A system for conveying location of an object by varying a characteristic such as size, color, or intensity of an icon located in a two dimensional display. In the illustrative embodiment, the invention represents aircraft altitude by the size of an icon. Each aircraft position and heading is plotted as location and orientation of the icon in two-dimensional space, the axes of which represent latitude and longitude. The size of the icon is selected from a limited number of discriminably different sizes to represent the aircraft altitude. Each size represents a distinct altitude range.