrainOnlyCenter: true,
        maxZoom:10,
        minZoom:1,
      })
    });
      
    mousePositionControl.setProjection(projection);
       </script>
      </body>
    </html>

    【讨论】:

    • 我在上面添加了一个工作代码,因为我已经将矢量图层点从十进制度数更改为米,并添加了 tileGrid 和投影,就像你上面说的那样。但是地图仍然没有正确渲染。
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