MAP STORAGE FOR NAVIGATION SYSTEMS

When preparing a representation of map display information for use by a navigation device, a set of source map data (600) is subject to a similarity analysis step (601) to try to identify elements in the source map data (600) that are similar in terms of their shape and/or their appearance when displayed. A classification and transformation parameter generation step (602) then classifies elements in the map into groups of similar elements as determined by the similarity analysis (601) and also determines the parameters and conditions under which the identified map elements can be considered to be similar. This is then used to generate a map database that includes a library of predefined map display elements having parametrable aspects, which map display elements can then be used to construct a desired map for display.