Table 3:

Resolution of the tiles used in our processing of the LALT direct altimetry data for orbit determination. Between 60°S and 60°N we use SLDEM2015, and outside of that the tiles are derived from the 512 ppd LOLA topographic grid. Polar caps are stereographic projections and hence have a unit of [m] instead of pixel-per-degree [ppd] in longitude. The equivalent resolution in [m] is given for the other grids. The ppd values are adjusted with latitude in order to obtain an approximately uniform grid (in meters). The resolution of the tiles is symmetric, so no indication of north (N) or south (S) latitude is given, except for the tile around the equator.

Area	Resolution [ppd, or m]
85° to poles	20 m
80°–85°	64 ppd (40–80 m)
70°–80°	128 ppd (40–80 m)
50°–70°	256 ppd (40–80 m)
50°S-50°N	512 ppd (40–60 m)