Object-based geographic information system (GIS)

• US 6,247,019 B1
• Filed: 03/17/1998
• Issued: 06/12/2001
• Est. Priority Date: 03/17/1998
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: PRC Public Sector Incorporated
• Inventors: Davies, Frederick Bryan
• Primary Examiner(s): Vu, Kim
• Assistant Examiner(s): Corrielus, Jean M.
• Application Number:
  US09/042,811
• Time in Patent Office: 1,183 Days
• Field of Search: 340/989, 340/990, 340/995, 701/207, 701/208, 707/103, 434/152
• US Class Current: 1/1
• CPC Class Codes: G01C 21/3867 Geometry of map features, e.g. shape points, polygons or for simplified maps
• CPC Class Codes: G01C 21/3878 Hierarchical structures, e.g. layering
• CPC Class Codes: G01C 21/3881 Tile-based structures
• CPC Class Codes: G06F 16/289 Object oriented databases
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure

Abstract

The present invention is a GIS system in which topological information is classified as geometrical objects and uses a region identifier and a geometry attribute to reconstruct each topological feature. The present invention starts from the geometrical objects representing topological features. Each geometrical object has an entry including a region identifier attribute and a geometry attribute defining the geometry of a complete representation of the feature. These geometrical objects are complete in that an entry of the object attribute includes a record for a geometry attribute defining the complete geometry of a complete representation of a topological feature. These complete geometrical objects need not inherit attributes from other objects. The objects are classified as either a polygon object, polyline object, point object or raster object and stored in a respective object-based database. Using this data structure, a topological region can be displayed in real time by accessing this object-based data structure and loading the data structure associated with the topological region into a buffer. The geometrical objects associated with the topological region are then fetched from the buffer and loaded into a virtual blackboard. The fetched geometrical objects are then drawn on a display in real time.

Claims

1. A method for displaying a topology having topological features on a display, the method comprising the steps of:

selecting a topological region to display;

accessing at least one object-based database comprising geometrical objects representing topological features, each geometrical object comprising a region identifier attribute and a geometry attribute defining the geometry of a complete representation of a topological feature;

fetching geometrical objects having a region identifier attribute associated with the selected topological region from the at least one accessed database; and

drawing representations of topological features in real time using the geometry attributes from the fetched geometrical objects on the display.

2. The method of claim 1, wherein said geometrical features are associated with one or more topological region, the geometrical objects being one of a polygon object, a polyline object and a point object.

3. The method of claim 1, wherein said fetching step includes the step of placing the geometrical objects into a buffer.

4. The method of claim 1, wherein attributes of the geometrical objects are not inherited from an ancestor.

5. The method of claim 1, wherein said drawing step includes the step of determining a visibility level for each of the geometrical objects.

6. The method of claim 5, wherein said determining step includes the step of building a link list which represents the visibility level that is associated with each of the geometrical objects.

7. The method of claim 1, wherein said fetching step includes the step of drawing geometrical objects in a virtual blackboard.

8. The method of claim 1, wherein said steps of accessing, fetching and drawing occur in real time.

9. The method of claim 1, wherein the geometrical objects have an attribute of a feature identifier.

10. The method of claim 1, wherein said accessing step includes the step of accessing an object-based data base.

11. The method of claim 1, wherein said drawing step may include the step of overlapping some of the geometrical objects.

12. The method of claim 1, wherein said drawing step includes the step of following an order of output in which polygon objects are output first, polyline objects are output second and point objects are output third.

13. The method of claim 12, further including the steps of accessing raster objects and outputting at least some of the raster objects wherein said raster objects are output before the polygon objects.

14. The method of claim 12, wherein said outputting step includes the steps of drawing the raster objects into a virtual blackboard.

15. A method of building an object-based database of a topology having topological features, comprising the steps of:

identifying the topological features as geometrical objects, the geometrical objects being one of a polygon object, a polyline object and a point object;

storing the identified polygon objects in a polygon object database, each polygon object comprising a region identifier attribute and a geometry attribute defining the geometry of a complete representation of a topological feature;

storing the identified polyline objects in a polyline object database, each polyline object comprising a region identifier attribute and a geometry attribute defining the geometry of a complete representation of a topological feature; and

storing the identified point objects in a point object database, each point object comprising a region identifier attribute and a geometry attribute defining the geometry of a complete representation of a topological feature;

wherein when the object-based database is accessed, a topological region can be displayed in real time.

