设置KML图层透明度

Question

有没有办法在添加kml图层时设置透明度？我正在添加一个你无法看到的kml层到下面的街道。有没有办法实现这一目标

 var map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions);

  var ctaLayer = new google.maps.KmlLayer({
    url: 'images/test3.kml'
  });

  var ctaLayer2 = new google.maps.KmlLayer({
    url: 'images/test.kml'
  });
  var ctaLayer3 = new google.maps.KmlLayer({
    url: 'images/kmztest2.kmz'
  });
  ctaLayer3.setMap(map);
  ctaLayer2.setMap(map);
  ctaLayer.setMap(map);
}

google.maps.event.addDomListener(window, 'load', initialize);

Answer 1

您无法修改KmlLayer中多边形的不透明度。你有三个选择（我能想到）：

1. 定义opacity in the KML

example，KML看起来像这样：

<Style
  id="Style1">
  <LineStyle><color>66000001</color><width>1</width></LineStyle>
  <PolyStyle>
    <color>00ff6633</color>  <!-- first 00 is opacity of zero -->
    <fill>1</fill>
    <outline>1</outline>
  </PolyStyle>
</Style>
<Placemark id="Opacity0">
  <name>Opacity 0</name>
  <visibility>1</visibility><open>0</open><styleUrl>#Style1</styleUrl>
  <Polygon><extrude>0</extrude><tessellate>1</tessellate><altitudeMode>clampToGround</altitudeMode>
    <outerBoundaryIs><LinearRing><coordinates>-116.365673309192,43.6628960911185 -116.365591334179,43.6560111958534 -116.364375539124,43.6559975333512 -116.364402864128,43.6483204644173 -116.359539767727,43.6483955662698 -116.359567092732,43.64422573708 -116.356452545151,43.6442223004997 -116.356329582632,43.6403188481927 -116.355482675135,43.6384234484285 -116.354444492608,43.6376550793648 -116.354198567569,43.6375697515905 -116.354198567569,43.6375560890883 -116.354348855093,43.6375355534256 -116.352818906307,43.6375834140927 -116.349636046216,43.6375697515905 -116.349677033722,43.6339155770838 -116.317438473925,43.6339155770838 -116.314392238855,43.6339600011706 -116.314187301323,43.6484194546938 -116.334391040727,43.6484843306243 -116.33440470323,43.6627594660968 -116.335292598233,43.6629438679665 -116.336767980829,43.6629097536206 -116.359348576516,43.6629985179752 -116.360673587769,43.6628994438797 116.365673309192,43.6628960911185</coordinates>

 </LinearRing></outerBoundaryIs></Polygon>
 </Placemark>

2. 将KML导入FusionTables，并使用FusionTablesLayer (which allows you to change the opacity of polygons) （不再有用，因为FusionTables将于2019年12月3日关闭/关闭）
3. 如果KML不是太复杂，请使用第三方解析器（geoxml3或geoxml-v3，它将解析KML并将其渲染为本机Google Maps Javascript API v3对象（允许您修改不透明度）。

Answer 2

由于Google Maps API将KML添加为DOM中的图像，您可以通过在<img>属性中搜索包含"kml"的src元素来使用CSS更改其不透明度：

#map img[src*='kml'] {
    opacity: .5;
}

此外，您可以使用jQuery实现此目的：

jQuery("#map").find("img[src*='kml']").css("opacity","0.5");

但请记住，当用户缩小或移动地图时，将加载新的KML图像，因此您必须再次调用该jQuery函数。

Answer 3

此解决方案并不完美，因为它在更改缩放级别时会引起轻微闪烁，但有些人可能会觉得这很有用：

google.maps.event.addListener(map, 'tilesloaded', function() {
            $("#map").find("img").css("opacity","0.5");
});