METHOD OF LABELLING A HIGHLY CURVED PATH ON A MAP RENDERED ON A WIRELESS COMMUNICATIONS DEVICE

• US 20070229513A1
• Filed: 03/14/2007
• Published: 10/04/2007
• Est. Priority Date: 03/31/2006
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Research In Motion Limited (Blackberry Limited)
• Inventors: Bowman, Gordon Gregory
• Granted Patent: US 9,099,056 B2
• Time in Patent Office: Days
• US Class Current: 345/467
• CPC Class Codes: G01C 21/367 Details, e.g. road map scale, orientation, zooming, illumination, level of detail, scrolling of road map or positioning of current position marker
• CPC Class Codes: G01C 21/3673 Labelling using text of road map data items, e.g. road names, POI names
• CPC Class Codes: G06F 16/29 Geographical information databases
• CPC Class Codes: G06F 16/9577 Optimising the visualization of content, e.g. distillation of HTML documents
• CPC Class Codes: G06F 3/0481 based on specific properties of the displayed interaction object or a metaphor-based environment, e.g. interaction with desktop elements like windows or icons, or assisted by a cursor's changing behaviour or appearance
• CPC Class Codes: G06F 3/147 using display panels
• CPC Class Codes: G06F 40/103 Formatting, i.e. changing of presentation of documents automatic justification G06F40/189; automatic line break hyphenation G06F40/191
• CPC Class Codes: G06T 11/60 Editing figures and text; Combining figures or text
• CPC Class Codes: G06T 15/503 Blending, e.g. for anti-aliasing
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: G06T 19/00 Manipulating 3D models or images for computer graphics
• CPC Class Codes: G06T 2219/004 Annotating, labelling
• CPC Class Codes: G08G 1/096805 where the transmitted instructions are used to compute a route
• CPC Class Codes: G08G 1/0969 having a display in the form of a map
• CPC Class Codes: G09B 29/10 Map spot or coordinate position indicators; Map reading aids optical projection apparatus per se G03B
• CPC Class Codes: G09B 29/106 using electronic means
• CPC Class Codes: G09G 2340/0492 Change of orientation of the displayed image, e.g. upside-down, mirrored
• CPC Class Codes: G09G 2340/10 Mixing of images, i.e. displayed pixel being the result of an operation, e.g. adding, on the corresponding input pixels
• CPC Class Codes: G09G 2340/145 related to small screens
• CPC Class Codes: G09G 5/377 for mixing or overlaying two or more graphic patterns G09G5/02, G09G5/397 take precedence

Abstract

In displaying a map on a wireless communications device, a method is provided that resolves labelling of sharp curves. The method entails a determination of whether a curvature of a map element associated with the map feature exceeds a predetermined threshold (e.g. whether a rate of change in slope of a path or the change in angular orientation of each successive character in the label exceeds a threshold that is a function of zoom level. If the curvature exceeds the threshold, the label is rendered on the map in a new map location that avoids the map location where the curvature exceeds the threshold.

Claims

1. A method of displaying a map on a wireless communications device, the method comprising steps of:

obtaining map data for rendering the map to be displayed on the wireless communications device, the map data including label data for rendering a label for identifying a map feature on the map;

determining whether a curvature of a map element associated with the map feature exceeds a predetermined threshold; and

rendering the label on the map in a new map location that avoids the map location where the curvature exceeds the predetermined threshold.

2. The method as claimed in claim 1 wherein the step of determining whether the curvature exceeds the predetermined threshold comprises a step of determining a rate of change in slope

$\frac{{\partial }^{}}{}$

2 

y ∂

x 2

of a map feature at the map location where the label is to be rendered.

3. The method as claimed in claim 1 wherein the step of determining whether the curvature exceeds the predetermined threshold comprises a step of determining a rate of change in slope

$\frac{{\partial }^{}}{}$

2 

y ∂

x 2

of a path at the map location where the label is to be rendered.

4. The method as claimed in claim 1 wherein the step of determining whether the curvature exceeds the predetermined threshold comprises steps of:

virtually rendering the label along its respective path by provisionally orienting each character of the label; and

determining whether a change in angular orientation of each character in the label relative to its preceding character in the label exceeds a predetermined angular threshold.

