Three-dimensional map drawing method and navigation apparatus

• US 6,324,469 B1
• Filed: 03/16/2000
• Issued: 11/27/2001
• Est. Priority Date: 03/16/1999
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd., Xanavi Informatics Corporation (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd., Xanavi Informatics Corporation (Hitachi, Ltd.)
• Inventors: Endo, Yoshinori, Nakamura, Kozo, Okude, Mariko, Hiroshige, Hideo
• Primary Examiner(s): Hernandez, Olga
• Application Number:
  US09/527,564
• Time in Patent Office: 621 Days
• Field of Search: 701/208, 701/211, 701/200, 340/990, 340/995, 340/988, 345/423, 345/441, 345/442
• US Class Current: 701/208
• CPC Class Codes: G01C 21/3638 including 3D objects and buildings three dimensional [3D] modelling, e.g. data description of 3D objects G06T17/00; geographic models G06T17/05

Abstract

Whether the structure data read from the map data correspond to a non-decomposition structure or a decomposition structure, the drawing attribute of the mesh boundary is modified for the decomposition structure, and textures such as windows are mapped on the side wall of the structure by mapping the texture on the side wall of the structure reconstructed after reconstructing the single-bodied structure before decomposition, or mapping the texture progressively on the side wall of the decomposition structure with the stored start point and end point of the texture to be mapped.

Claims

1. A navigation apparatus, comprising:

a map data base storing map information comprising structure data defining structures in terms of a decomposed grid comprising grid areas having a predefined size;

a reader unit which reads map information from the map data base for display in a three-dimensional view;

graphic analysis units which draw a decomposition structure formed by decomposing a single-bodied structure that exists in at least two grid areas, and a non-decomposition structure which does not exist in more than a single grid area;

a data processor programmed to

determine whether structure data contained in map information read from said map data base corresponds to a decomposition structure; and

cause a graphic analysis unit to use plural sets of structure data originated from a single-bodied structure before decomposition among structure data determined to correspond to a decomposition structure, to draw plural decomposition structures corresponding to said structure data as a unified body, so as to reconstruct said single-bodied structure.

2. The navigation apparatus according to claim 1, wherein said map information includes data for determining if said structure data correspond to one of said decomposition structures.

3. A navigation apparatus, comprising:

a map data base storing map information comprising structure data defining three-dimensional structures within a map area;

a display unit; and

a data processor which processes data contained in said map data base, and causes said display unit to display a visually readable representation thereof;

wherein,

said map data are projected into a perspective map which is viewed from a preset observation point along an observation axis forming a designated angle with ground surface;

structures in the projected perspective map are drawn as three-dimensional figures; and

structural walls corresponding to the three-dimensional figures and facing the preset observation point in said perspective map are depicted including texture of said structural walls.

4. The navigation apparatus according to claim 3, wherein texture includes a depiction of windows on said structural walls.

5. A method of displaying navigational map information, comprising:

reading map data comprising structure data defining three-dimensional structures within a map area, from a data base storing said map data; and

displaying said map data in a visually observable form;

wherein

said map data are projected into a perspective map which is viewed from a preset observation point along an observation axis forming a designated angle with ground surface;

structures in the projected perspective map are drawn as three-dimensional figures; and

structural walls corresponding to the three-dimensional figures and facing the preset observation point in said perspective map are depicted including texture of said structural walls.

6. The navigation apparatus according to claim 5, wherein texture includes a depiction of windows on said structural walls.

7. A navigation apparatus having at least a means for reading a map information from a map data base storing a map information of a structure in terms of a decomposed mesh having a predefined size and displaying in a three-dimensional view,

comprising

a couple of drawing means for drawing a decomposition structure formed by decomposing a single-bodied structure existing over plural mesh areas and a non-decomposition structure which does not exist over plural mesh areas;

and

an identifying means for identifying whether structure data contained in said structure information read from said map data base corresponds to said decomposition structure,

wherein

said drawing means for drawing a decomposition structure uses plural sets of structure data originated from an identical single-bodied structure before decomposition among structure data which are judged to correspond to said decomposition structure by said identifying means, and draws plural decomposition structures corresponding to said structure data as a unified body so as to reconstruct said single-bodied structure.

