Map display device, map display method, and computer program for use in map display device

A map display device, comprising:

• map storing means for storing map information;
• map acquiring means for acquiring map information that shows a map of an area specified by a current position of the map display device, from the map storing means, the map having a portion which is to be enlarged and/or a portion which is to be contracted, the portion to be enlarged and the portion to be contracted being referred to as an enlarged portion and a contracted portion respectively;
• surface storing means for storing surface information that defines a virtual screen having a form of a curved surface which depends on a positioning of the enlarged portion and/or the contracted portion on the map shown by the acquired map information;
• and
• projecting/displaying means for projecting the map shown by the acquired map information onto the virtual screen defined by the surface information, and displaying a projected image obtained as a result of the projection.

A map display method for use in a map display device for displaying a map with one or more portions enlarged and/or contracted, comprising:

• a map receiving step for receiving map information that shows a map of an area specified by a current position of the map display device, wherein surface information that defines a curved surface whose form depends on a positioning of one or more portions to be enlarged and/or contracted on the map shown by the map information is stored in a storing unit in the map display device;
• a mapping step for mapping the map shown by the map information, onto the curved surface defined by the surface information, to generate a mapped image;
• and
• a projecting/displaying step for projecting the mapped image onto a flat virtual screen, and displaying the projected image.

A computer program recorded on a computer-readable recording medium, for use in a map display device that displays a map with one or more portions enlarged and/or contracted, the program comprising:

• a map receiving step for receiving map information that shows a map of an area specified by a current position of the map display device, wherein surface information that defines a curved surface whose form depends on a positioning of one or more portions to be enlarged and/or contracted on the map shown by the map information is stored in a storing unit in the map display device;
• a mapping step for mapping the map shown by the map information, onto the curved surface defined by the surface information, to generate a mapped image;
• and
• a projecting/displaying step for projecting the mapped image onto a flat virtual screen, and displaying the projected image.