Map database device, map display apparatus and recording medium capable of efficiently having and utilizing height data

• US 6,621,494 B2
• Filed: 06/04/2001
• Issued: 09/16/2003
• Est. Priority Date: 05/09/1997
• Status: Expired due to Term

• Current Assignee: Clarion Co., Ltd. (Faurecia SA)
• Original Assignee: Xanavi Informatics Corporation (Hitachi, Ltd.)
• Inventors: Matsuoka, Youji, Ohuchi, Katsuo
• Primary Examiner(s): Padmanabhan, Mano
• Application Number:
  US09/871,807
• Publication Number:
  US 20010028350A1
• Time in Patent Office: 834 Days
• Field of Search: 345/420, 345/427, 345/582, 345/585, 345/589, 345/592, 345/606, 345/419, 340/990, 340/995, 701/209
• US Class Current: 345/427
• CPC Class Codes: G01C 21/3635 Guidance using 3D or perspective road maps
• CPC Class Codes: G01C 21/3667 Display of a road map G01C21/3614 takes precedence; guidance using 3D or perspective road maps G01C21/3635
• CPC Class Codes: G08G 1/0969 having a display in the form of a map
• CPC Class Codes: G09B 29/106 using electronic means

Abstract

The map database device according to the present invention is employed to display a bird'"'"'s eye view map achieved by converting a two-dimensional map into a display format adopting a bird'"'"'s eye view method. And the map data base device includes: a height data portion in which height data respectively corresponding to altitudes of a plurality of areas into which the two-dimensional map is divided are respectively stored in correspondence to the areas.

Claims

1. A map database device for displaying a bird'"'"'s eye view map by converting a two-dimensional map into a display format of a bird'"'"'s eye view method, comprising:

an element point data portion in which positional coordinates of each element point existing in said two-dimensional map are stored, the two-dimensional map being divided into a plurality of areas; and

a height data portion in which a plurality of height data respectively corresponding to altitudes of the plurality of areas into which said two-dimensional map is divided are respectively stored, each of the plurality of areas being assigned only one of the plurality of height data, wherein

one of the plurality of height data corresponding to one of the plurality of areas is common for all element points existing in the one of the plurality of areas; and

the plurality of height data are used for displaying the bird'"'"'s eye view map.

2. A map database device for displaying a bird'"'"'s eye view map by converting a two-dimensional map into a display format of a bird'"'"'s eye view method, comprising:

a height data portion in which a plurality of height data respectively corresponding to altitudes of a plurality of areas into which said two-dimensional map is divided are respectively stored, each one of the plurality of areas being assigned only one of the plurality of height data; and

a road data portion in which a road extending within said two-dimensional map is expressed with element points, and positional coordinates of each of the element points in said two-dimensional map are stored, wherein

one of the plurality of height data corresponding to one of the plurality of areas is common for all element points existing in the one of the plurality of areas; and

the plurality of height data are used for displaying the bird'"'"'s eye view map.

3. A map display apparatus for displaying a bird'"'"'s eye view map by converting a two-dimensional map into a display format of a bird'"'"'s eye view method, comprising:

a database device that includes at least a height data portion in which a plurality of height data respectively corresponding to altitudes of a plurality of areas into which said two-dimensional map is divided are respectively stored, each One of the plurality of areas being assigned only one of the plurality of height data, and a road data portion in which a road extending within said two-dimensional map is expressed with element points and positional coordinates of each of the element points in said two-dimensional map are stored; and

a calculation device that performs calculation to determine in which of said areas each of the element points read out from said road data portion is located, reads out height data corresponding to one of said areas ascertained through said calculation from said height data portion to use as height data for all element points existing in the one of said areas ascertained through said calculation, and calculates coordinate values of each of the plurality of element points on said bird'"'"'s eye view map to be displayed on a monitor screen based upon positional coordinates read out from said road data portion and said height data read out from said height data portion.

4. A map display apparatus for displaying a bird'"'"'s eye view map by converting a two-dimensional map into a display format of a bird'"'"'s eye view method, comprising:

an element point data portion in which positional coordinates of each of element points existing in said two-dimensional map are stored, the two-dimensional map being divided into a plurality of areas;

a height data portion in which a plurality of height data respectively corresponding to altitudes of a plurality of areas into which said two-dimensional map is divided are respectively stored, each one of the plurality of areas being assigned only one of the plurality of height data, one of the plurality of height data corresponding to one of the plurality of areas being common for all element points existing in the one of the plurality of areas;

a calculation device that calculates coordinate values on said bird'"'"'s eye view map to be displayed on a monitor screen for a point in each of the areas based upon positional coordinates and height data of the point; and

a gradation device that achieves gradation display of areas enclosed by the points on the monitor screen in correspondence to heights of the individual points.

