Constructing Road Geometry

• US 20130328924A1
• Filed: 09/30/2012
• Published: 12/12/2013
• Est. Priority Date: 06/06/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Arikan, Okan, Dumont, Vincent, Moore, Christopher D.
• Granted Patent: US 9,396,563 B2
• Time in Patent Office: Days
• US Class Current: 345/629
• CPC Class Codes: G01C 21/3815 Road data
• CPC Class Codes: G01C 21/3819 Road shape data, e.g. outline of a route
• CPC Class Codes: G01C 21/3867 Geometry of map features, e.g. shape points, polygons or for simplified maps
• CPC Class Codes: G01C 21/387 Organisation of map data, e.g. version management or database structures
• CPC Class Codes: G01C 21/3878 Hierarchical structures, e.g. layering
• CPC Class Codes: G01C 21/3881 Tile-based structures
• CPC Class Codes: G06T 11/00 2D [Two Dimensional] image generation
• CPC Class Codes: G06T 11/20 Drawing from basic elements, e.g. lines or circles
• CPC Class Codes: G06T 11/60 Editing figures and text; Combining figures or text
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: G06T 7/0004 Industrial image inspection
• CPC Class Codes: G09G 5/00 Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators image data processing or generation, in general G06T

Abstract

Some embodiments provide a method for a mapping service. The method generates an initial set of geometries for a road graph defined for a map region. The road graph includes several road segments and junctions aggregated into roads. The method identifies an overlap between a first geometry of a first road segment and a second geometry of a second road segment. The first road segment and the second road segment are parts of different roads and do not meet at a junction. The method automatically modifies at least one of the first and second geometries in order to prevent the first geometry and second geometry from overlapping. In some embodiments each geometry is defined by a set of vertices that specify its boundaries. The method of some embodiments automatically modifies the vertices of at least one of the first and second geometries.

Claims

1. A machine readable medium storing a program for execution by at least one processing unit, the program comprising sets of instructions for:

generating an initial set of geometries for a road graph defined for a map region, the road graph comprising a plurality of road segments and junctions aggregated into roads;

identifying an overlap between a first geometry of a first road segment and a second geometry of a second road segment, wherein the first road segment and the second road segment are parts of different roads and do not meet at a junction; and

automatically modifying at least one of the first and second geometries in order to prevent the first geometry and second geometry from overlapping.

2. The machine readable medium of claim 1, wherein each road segment comprises vertex data that defines the centerline of the road segment.

3. The machine readable medium of claim 2, wherein the set of instructions for automatically modifying at least one of the geometries comprises a set of instructions for moving the centerline vertices of the first and second road segments away from each other.

4. The machine readable medium of claim 3, wherein the centerline vertices are moved a distance related to an amount of the overlap.

5. The machine readable medium of claim 3, wherein the centerline vertices within a particular distance are moved.

6. The machine readable medium of claim 1, wherein the set of instructions for automatically modifying at least one of the first and second geometries comprises a set of instructions for reducing a width of at least one of the geometries.

7. The machine readable medium of claim 6, wherein a width of the first geometry and the width of the second geometry are reduced by an equal amount.

8. The machine readable medium of claim 6, wherein the width of only one of the geometries is reduced.

9. The machine readable medium of claim 1, wherein the program further comprises a set of instructions for automatically defining a road median geometry between the first road segment and the second road segment.

10. The machine readable medium of claim 9, wherein the program further comprises a set of instructions for determining whether the first road segment and second road segment are corresponding halves of a dual carriageway, wherein the road median geometry is only defined when the first road segment and second road segment are corresponding halves of a dual carriageway.

11. For a mapping service, a method comprising:

receiving a road graph for a map region, the road graph comprising (i) a plurality of road segments aggregated into roads and (ii) a plurality of junctions at which two or more road segments intersect;

generating an initial set of geometries for the road segments in the road graph, each geometry defined by a set of vertices that specify boundaries of the geometry;

determining that a first geometry for a first road segment and a second geometry for a second road segment overlap based on locations of the vertices of the first geometry and the vertices of the second geometry, wherein the first road segment and the second road segment do not share a junction; and

automatically modifying the vertices of at least one of the first and second geometries in order to remove the overlap.

12. The method of claim 11, wherein the geometries are used to generate map tiles for download to user devices requesting electronic maps of the map region.

13. The method of claim 11, wherein automatically modifying at least one of the geometries comprises moving centerlines of the first road segment and the second road segment apart from each other, wherein the vertices that specify the boundaries of the first and second road segments are moved with the centerline.

14. The method of claim 13, wherein the centerlines of the first and second road segments are only moved in the vicinity of the overlap.

15. The method of claim 13, wherein an amount of movement of the centerlines is proportional to an amount of overlap.

16. The method of claim 11, wherein automatically modifying at least one of the geometries comprises reducing a width of at least one of the geometries by moving the vertices towards a centerline of the road segment.

17. The method of claim 11, wherein the first and second road segments are at a same elevation.

18. A machine readable medium storing a program for execution by at least one processing unit, the program comprising sets of instructions for:

receiving a road graph for a map region, the road graph comprising a plurality of road segments and junctions of road segments aggregated into roads;

generating geometries for the road segments in the road graph;

generating lane marking geometries for a plurality of the road segments based on at least one attribute of the road segment; and

for at least one junction between a first road segment and a second road segment, automatically generating intersection marking geometries for the juncture.

19. The machine readable medium of claim 18, wherein the attribute comprises a road width.

20. The machine readable medium of claim 18, wherein the attribute comprises a number of lanes.

21. The machine readable medium of claim 18, wherein the attribute comprises a road type.

22. The machine readable medium of claim 21, wherein the road type is automatically associated with a particular number of lanes.