In a 2D polar coordinate system points can be described with coordinates. Another way of defining a point in a plane is by using polar coordinates. This is the distance d from the origin to the point concerned and the angle α between a fixed (or zero) direction and the direction to the point. The angle α is called azimuth or bearing and is measured in a clockwise direction. It is given in angular units while the distance d is expressed in length units.
Distance also plays a role in computations on networks, comprising a different set of analytical functions in GISs. Here, the network may consist of roads, public transport routes, high-voltage power lines, or other forms of transportation infrastructure. Analysis of networks may entail shortest path computations (in terms of distance or travel time) between two points in a network for routing purposes. Other forms are to find all points reachable within a given distance or duration from a start point for allocation purposes, or determination of the capacity of the network for transportation between an indicated source location and sink location.
In raster images, the distance function applied is the Pythagorean distance between the cell centres. The distance from a non-target cell to the target is the minimal distance one can find between that non-target cell and any target cell.