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

• US 20010028350A1
• Filed: 06/04/2001
• Published: 10/11/2001
• Est. Priority Date: 05/09/1997
• Status: Active Grant

• Current Assignee: Clarion Co., Ltd. (Faurecia SA)
• Original Assignee: Xanavi Informatics Corporation (Hitachi, Ltd.)
• Inventors: Matsuoka, Youji, Ohuchi, Katsuo
• Granted Patent: US 6,621,494 B2
• Time in Patent Office: Days
• 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:

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.

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 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; and

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

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

a calculation means for performing calculation to determine in which of said areas said element point read out from said road data portion is located, reading out height data corresponding to said area ascertained through said calculation from said height data portion to use as height data for said element point, and calculating coordinate values of said element point 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 obtained through calculation.

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:

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 means for calculating 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 means for achieving 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, 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 in said two-dimensional map are stored; and

a calculation means for performing calculation to determine which of said areas element points corresponding to an entrance and an exit among said element points read out from said tunnel data portion are located in, reading 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, interpolating other element points with said height data of said entrance and said exit to create height data therefor, and calculating coordinate values of said element points 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 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 means for calculating 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 means for calculating a difference between a minimum height and a maximum height among a plurality of areas enclosed by said points within said monitor screen, respectively assigning m sets of color data among color data determined in advance with fixed gradation pitch to m color palettes in a predetermined order when said difference is equal to or less than a specific value, calculating a variable gradation pitch by dividing said difference by m if said difference exceeds said specific value to assign m sets among said 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 recording medium which can be read by a computer, recording:

map data that has a height data portion in which height data respectively corresponding to altitudes of a plurality of areas into which a two-dimensional map is divided are respectively stored in correspondence to the areas for displaying a bird'"'"'s eye view map by converting the two-dimensional map into a display format of bird'"'"'s eye view method.

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 means for three-dimensionally displaying 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 means 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 corresponding to a ground level calculated by taking said height data into consideration.