If you use the ThereClient’s EnvironmentVariableEditor to set the value of the trendSec variable to 1, the ThereClient will begin to paint the areas of terrain belonging to each sector using a flat colour rather than the “natural” colours for the terrain in that area. This allows you to see very clearly where the boundaries between sectors lie, at least at ground level.
Note that there will be a period during which the new colours gradually replace the old ones, or during which the trendSec painted colours persist after you return trendSec to 0 in order to remove the effect.
The colours trendSec shows for sectors have no significance. They are chosen by an algorithm in the ThereClient that simply maps each sector number to a (hopefully) different colour. The algorithm was changed in V2.0 of There because sectors numbered above 60 or so were all coming out with very similar or identical colours. For example, in V1 of There many parts of Motu Motu had very similar colours.