在谷歌地图或谷歌地球插件中惰性/需求加载KML？

发布于 2024-11-01 20:33:50 字数 1333 浏览 2 评论 0原文

一旦 Google 地图或 Google 地球插件实例启动，是否可以延迟加载 KML 文件？也许有一个“边界框”事件，我可以用它来排队所需的 KML 文件？

编辑 =>找到了答案：

找到了这个小窍门（http://code. google.com/apis/maps/documentation/javascript/events.html ）：

注意：如果您尝试检测改变视口，一定要使用特定的bounds_changed事件而不是组成部分zoom_changed 和 center_changed 事件。因为地图 API 会触发后面这些事件独立地， getBounds() 可能不会报告有用的结果，直到视口已发生权威性更改。如果你想在这样之后 getBounds() 一个事件，一定要听相反，bounds_changed 事件。

...这使我进入此页面上的“视口标记管理”：http ://code.google.com/apis/maps/articles/tooomymarkers.html#viewportmarkermanagement

建议这个基本想法：

  google.maps.event.addLisener(map, 'idle', showMarkers);

  function showMarkers() {
    var bounds = map.getBounds();

    // Call you server with ajax passing it the bounds

    // In the ajax callback delete the current markers and add new markers
  }

同样，对于 GEP，有这样的：

GEView.getViewportGlobeBounds()
返回一个完全的边界框包含地球上的区域目前可见。退回的盒子会比严格意义上的要大可见，如果有必要的话包括所有可见的内容。
返回一个对应的KmlLatLonBox 到当前的边界框视口或 null 如果没有部分地球仪可见

原文

Is it possible to lazy load KML files once a Google Map or Google Earth Plugin instance is started? Maybe there is there a "bounding box" event that I can use to queue needed KML files?

Edit => Found an answer:

Found this little tid-bit ( http://code.google.com/apis/maps/documentation/javascript/events.html ):

Note: If you are trying to detect a
change in the viewport, be sure to use
the specific bounds_changed event
rather than constituent zoom_changed
and center_changed events. Because the
Maps API fires these latter events
independently, getBounds() may not
report useful results until after the
viewport has authoritatively changed.
If you wish to getBounds() after such
an event, be sure to listen to the
bounds_changed event instead.

...which led me to "Viewport Marker Management" on this page: http://code.google.com/apis/maps/articles/toomanymarkers.html#viewportmarkermanagement

Suggesting this basic idea:

  google.maps.event.addLisener(map, 'idle', showMarkers);

  function showMarkers() {
    var bounds = map.getBounds();

    // Call you server with ajax passing it the bounds

    // In the ajax callback delete the current markers and add new markers
  }

Similarly, for GEP, there is this:

GEView.getViewportGlobeBounds()
Returns a bounding box that completely
contains the region of the globe that
is currently visible. The returned box
will be larger than what is strictly
visible, if that is necessary to
include everything that is visible.
Returns a KmlLatLonBox corresponding
to the bounding box of the current
viewport or null if no part of the
globe is visible