Angular measurement in the DIN standard uses pointings to form angles, is it the same in the ISO standard?
I've never seen either of the standards in their entirety, but my strong impression is that they have somewhat different procedures for determining the same thing: the standard deviation of a horizontal direction that's the average of a pointing in one face (direct, Face 1, Face Left, etc) and a pointing in the other face (reverse, Face 2, Face Right, etc), and similarly for a zenith angle. I've always been suspicious of total station or theodolite manufacturers' specifications, which typically give a single ISO 17123 or DIN 18723 value, in regard to whether that value is supposed to be for just horizontal directions or also for zenith angles. I can't recall ever seeing a spec sheet that explicitly labels standard deviations for both horizontal directions and zenith angles (even if the numbers happen to be the same). Some of my impressions of these standards come from the book "Precision Surveying" by John Olusegun Ogundare, 2016, pages 122 ?? 130 in particular.