Display method and apparatus for navigation system

#This invention relates to a display method and apparatus for navigation system for displaying “Point of Interest (POI)” icons on a map image, and more particularly, to a display method and apparatus which is capable of more clearly displaying the POI icons and their positions in a region of attention by displacing the POI icons in radial directions relative to a reference center.

#A navigation system performs travel guidance for enabling a user to easily and quickly reach the selected destination. A typical example is a vehicle navigation system where a user drives a car having a vehicle navigation system. Such a navigation system detects the position of the user or user's vehicle, reads out map data pertaining to an, area at the current vehicle position from a data storage medium, for example, a CD-ROM (compact disc read-only memory), a DVD (digital versatile disc), or a hard disc. Alternatively, such map data can be provided to the user from a remote server through a communication network such as Internet. The navigation system displays a map image on a monitor screen while superimposing a mark representing the current location of the user on the map image.

#When a destination is set, the navigation system starts a route guidance function for setting a guided route from the start point to the destination. To determine the guided route to the destination, the navigation system calculates and determines an optimum route to the destination based on various parameters. For example, the guided route is determined based on the shortest way to reach the destination, the route preferring freeways to surface roads, the least expensive way to the destination, or the route without using toll road, and the like.

#FIGS. 1A-1H are schematic diagrams showing an example of operational process and screen display of a navigation system for implementing the POI displacement method and apparatus of the present invention.

#FIGS. 2A-2E are schematic diagrams showing an example of operational process and screen display of a navigation system for specifying a destination by using POI icons on the map image in the conventional technology.

#FIGS. 3A-3B are schematic diagrams showing a display example corresponding to the method of FIGS. 2A-2E when many POI icons exist within a small area.

#The present invention is described in detail with reference to the accompanying drawings. The navigation system of the present invention is designed to enable a user to easily see an accurate position of points of interest (POIs) by their icons (POI icons) on a map image. In particular, the display method of the present invention is useful when many POI icons are located in a small area. The navigation system displaces the POI icons within a region of attention in radial directions to a position rim or to positions in proportion to the original POI positions relative to a center. Typically, such a region of attention is defined by a cursor of a navigation screen, however any predefined region mark can be used. Preferably, a size of such a region mark can be adjustable by a user.

#Such a displacement operation is initiated either automatically or by an instruction from the user. Thus, by changing a position or a size of the region mark on the map image, the navigation system starts displacing the POI icons within the region mark. If the original positions of the POI icons before the displacement now become outside of the region mark, the navigation system reverts back the displaced POI icons to the original positions. The navigation system displays position marks showing the original positions of the POI icons and connects the position marks to the displaced POI icons through lead lines. Accordingly, the user can easily identify locations of the POIs by combinations of the displaced POI icons, lead lines, position rim, and the original position marks.

#FIG. 4 is a block diagram showing an example of structure of a vehicle navigation system implementing the present invention. While the vehicle navigation system is explained for an illustration purpose, the present invention can also be applied to other types of navigation system. For example, the present invention can be advantageously used in a portable navigation device such as a one implemented in a PDA (personal digital assistant) device, a lap-top computer, or other hand-held devices.