- The two hemispheres differ in elevation by 1 to 3 km.
There's that much variation within the highlands, so what does this sentence mean? If it's about the bimodal distribution of elevations, the difference between the maxima appears to be ~5 km. All of the great peaks (except Arsia) are in the north, and the lowest region of all (Hellas) is in the south! —Tamfang (talk) 04:54, 14 September 2010 (UTC)
I agree. I'm currently working on the Geology of Mars article, which will include a brief section on the dichotomy. I think this article should say something like "the two hemispheres differ in mean elevation by..." Also, according to Watters, T. et al. (2007), the difference in mean elevation between hemispheres is actually 2.5 to 6 km. I think the author here used pre-MOLA estimates. For example, Cattermole (2000), p. 19, also used the 1-3 km range. BTW: this article should also mention that elevations are relative to reference ellipsoid based on gravity etc., and that the dichotomy is well illustrated by bimodal distribution in hypsometry. On the plus side the references for this article seem very good. Schaffman (talk) 12:09, 14 September 2010 (UTC)