An overlay showing population can be placed on top of the map.

可以在地图上加一层显示人口的透明膜。

《牛津词典》

This way you can query the database, directly producing XML, and use XSLT to transform the returned data directly into KML that you can overlay on a map.

采用该方法，您可以查询数据库，直接生成xml，并使用XSLT将返回的数据直接转换为可以在地图上覆盖的KML。

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Once the marker is added to the map as an overlay, the drawLine function is called.

将这个标记作为叠加层添加到地图上之后，调用drawLine函数。

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The navigation system can display Google Earth imagery beneath the map overlay, which is sure to keep passengers entertained.

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Google Maps is following up last year's 8-bit maps overlay with an old-timey treasure map.

CNN: Heather Kelly,

Both systems utilize Clear Channel's Total Traffic Network1 service to provide an overlay of real-time traffic events and conditions on the navigation map and allow users to create routes (or re-route) to minimize traffic delays.

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