On a topographic map what do hachures indicate?

Question

On a topographic map what do hachures indicate?

Answer 1

Hachures are fine lines generally drawn in the direction of steepest topographic slope (gradient). These lines represent the slope of the land—the more gentle the slope, the fewer the lines —  thicker hachures indicate steeper slopes — and the absence of lines indicates flat terrain.

have been in use for a couple of hundred years - involves shading.

Answer 2

depressions :)