Originally Posted by algorithms

Perhaps folks should take a look at the remote sensing work used in terrestrial archaeology for some ideas here. Both satellite imagery and aerial photography are used by archaeologists in their search for evidence of past human settlements. Here is an interesting piece on the subject:

GIS TECHNIQUES, REMOTE SENSING AND MULTIVARIATE MODELS IN ASSESSING ARCHAEOLOGICAL RESOURCES

What I gather from looking at this and other materials on the subject is that you can't simply rely upon the shape of an object in order to identify it as a potential archaeological resource. There are other important variables that must be considered in order to narrow down the candidates. That's because symmetry and regular geometric shape is a common occurrence in natural geology. In fact, these materials suggest that its an entirely useless pursuit of time to simply peruse satellite images in search of archaeology. One must know something about the geology and geophysical history of a location in order to know where to look and what to look for.