Abstract: Disclosed is a method for displaying a topology having topological features on a display. The method includes dividing the topological region into tessellations. An object-based database is accessed which comprises geometrical objects representing the topological features with each geometrical object associated with a particular tessellation. The geometrical objects are one of a polygon object, a polyline object and a point object representing the topological features. A tessellation is selected to be displayed. The geometrical objects are fetched which are associated with the tessellations to be displayed. The fetched geometrical objects are drawn on the display.

Abstract: The present invention is a GIS system in which topological information is classified as geometrical objects and uses a region identifier and a geometry attribute to reconstruct each topological feature. The present invention starts from the geometrical objects representing topological features. Each geometrical object has an entry including a region identifier attribute and a geometry attribute defining the geometry of a complete representation of the feature. These geometrical objects are complete in that an entry of the object attribute includes a record for a geometry attribute defining the complete geometry of a complete representation of a topological feature. These complete geometrical objects need not inherit attributes from other objects. The objects are classified as either a polygon object, polyline object, point object or raster object and stored in a respective object-based database.

Abstract: A method and system are disclosed for providing a more accurate position of a mobile receiver even though a signal received by the mobile receiver indicating the position of the mobile receiver is inaccurate. The received signal is used as an estimated indication of the position of the mobile receiver. A database comprises geometrical objects representing navigable routes. The geometrical objects include a geometry attribute defining the geometry of a complete representation of the navigable route. A geometrical object representing a navigable route is determined where the mobile receiver is probably located. The estimated position of the mobile receiver can then be compared against the geometry of the navigable route and against the previous positions in which the mobile receiver was located. The estimated position of the mobile receiver can be adjusted if necessary to provide a more probable position of the mobile receiver.