Different projections will be better for an accurate representation of one or more of these properties so that careful consideration should be given to the purpose to which the data will be put. For example, if the resulting data will be used for aircraft navigation, a projection that minimally distorts distance and direction along the principal axis of travel should be used. Figure 2 illustrates how the map plane can be formed into a variety of shapes, like a cylinder wrapped around the globe or a cone placed on the globe. This is clearly apparent on most world maps, which are typically done in the Mercator projection. On these maps, lands in the more southern or northern regions, such as Greenland, will appear much larger than they actually are.
Scale is another important aspect of geographic information.
Scale is typically represented as a ratio between a unit of distance on the map and its equivalent real-world distance. The scale at which geographic information is depicted and captured has a profound effect on the resolution or accuracy that can be achieved. The resolution of a map is the accuracy with which the location and shape of map features can be depicted for a given map scale. These minimum mapping units are usually incorporated into a set of rules for map construction. Factors relating to map scale, quality of source materials and field methods used to document the location of such features, map resolution, map maker, drafting skill, and the size of the instrument used to draw or render the map will all influence how accurately points and lines are placed on the map.