有人说“在月球上看到了长城”。其实宇航员奥尔德林和阿姆斯特朗并未看到,从地球看月球,有如椰子大小(视觉),在月球上看地球也只比椰子大3.4倍,可想而知,万里长城已远在人眼可分辨能力之外。利用航天遥感图像调查长城一直很吸引人,因为长城具有与铁路相似的超长线性特征,然而 Someone said “I saw the Great Wall on the moon.” In fact, astronauts Aldrin and Armstrong did not see, from the Earth to see the moon, like the size of coconut (vision), the Earth on Earth is only 3.4 times larger than coconut, you can imagine, the Great Wall is far away from people Eye beyond the ability to distinguish. The investigation of the Great Wall using aerial remote sensing images has always been attractive because the Great Wall has very long linear characteristics similar to railways,