In this beautiful VIS image, taken by the NASA - Mars Odyssey Orbiter on December, 5th, 2004, and during its 13.206th orbit around the Red Planet, we can see a small part of the Floor of Danielson Crater (a relatively large Impact Crater found in the Arabia Quadrangle of Mars and centered at 7,93° North Latitude and 7,11° West Longitude; it is roughly 66,7 Km - such as about 41,42 miles - in diameter).
Danielson Crater has (---> shows us) large Deposits of Material on its Floor that appear to be the final result of a strong Aeolian (with subsequent Erosional) Activity.
The Ridges and elongate Hills give us strong indications about the Dominant Winds' Direction. The Dark Material visible in this image is Sand, most likely Basaltic. The Sand, in time, has formed Dunes, but it can also can be (barely) seen filling small Valleys (or, maybe, tiny Cracks of the Floor) which are located toward the upper right (Dx) of the Main Dark Dune (that goes from the upper left - Sx - to the upper center of the frame).
Latitude (centered): 7,82772° North
Longitude (centered): 353,07100° East
This image (which is an Original Mars Odyssey Orbiter falsely colored and Map Projected frame published on the NASA - Planetary Photojournal with the ID n. PIA 20082) has been additionally processed, magnified to aid the visibility of the details, extra-contrast enhanced and sharpened, Gamma corrected and then re-colorized in Absolute Natural Colors (such as the colors that a normal human eye would actually perceive if someone were onboard the NASA - Mars Odyssey Orbiter and then looked down, towards the Surface of Mars), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.