5. A map display apparatus for displaying a bird'"'"'s eye view map by converting a two-dimensional map into a display format bird'"'"'s eye view method, comprising:

a map database device that includes a height data portion in which height data respectively corresponding to altitudes of a plurality of areas into which said two-dimensional map is divided are respectively stored in correspondence to the areas, a road data portion in which a road within said two-dimensional map is expressed with a plurality of element points and positional coordinates of each of the element points of the road in said two-dimensional map are stored, and a tunnel data portion in which a tunnel within said two-dimensional map is expressed with a plurality of element points and positional coordinates of each of the element points of the tunnel in said two-dimensional map are stored; and

a calculation device that comprises a first calculation unit that calculates coordinate values of said element points of the road on said bird'"'"'s eye view map to be displayed on a monitor screen based upon positional coordinates read out from said road data portion and height data read out from said height data portion corresponding to areas in which said element points of the road exist, a second calculation unit that performs calculation to determine in which of said areas are located element points corresponding to an entrance and an exit among said element points of the tunnel read out from said tunnel data portion, a reading unit that reads out height data corresponding to the areas determined through said calculation from said height data portion to use as height data of said entrance and said exit, an interpolation unit that interpolates other element points of the tunnel with said height data of said entrance and said exit to create height data therefor without using height data in said height data portion corresponding to areas in which said other element points of the tunnel exist, and a third calculation unit that calculates coordinate values of said element points of the tunnel on said bird'"'"'s eye view map to be displayed on a monitor screen based upon positional coordinates read out from said tunnel data portion and height data obtained through interpolating calculation.

6. A map display apparatus for displaying a bird'"'"'s eye view map by converting a two-dimensional map into a display format bird'"'"'s eye view method, comprising:

a height data portion in which height data respectively corresponding to altitudes of a plurality of areas into which said two-dimensional map is divided are respectively stored in correspondence to the areas;

a calculation device that calculates coordinate values on said bird'"'"'s eye view map to be displayed on a monitor screen for a point in each of said areas based upon positional coordinates and height data of the point; and

a gradation device that comprises a height difference calculation unit that calculates a difference between a minimum height and a maximum height among a plurality of areas enclosed by said points within said monitor screen, a first assigning unit that respectively assigns m sets of color data among height color data, which is provided in a predetermined order in correspondence to heights in advance with a fixed gradation pitch, to m color palettes in the predetermined order when said difference is equal to or less than a specific value, a gradation pitch calculation unit that calculates a variable gradation pitch, which is larger than the fixed gradation pitch, by dividing said difference by m if said difference exceeds said specific value, and a second assigning unit that assigns m sets of color data among said height color data provided in said predetermined order to said m color palettes with said variable gradation pitch, in order to achieve gradation display of each of areas enclosed by the points on the monitor screen in correspondence to heights of the individual points.

7. A product which can be read by a computer, comprising a recording medium in which:

map data that has an element point data portion in which positional coordinates of each of element points existing in a two-dimensional map are stored and a height data portion in which height data respectively corresponding to altitudes of a plurality of areas into which the two-dimensional map is divided are respectively stored, each of the plurality of areas being assigned only one of the plurality of height data, for displaying a bird'"'"'s eye view map by converting the two-dimensional map into a display format of bird'"'"'s eye view method, wherein

said height data corresponding to one of the plurality of areas is common for all element points existing in the one of the plurality of areas; and

the plurality of height data are used for displaying the bird'"'"'s eye view map.

8. A map display apparatus for displaying a bird'"'"'s eye view map by converting a two-dimensional map into a display format of a bird'"'"'s eye view method, comprising:

map data that include two-dimensional map data and height data; and

a three-dimensional bird'"'"'s eye view map display device that three-dimensionally displays said bird'"'"'s eye view map on a display screen based upon said map data taking said height data into consideration, wherein;

said map data comprise detailed map data at a large scaling factor and wide range map data at a scaling factor smaller than said detailed data;

said display screen is divided into, at least, a first display area and a second display area adjacent to said first display area, said first display area being set at a side closer to a viewpoint in a bird'"'"'s eye view method, and said second display area being set on a side further away from said viewpoint; and

said three-dimensional bird'"'"'s eye view map display device displays a three-dimensional bird'"'"'s eye view map in said first display area based upon said detailed map data, displays a three-dimensional bird'"'"'s eye view map in said second display area based upon said wide range map data, sets a hypothetical line of sight that extends from said viewpoint to pass through a point corresponding to a boundary of said first area and said second area on said display screen, and determines ranges, over which said detailed map data and said wide range map data are to be used, in reference to a point at which said line of sight intersects a line that extends in a direction of said line of sight and corresponds to a ground level calculated by taking said height data into consideration, the calculated ground level having differences in elevation.