8. A navigation apparatus of claim 7, wherein said map data base stores data for identifying said structure data to correspond to one of said decomposition structures.

9. A storage medium used for displaying a map by a computer and storing a map data containing a map information formed in terms of a decomposed mesh having a designated size, wherein

said map data stores

structure data corresponding to a decomposition structure formed by decomposing an originally single-bodied structure existing over plural mesh areas in terms of each mesh area;

structure data corresponding to a non-decomposition structure existing on a single mesh area; and

identification data used for identifying whether each of said structure data corresponds to said decomposition structure.

10. A storage medium of claim 9, wherein

said map data stores either of link data for linkage among plural structures corresponding to plural decomposition structure originated from an identical single-bodied structure before decomposition; or decomposition point identification data for identifying whether each of a set of points for defining a shape of said decomposition structure is a decomposition point defined newly by a decomposition step in terms of said mesh area.

11. A map display method, in which a map is decomposed into a mesh area having a predefined size, and from a map data base storing information representing a structure existing in an individual mesh area with respect to said individual mesh area, information representing said structure is read, and a perspective map viewed in a predefined angle with respect to a ground surface is displayed with a coordinate transformation, said method comprising:

a decomposition structure drawing step for drawing a single-bodied structure before decomposition by using an information

defined when a structure originally formed as a single body existing over plural mesh areas of said map data base is decomposed for individual mesh areas, and

representing a decomposition structure stored so as to correspond to each of said plural mesh areas;

a non-decomposition structure drawing step for drawing a non-decomposition structure, which does not exist over plural mesh areas; and

an identifying step for identifying whether said structure information read from said map data base corresponds to said decomposition structure;

wherein said decomposition structure drawing step

uses plural sets of structure formation originated from an identical single-bodied structure before decomposition which is judged to correspond to said decomposition structure by said identifying step; and

draws plural decomposition structure corresponding to said plural sets of structure information as a unified body so as to reconstruct said single-bodied structure before decomposition.

12. A map display method of claim 11, wherein

in said decomposition structure drawing step,

a closing line of a side wall forming said decomposition structure is drawn such that it does not establish a decomposition surface of a decomposition structure formed by decomposing said single-bodied structure and existing on a boundary between said mesh areas.

13. A map display method of claim 11, wherein

in said decomposition structure drawing step,

when drawing a closing line of a side wall forming said decomposition structure, whether said closing line is a tangential line forming a decomposition surface of a decomposition structure formed over a boundary between said mesh areas;

and

if said closing line is judged to be said tangential line, said tangential line is drawn in a display mode different from that used for a closing line judged not to be a tangential line, but with less visual attractiveness.

14. A map display method of claim 11, wherein

an information representing said decomposition structure includes at least an information indicating the number of vertices forming said decomposition structure;

in said decomposition structure drawing step,

whether a vertex forming said decomposition structure exists on a boundary between said mesh areas is judged;

if said vertex is judged to be one located on said mesh boundary, whether said vertex is an end point of said decomposition structure is judged;

an identical single-bodied structure from which said decomposition structure is originated is drawn, by using a vertex which is judged to be an end point located on said mesh boundary and a vertex which is not located on said mesh boundary.

15. A map display method of claim 11, wherein

an in formation representing a side wall of said single-bodied structure is reconstructed by using an information of individual side walls of plural decomposition structures originated from an identical single-bodied structure before decomposition;

and

a predefined texture is mapped on a side wall of said reconstructed single bodied structure.

16. A map display method of claim 11, wherein

in said decomposition structure drawing step,

a texture shaped in a predefined size is mapped continuously on individual side walls of plural decomposition structures originated from an identical single-bodied structure before decomposition.