Aligning the map with real life landscape features like roads or mountain ranges will also work. The sun has been used by mariners as a compass for centuries. The morning sun is eastward, at noon it can be found in the south, and later in the day it sets westward. Contour lines represent common landscape elevations above sea level. Contours close to each other represent steep terrain.
Contours spread far apart identify gentle to flat slopes.
Another common field instrument is an altimeter which measures elevation above sea level. It works on the basis of air pressure, which decreases with elevation gain.