Many ridge lines, groove lines and caldera segments have lengths which mark out the exact distance of a degree or fraction (1/2 or 1/4) of a degree. These can therefore be used by overhead spacecraft as calibration markers for distance from great altitudes since the markers have lengths ranging from 14.8 km to 118.5 km. These markers calibrate for several different degree systems and for fractions (1/50 or 1/100) of a radian, proving that these systems were used by the ancient Martian civilization in addition to the 360 degree system which we used on Planet Earth. Overwhelmingly, the most frequently used length of marker was that for one-half of a degree in the 360 degree system. This provides strong evidence for the extensive use of a 720 degree system.

The Martians used latitude degrees and radians for these calibration markers in a planetocentric coordinate system, since in such a system latitude degrees do not vary in length with an increase in distance from the equator. The planetocentric system treats the planet as a perfect sphere with a radius equal to the equatorial radius.

The calibration markers were found scattered around the planet. However, they occurred most frequently near the giant mountains of Elysium Mons, Olympus Mons and the Tharsis Montes. They seemed to be arranged along 2 major flight paths: a northerly one aligned with Elysium Mons and Olympus Mons, and a more southerly one aligned with Apollinaris Mons and the Tharsis Montes. Since the calibration markers could be used for spacecraft to determine altitude without breaking electromagnetic silence, one of their main purposes may have been to assist spacecraft as they were approaching landing sites. It is speculated that small spacecraft might have been used to enter biospheres within the major mountains.

Background material for this video can be found on my Brighteon channel:

https://www.brighteon.com/channel/epiphi