This describes
what may possibly be the construction of a giant circle, roughly the size
of a crater nearby, using angles from hills in the area. The two large
craters in this photos may be artificial dams not actual craters. They are not
concave, and their floors seem the same as outside the craters. Also the crater
sides are not natural shapes, not round or elliptical and not in the shape from
a shock wave.
Here is the raw data photo
SP243304. You can download the original from here.
Copyright Malin Space Systems
There are many straight lines in this photo, and you should be able to see the arc like curve on the right side of the photo. The next picture is a rectified jpeg from NASA to give an overhead view.
