在Openlayers中保持多边形大小不变

var map = new ol.Map({
  target: 'map',
  layers: [
    new ol.layer.Tile({
      source: new ol.source.OSM()
    })
  ],
  view: new ol.View({
    center: ol.proj.fromLonLat([0, 0]),
    zoom: 10
  })
});

var polygonFeature = new ol.Feature({
  geometry: new ol.geom.Polygon([[
    [0, 0],
    [1000, 0],
    [1000, 1000],
    [0, 1000],
    [0, 0]
  ]])
});

var vectorLayer = new ol.layer.Vector({
  source: new ol.source.Vector({
    features: [polygonFeature]
  })
});

map.addLayer(vectorLayer);

var scaleLineControl = new ol.control.ScaleLine({
  units: 'metric',
  minWidth: 100
});

map.addControl(scaleLineControl);