Reconnaissance
Terrain-oriented route reconnaissance allows the commander to obtain information and capabilities about the adjacent terrain for maneuvering his forces, to include, any obstacles (minefields, barriers, steep ravines, marshy areas, or chemical, biological, radiological, and nuclear contamination) that may obstruct vehicle movement—on routes to, and in, his assigned area of operations. This requirement includes the size of trees and the density of forests due to their effects on vehicle movement. Route reconnaissance also allows the observation for fields of fire along the route and adjacent terrain. This information assists planners as a supplement to map information.

Zone: Zone reconnaissance focuses on obtaining detailed information before maneuvering their forces through particular, designated locations. It can be terrain-oriented, force-oriented, or both, as it acquire this information by reconnoitering within—and by maintaining surveillance over—routes, obstacles (to include nuclear-radiological, biological, and chemical contamination), and resources within an assigned location.
Also, force-oriented zone reconnaissance is assigned to gain detailed information about enemy forces within the zone, or when the enemy situation is vague by which the information concerning cross-country traffic-ability is desired. The reconnaissance provides the commander with a detailed picture of how the enemy has occupied the zone, enabling him to choose the appropriate course-of-action.
As the platoon conducts this type of zone reconnaissance, its emphasis is on determining the enemy's locations, strengths, and weaknesses. This is the most thorough and complete reconnaissance mission and therefore is very time-intensive.

Psychology: A tracker needs to pay close attention to both the environment and the psychology of their enemy. Knowledge of human psychology, sociology, and cultural backgrounds is necessary to know the actions of the enemy and what they will do or where they will go next. Chief of Scouts Frederick Russell Burnham commented on reconnaissance and scouts, saying:

It is imperative that a scout should know the history, tradition, religion, social customs, and superstitions of whatever country or people he is called on to work in or among. This is almost as necessary as to know the physical character of the country, its climate and products. Certain people will do certain things almost without fail. Certain other things, perfectly feasible, they will not do. There is no danger of knowing too much of the mental habits of an enemy. One should neither underestimate the enemy nor credit him with superhuman powers. Fear and courage are latent in every human being, though roused into activity by very diverse means.

Gallery: 

See also: Black reconnaissance
Exploration
Espionage
Intelligence, surveillance, target acquisition, and reconnaissance
List of reconnaissance units
Pathfinder (military) – airborne pathfinders
Spatial reconnaissance
Special reconnaissance (recon team)
Surveillance aircraft
U.S. military doctrine for reconnaissance

References: 

Further reading: 
Halsall, Christine, Women of Intelligence: Winning the Second World War with Air Photos, The History Press, 2012. ISBN 978-0-7524-6477-0.