Even in their survey manuals they say that all instruments use a straight reference plane...in other words they're all designed to measure a flat plane b/c they ARE on a flat plane.

@GordonSBrooks @keigh_see @MichaelSteidel @doctorbuttons @surfpurzel @sly_sparkane @garethkett @maxsec @RealAceFox1 @GEIST_VIEW @earthisaglobe @100KryptoKeyz @laughchem @Mctoon27 @LaikaAndYuri @ReillyOToole1 @ASongless @dimetu26 yeah...level. Topography is the terrain on the surface of the earth which is why when survey manuals state that all elevation measurements are taken FROM a level surface, the elevations are the slopes, dips, rises from earth's surface. Here's an example:

@maxsec @keigh_see @RealAceFox1 @ReillyOToole1 @Mctoon27 @ASongless "Appears" flat isn't the same as being flat! When something measures flat, it's flat in physicality! Survey manuals make it clear that ALL measurements are taken FROM a flat plane, i.e. ground of the flat earth. For instance, you can't measure water levels from a mirage..can you?