ground mark for aerial photography

例句：

1. 1.The ancient city is a famous landmark in the region.
   这个古老的城市是该地区的一个著名地标。
2. 2. This monument serves as a historical ground mark for tourists.
   这座纪念碑是游客的历史地标。
3. 3. The map has several ground marks that indicate the locations of key landmarks.
   这张地图上有多个地标，指示着关键地标的地点。