No. A spur is a promontory or secondary summit, a high point not a low point.
Depression
enzyme, impetus, reactant, spur, stimulant
obviously depression
hollow, hole, depression, dip, cavity, caldera
recession, slump, crash, panic; stagnation
despair, misery, sadness, the blues, melancholy, unhappiness, despondency
You're looking for a synonym for projection. (:Those would be extension, protuberance, spur, forecast, or out thrust.
That is the correct spelling of "topographical" (on an elevation map).
a concavity or depression - (informal) an attractive person
Topographical mapping software is part of the bundle.
A Topographical Dictionary of Ancient Rome was created in 1929.
Spur