In UTM projection, distortion is small near central meridian, when you move away it increases. A
and B
are near central meridian in UTM Zone 8
. When you convert them to UTM Zone 10
, coordinates of A
and B
are calculated based on central meridian of UTM Zone 10
.
After convertiontransformation, points are still in the same location on earth, but far from central meridian of Zone 10
in comparison with Zone 8
's. Therefore, distortion of A-B
distance is bigger. This is nature of UTM.