A METHOD OF GENERATING CURVED BASELINE FOR MAP LABELING

• US 20080198162A1
• Filed: 02/16/2007
• Published: 08/21/2008
• Est. Priority Date: 02/16/2007
• Status: Active Grant

• Current Assignee: MiTAC International Corporation (MiTAC Holdings Corp.)
• Original Assignee: Magellan Navigation Incorporated (MiTAC Holdings Corp.)
• Inventors: Ni, Hongjie
• Granted Patent: US 7,692,655 B2
• Time in Patent Office: Days
• US Class Current: 345/442
• CPC Class Codes: G01C 21/3673 Labelling using text of road map data items, e.g. road names, POI names
• CPC Class Codes: G06T 11/203 Drawing of straight lines or curves
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: G09B 29/007 using computer methods

Abstract

Apparatus and methods of generating a curved baseline for a map labeling include receiving a polyline P={p₁,p₂, . . . ,p_n} of n points, generating a supporting polyline Q={q₁,q₂, . . . ,q_m} (m≧n) of m points at an expected distance d between polyline P and a curved base line L. A predetermined number of B-Spline points is generated based upon supporting polyline Q. The B-Spline points are then connected to form a curved baseline L for displaying a label.

Claims

1. A method of generating a curved baseline for a map labeling, comprising the steps of:

receiving a polyline P of n points, where P={p₁,p₂, . . . ,p_n};

generating a supporting polyline Q of m points an expected distance d between P and a curved base line L, where Q={q₁,q₂, . . . ,q_m} (m≧

n);

generating a predetermined number of B-Spline points based upon supporting polyline Q; and

outputting the generated B-Spline points.

2. The method of claim 1, wherein said generating support polyline Q step further comprises the step of:

generating points {q₁,q₂, . . . ,q_m} such that each triangle Δ

q_uq_u+1q_u+2 (u=1, 2, . . . ,m−

2) is above polyline P and does not touch P.

3. The method of claim 1, wherein said generating support polyline Q step further comprises the step of:

generating points {q₁,q₂, . . . ,q_m} such that Q satisfies

4. The method of claim 2, wherein said generating support polyline Q step further comprises the step of:

generating first point q₁, wherein;

5. The method of claim 4, wherein said generating support polyline Q step further comprises the step of:

generating last point q_m, wherein;

6. The method of claim 1, further comprising the step of connecting the B-Spline points to form a curved baseline L.

7. The method of claim 6, further comprising the step of using curved baseline L to draw a curved label.

8. At least one processor configured to perform the actions of:

receiving a polyline P of n points, where P={p₁,p₂, . . . ,p_n;

generating a supporting polyline Q of m points an expected distance d between P and a curved base line L, where Q={q₁,q₂, . . . ,q_m} (m≧

n);

generating a predetermined number of B-Spline points based upon supporting polyline Q.

9. A computer program product, comprising:

a computer-readable medium comprising;

a first set of codes for causing a computer to receive a polyline P of n points, where P={p₁,p₂, . . . ,p_n};

a second set of codes for causing a computer to generating a supporting polyline Q of m points at an expected distance d between P and a curved base line L, where Q={q₁,q₂, . . . ,q_m}(m≧

n);

a third set of codes for causing a computer to generate a predetermined number of B-Spline points based upon supporting polyline Q; and

a fourth set of codes for causing a computer to connect the B-Spline points in sequence.

10. A portable end user device operable to generate a curved baseline for map labeling, comprising a computer platform further including:

a processor;

a memory executable by the processor, the memory including a curved baseline generator module that includes;

an input of a polyline P of n points, where P={p₁,p₂, . . . ,p_n};

logic operable to generate a supporting polyline Q of m points at an expected distance d between P and a curved base line L, where Q={q₁,q₂, . . . ,q_m} (m≧

n);

logic operable to generate a predetermined number of B-Spline points based upon the generated supporting polyline Q; and

an output comprising the B-Spline points forming the curved baseline L.

11. The device of claim 10, wherein the portable end user device is a portable GPS device.

12. The device of claim 10, further comprising a display unit operable to display a label drawn on the curved baseline L.