16. The method of claim 15, wherein said identifying step includes the steps of:

loading the topology into a virtual blackboard;

assigning attributes to each of geometrical objects; and

storing the attributes assigned to the geometrical objects in a respective database.

17. The method of claim 15, further including the step of storing background information of the topology as raster objects in a raster object database.

18. The method of claim 15, wherein said identifying step includes the step of assigning for each polygon object the attributes of an identifier, a feature identifier, a visibility level and a color.

19. The method of claim 15, wherein said identifying step includes the step of assigning for each polyline object, the attributes of an identifier, a feature identifier, a visibility level and a color.

20. The method of claim 15, wherein said identifying step includes the step of assigning for each point object the attributes of an identifier, a feature identifier, a visibility level and a color.

21. The method of claim 15, wherein the topology includes information obtained from real world information.

22. An article, comprising:

at least one sequence of machine executable instructions;

a medium bearing the executable instructions in machine readable form, wherein execution of the instructions by one or more processors causes the one or more processors to;

access at least one object-based database comprising geometrical objects representing topological features of a topology, each geometrical object comprising a region identifier attribute and a geometry attribute defining the geometry of a complete representation of a topological feature;

fetch the geometrical objects having a region identifier attribute associated with a selected topological region from the at least one accessed database;

draw representations of topological features using the geometry attributes from the fetched geometrical objects on a display in real time.

23. An article as in claim 22, the geometrical objects being one of a polygon object, a polyline object and a point object.

24. An article as in claim 22, wherein the medium comprises a storage medium.

25. An article as in claim 22, wherein the medium comprises a carrier wave.

26. An article as in claim 22, wherein the medium comprises a communications link carrying a signal containing the executable instructions.

27. A computer architecture for displaying a topology having topological features on a display, comprising:

selecting means for selecting a topological region to display;

accessing means for accessing at least one object-based database comprising geometrical objects representing topological features, each geometrical object comprising a region identifier attribute and a geometry attribute defining the geometry of a complete representation of a topological feature;

fetching means for fetching geometrical objects having a region identifier attribute associated with the selected topological region from the at least one accessed database; and

drawing means for drawing representations of topological features using the geometry attributes from the fetched geometrical objects on the display in real time.

28. A computer system comprising:

a processor; and

a memory coupled to said processor, the memory having stored therein sequences of instructions, which, when executed by said processor, cause said processor to perform the steps of;

selecting a topological region to display;

accessing at least one object-based database comprising geometrical objects representing topological features, each geometrical object comprising a region identifier attribute and a geometry attribute defining the geometry of a complete representation of a topological feature;

fetching geometrical objects having a region identifier attribute associated with the selected topological region from the at least one accessed database; and

drawing representations of topological features using the geometry attributes from the fetched geometrical objects on the display in real time.

29. A computer-readable medium having a data structure stored thereon for access by a GIS system to enable display of topological regions having topological features in real time, the data structure comprising:

a polygon object database having polygon objects, each polygon object representing a topological feature, each polygon object comprising a region identifier attribute and a geometry attribute defining the geometry of a complete representation of a topological feature;

a polyline object database having polyline objects, each polyline object associated with a topological region, each polyline object comprising a region identifier attribute and a geometry attribute defining the geometry of a complete representation of a topological feature; and

a point object database having point objects, each point object associated with a topological region, each point object comprising a region identifier attribute and a geometry attribute defining the geometry of a complete representation of a topological feature.

30. The computer-readable medium of claim 29, further comprising a raster object database having raster objects, each raster object associated with a topological region, each raster object comprising a region identifier attribute and a bitmap attribute.

31. A data structure for manipulation by a processor to enable display of topological regions in real time on a display having topological features comprising:

a polygon object database having polygon objects, each polygon object representing a topological feature, each polygon object comprising a region identifier attribute and a geometry attribute defining the geometry of a complete representation of a topological feature;

a polyline object database having polyline objects, each polyline object associated with a topological region, each polyline object comprising a region identifier attribute and a geometry attribute defining the geometry of a complete representation of a topological feature; and

a point object database having point objects, each point object associated with a topological region, each point object comprising a region identifier attribute and a geometry attribute defining the geometry of a complete representation of a topological feature.

32. The data structure of claim 31, further comprising a raster object database having raster objects, each raster object associated with a topological region, each raster object comprising a region identifier attribute and a bitmap attribute.