5. The method as claimed in claim 1 wherein the predetermined threshold varies as a function of a zoom level of the map.

6. The method as claimed in claim 2 wherein the predetermined threshold varies as a function of a zoom level of the map.

7. The method as claimed in claim 3 wherein the predetermined threshold varies as a function of a zoom level of the map.

8. The method as claimed in claim 4 wherein the predetermined threshold varies as a function of a zoom level of the map.

9. The method as claimed in claim 1 further comprising steps of:

generating a collision-avoidance array representative of the map to be rendered for testing potential label positions prior to actually rendering the labels on the map; and

populating the collision-avoidance array by designating one or more undesirable locations in the array corresponding to map locations on the map where the curvature exceeds the predetermined threshold.

10. The method as claimed in claim 2 further comprising steps of:

generating a collision-avoidance array representative of the map to be rendered for testing potential label positions prior to actually rendering the labels on the map; and

populating the collision-avoidance array by designating one or more undesirable locations in the array corresponding to map locations on the map where the curvature exceeds the predetermined threshold.

11. The method as claimed in claim 3 further comprising steps of:

generating a collision-avoidance array representative of the map to be rendered for testing potential label positions prior to actually rendering the labels on the map; and

populating the collision-avoidance array by designating one or more undesirable locations in the array corresponding to map locations on the map where the curvature exceeds the predetermined threshold.

12. The method as claimed in claim 4 further comprising steps of:

generating a collision-avoidance array representative of the map to be rendered for testing potential label positions prior to actually rendering the labels on the map; and

populating the collision-avoidance array by designating one or more undesirable locations in the array corresponding to map locations on the map where the curvature exceeds the predetermined threshold.

13. A computer program product comprising code adapted to perform the steps of claim 1 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.

14. The computer program product comprising code adapted to perform the steps of claim 2 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.

15. The computer program product comprising code adapted to perform the steps of claim 3 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.

16. The computer program product comprising code adapted to perform the steps of claim 4 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.

17. The computer program product comprising code adapted to perform the steps of claim 5 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.

18. The computer program product comprising code adapted to perform the steps of claim 6 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.

19. The computer program product comprising code adapted to perform the steps of claim 7 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.

20. The computer program product comprising code adapted to perform the steps of claim 8 when the computer program product is loaded into memory and executed on a processor of a-wireless communications device.

21. The computer program product comprising code adapted to perform the steps of claim 9 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.

22. The computer program product comprising code adapted to perform the steps of claim 10 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.

23. The computer program product comprising code adapted to perform the steps of claim 11 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.

24. The computer program product comprising code adapted to perform the steps of claim 12 when the computer program product is loaded into memory and executed on a processor of a wireless communications device.

25. A wireless communications device for enabling a user of the device to display a map on the device, the wireless device comprising:

an input device for enabling the user to cause the device to obtain map data for rendering the map to be displayed on a display of the device, the map data including label data for rendering labels on the map for identifying one or more map features; and

a memory for storing code to instruct a processor to;

obtain map data for rendering the map to be displayed on the wireless communications device, the map data including label data for rendering a label for identifying a map feature on the map;

determine whether a curvature of a map element associated with the map feature exceeds a predetermined threshold; and

render the label on the map in a new map location that avoids the map location where the curvature exceeds the predetermined threshold.

26. The wireless communications device as claimed in claim 25 wherein the processor determines a rate of change in slope ∂

²y/∂

x² of a map feature at the map location where the label is to be rendered.

27. The wireless communications device as claimed in claim 25 wherein the processor determines a rate of change in slope ∂

²y/∂

x² of a path at the map location where the label is to be rendered.

28. The wireless communications device as claimed in claim 25 wherein the processor virtually renders the label along its respective path by provisionally orienting each character of the label and then determines whether a change in angular orientation of each character in the label relative to its preceding character in the label exceeds a predetermined angular threshold.

29. The wireless communications device as claimed in claim 25 wherein the predetermined threshold varies as a function of a zoom level of the map.

30. The wireless communications device as claimed in claim 25 wherein the processor generates a collision-avoidance array representative of the map to be rendered for testing potential label positions prior to actually rendering the labels on the map and then populates the collision-avoidance array by designating one or more undesirable locations in the array corresponding to map locations on the map where the curvature exceeds the predetermined threshold.