Interpreting Directions
In the context of CLTSE, Celestiodetic, and Map Projection SRF’s, the bound vector tuple {0,1,0} represents true north at any Reference Location! Bound vector tuple {0,0,1} represents Up.
A North Pointing Direction in the context of an CLTSE, Celestiodetic, or Map Projection SRF, when transformed to the Celestiocentric SRF, is unique! (except on the equator)
Map north equals true north plus Convergence of the Meridian.