The Distance and Connectivity function can be used to calculate movement times, often incorporating different impedance factors. Travel times may be as diverse as those for forest fires (using wind speed, direction, fuel supply, recent rainfall, etc.), emergency response vehicles (using traffic density and speed, number of necessary stop, etc.), or wilderness hikers (using grade of slope, type of trail, etc.).

Features modifying distance are cartographically represented by 'barriers' located in the space being measured. Two types of barriers that affect the ability to move are absolute and relative barriers.

Absolute barriers

completely restrict movement, unless an alternate path around the barrier exists.

Relative barriers

are passable only with a cost that may be equated with an increase in physical distance and/or energy expenditure. In such applications distance is best described in rates which vary over time and space -- movement expressed in travel time and potential cost and energy consumed.

Travel Time without Barriers:
The further the line from the starting point, the longer the travel time.

Travel Time with Relative Barriers:
The greater the slope, the more difficult the movement, the longer the travel time.