Compact text encoding of latitude/longitude coordinates

• US 7,302,343 B2
• Filed: 07/31/2003
• Issued: 11/27/2007
• Est. Priority Date: 07/31/2003
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Beatty, Bryan
• Primary Examiner(s): To; Tuan C
• Application Number:
  US10/631,611
• Publication Number:
  US 20050023524A1
• Time in Patent Office: 1,580 Days
• Field of Search: 701/200, 701/201, 701/208, 701/213, 701/300, 701/214, 702/5, 707/1, 707/3, 341/50, 715/513, 382/229, 382/309, 382/187, 345/173, 709/217
• US Class Current: 701/214
• CPC Class Codes: G01S 5/0027 of actual mobile position, i.e. position determined on mobile
• CPC Class Codes: G06F 16/9566 URL specific, e.g. using aliases, detecting broken or misspelled links
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching

Abstract

Methods are disclosed for encoding latitude/longitude coordinates within a URL in a relatively compact form. The method includes converting latitude and longitude coordinates from floating-point numbers to non-negative integers. A set of base-N string representations are generated for the integers (N represents the number of characters in an implementation-defined character set being utilized). The latitude string and longitude string are then concatenated to yield a single output string. The output string is utilized as a geographic indicator with a URL.

Claims

1. A computer implemented method of reducing the number of characters required to represent coordinates within a geographically-oriented string, the method comprising:

selecting a character set having a predetermined number of characters;

selecting a maximum level of allowable error;

calculating, based at least in part on the predetermined number of characters and the maximum level of allowable error, a number of character spaces required to represent a coordinate;

deriving a reduced-character string representation of a coordinate based, at least in part, on the predetermined number of characters, the allowable error, and the number of character spaces; and

placing the reduced-character string representation of the coordinate within the geographically-oriented string; and

wherein deriving the reduced-character string representation comprises determining an integer mapping range based at least in part on the number of character spaces, and based at least in part on the predetermined number of characters.

2. The method of claim 1, wherein the geographically-oriented string is a geographically-oriented Uniform Resource Locator.

3. The method of claim 1, wherein deriving a reduced-character string representation further comprises determining a latitude base-N string and a longitude base-N string.

4. The method of claim 3, further comprising concatenating the latitude base-N string and the longitude base-N string to derive a concatenated coordinate string.

5. The method of claim 4, wherein placing the reduced-character string representation within the geographically-oriented string comprises placing the concatenated coordinate string within the geographically-oriented string.

6. A computer implemented method of reducing the number of characters required to represent coordinates within a geographically-oriented string, the method comprising:

selecting a character set having a predetermined number of characters;

selecting a maximum level of allowable error;

calculating, based at least in part on the predetermined number of characters and the maximum level of allowable error, a number of character spaces required to represent a coordinate;

deriving a reduced-character string representation of a coordinate based, at least in part, on the predetermined number of characters, the allowable error, and the number of character spaces, wherein deriving a reduced-character string representation comprises determining an integer mapping range and converting a floating point coordinate to an integer value based at least in part on the size of the integer mapping range; and

placing the reduced-character string representation of the coordinate within the geographically-oriented string.

7. The method of claim 6, wherein converting a floating point coordinate comprises converting a latitude coordinate.

8. The method of claim 6, wherein converting a floating point coordinate comprises converting a longitude coordinate.

9. The method of claim 6, wherein deriving a reduced-character string representation further comprises:

converting the integer value to a base-N string, wherein N represents the predetermined number of characters.

10. The method of claim 6, wherein the geographically-oriented string is a geographically-oriented Uniform Resource Locator.

11. The method of claim 6, wherein deriving the reduced-character string representation comprises determining an integer mapping range.

12. The method of claim 11, wherein determining an integer mapping range comprises determining an integer mapping range based at least in part on the number of character spaces, and based at least in part on the predetermined number of characters.

13. The method of claim 6, wherein deriving a reduced-character string representation further comprises determining a latitude base-N string and a longitude base-N string.

14. The method of claim 13, further comprising concatenating the latitude base-N strong and the longitude base-N string to derive a concatenated coordinate string.

15. The method of claim 14, wherein placing the reduced-character string representation within the geographically-oriented string comprises placing the concatenated coordinate string within the geographically-oriented string.

16. A computer implemented method of reducing the number of characters required to represent coordinates within a geographically-oriented string, the method comprising:

selecting a character set having a predetermined number of characters;

selecting a maximum level of allowable error;

calculating, based at least in part on the predetermined number of characters and the maximum level of allowable error, a number of character spaces required to represent a coordinate;

deriving a reduced-character string representation of a coordinate based, at least in part, on the predetermined number of characters, the allowable error, and the number of character spaces; and

placing the reduced-character string representation of the coordinate within the geographically-oriented string; and

wherein deriving a reduced-character string representation further comprises determining a latitude base-N string and a longitude base-N string, and wherein the method further comprises concatenating the latitude base-N string and the longitude base-N string to derive a concatenated coordinate string.

17. The method of claim 16, wherein placing the reduced-character string representation within the geographically-oriented string comprises placing the concatenated coordinate string within the geographically-oriented string.

18. The method of claim 16, wherein the geographically-oriented string is a geographically-oriented Uniform Resource Locator.

19. The method of claim 16, wherein deriving the reduced-character string representation comprises determining an integer mapping range.

20. The method of claim 19, wherein determining an integer mapping range comprises determining an integer mapping range based at least in part on the number of character spaces, and based at least in part on the predetermined number of characters.