Unit and program for displaying map

• US 7,199,800 B2
• Filed: 08/08/2003
• Issued: 04/03/2007
• Est. Priority Date: 08/09/2002
• Status: Expired due to Fees

• Current Assignee: Aisin AW Company Limited (Aisin Corp.)
• Original Assignee: Aisin AW Company Limited (Aisin Corp.)
• Inventors: Ogawa, Tsuyoshi
• Primary Examiner(s): Tung; Kee M.
• Assistant Examiner(s): Nguyen; Hau
• Application Number:
  US10/636,563
• Publication Number:
  US 20040066316A1
• Time in Patent Office: 1,334 Days
• Field of Search: 345/501, 345/555, 345/536, 345/537, 340/988, 340/990, 340/995.1, 34099511-99526
• US Class Current: 345/537
• CPC Class Codes: G01C 21/367 Details, e.g. road map scale, orientation, zooming, illumination, level of detail, scrolling of road map or positioning of current position marker
• CPC Class Codes: G01C 21/3673 Labelling using text of road map data items, e.g. road names, POI names
• CPC Class Codes: G01C 21/3852 Data derived from aerial or satellite images
• CPC Class Codes: G08G 1/0969 having a display in the form of a map

Abstract

The invention provides a map display unit including a first memory for storing map data and a drawing memory for drawing the map data and displaying display-area data and a display. The map display unit includes a unit to read and decompress compressed map data stored in blocks in a data storage medium and to store the decompressed map data in the first memory; a unit to draw the stored map data in the drawing memory; and a unit to determine the display area and to display the display-area data of the drawing area in the drawing memory on the display. When there is no display-area data in the first memory, compressed map data is read and decompressed from the data storage medium by the data decompression unit. The map display unit further includes an environmental change sensor and controllers to vary the color tone of the map data with the environmental change, thereby displaying easily viewable map data.

Claims

1. A map display unit including a first memory for storing map data and a drawing memory for drawing the map data and displaying display-area data of a drawing area in the drawing memory on a display, comprising:

data-reading means for selectively reading compressed map data and uncompressed map data from a data storage medium;

data-decompressing means for decompressing the compressed map data read out by the data-reading means and storing the decompressed map data in the first memory;

drawing means for drawing either of the uncompressed map data read out by the data-reading means or the map data stored in the first memory in the drawing memory;

display-control means for determining the display area and displaying the display-area data of the drawing area in the drawing memory on the display; and

map-selecting means for selecting a map to be displayed, wherein the map-selecting means switches which of the uncompressed map data or the map data the drawing means draws in the drawing memory;

wherein the map-selecting means includes means for determining the velocity of a vehicle and switches the map to be displayed depending on whether the velocity has exceeded a threshold.

2. The map display unit according to claim 1, wherein the compressed map data is raster data and the uncompressed map data is vector data.

3. The map display unit according to claim 2, wherein the raster data is satellite photograph data.

4. The map display unit of claim 1, further comprising the data storage medium.

5. A map display method including a first memory for storing map data and a drawing memory for drawing the map data and displaying display-area data of a drawing area in the drawing memory on a display, comprising:

selectively reading compressed map data and uncompressed map data from a data storage medium;

decompressing the compressed map data read out by the data-reading means and storing the decompressed map data in a first memory;

drawing either of the uncompressed map data read out by the data-reading means or the map data stored in the first memory in a drawing memory;

determining the display area and displaying the display-area data of the drawing area in the drawing memory on the display;

selecting a map to be displayed;

switching which of the uncompressed map data or the map data the drawing means draws in the drawing memory;

determining the velocity of a vehicle; and

switching the map to be displayed depending on whether the velocity has exceeded a threshold.