SYSTEM AND METHOD FOR PROVIDING EFFICIENT ACCESS TO DIGITAL MAP DATA

• US 20090006480A1
• Filed: 06/27/2008
• Published: 01/01/2009
• Est. Priority Date: 06/27/2002
• Status: Abandoned Application

• Current Assignee: Tele Atlas North America (TomTom NV)
• Original Assignee: Tele Atlas North America (TomTom NV)
• Inventors: Fuchs, Gil, Mathis, Darrell L.
• Application Number:
  US12/163,840
• Publication Number:
  US 20090006480A1
• Time in Patent Office: Days
• US Class Current: 1/1
• 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: 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

Abstract

A system and method for providing efficient access to digital map data. An embodiment of the present invention is generally related to systems for accessing, displaying, editing and using digital maps. In some map data formats each map item is not necessarily stored or encoded using a consistent byte length. Instead, to save overall storage requirements, the map items can be stored as different byte length variables. In accordance with an embodiment, the system comprises a bit stream processor that provides a staging area for efficient reading and writing of map data, and also provides security for adjoining data portions that use different byte length variables. An input map or map data can be read into the system, and optionally written to an output map. As map data is read into the system, instead of reading it directly from disk storage to the display screen, which takes time, the bit stream processor places the map data in memory and reads it from there. As map data is written to the system for storage or output, the bit stream processor can cache the map data in the cache, and write it from there.

Claims

1. A system for providing efficient access to digital map data, comprising:

a computer having a fixed disk or other non-volatile storage device for storage and archival of data;

a memory or other software accessible medium for enabling retrieval and access to the data;

a cache for temporarily caching some of the data;

a set of map data stored on the computer storage device, that corresponds to a digital map and that has a plurality of map items defined therein, wherein the digital map has a first map data format in which each map item is not necessarily stored or encoded using a consistent byte length; and

a bit stream processor that performs the steps of,

while map data is being read by the system from the storage device to the memory, instead of reading it directly from disk storage to a display screen, places the map data in the memory and reads it from there, and

while the map data is subsequently by from the system to the storage device or another output, caches the map data in the cache and then writes it from the cache.

2. The system of claim 1 wherein to save overall storage requirements, the map items are stored as different byte length variables on the storage device.

3. The system of claim 1 wherein the bit stream processor provides a staging area for efficient reading and writing of map data, and also provides security for adjoining data portions that use different byte length variables.

4. The system of claim 1 wherein the bit stream processor allows an input map to be read into the system in the first map data format, and written to the output as a second or different map data format.

5. The system of claim 1 wherein the first map format is Public Sector Information (PSI) format.

6. The system of claim 5 wherein the Public Sector Information (PSI) format uses a stream of data items of various sizes from N=1 to N=32 bits and wherein the bit stream processor allows the reading and writing of N bits of data from and/or to the memory at any given bit position, without disturbing neighboring bits.

7. The system of claim 1 wherein the map data is stored on the storage device in a compressed format.

8. The system of claim 7 wherein digests the map data as it is read from the storage device, and stores the bit locations of various “

memory markers”

in the bit stream so that the system does not then need to start digesting the bit stream from the beginning to again determine where the area features start.

9. A method for providing efficient access to digital map data, comprising the steps of:

providing a computer having a fixed disk or other non-volatile storage device for storage and archival of data;

providing a memory or other software accessible medium for enabling retrieval and access to the data;

providing a cache for temporarily caching some of the data;

accessing a set of map data stored on the computer storage device, that corresponds to a digital map and that has a plurality of map items defined therein, wherein the digital map has a first map data format in which each map item is not necessarily stored or encoded using a consistent byte length; and

using a bit stream processor to performs the steps of,

while map data is being read by the system from the storage device to the memory, instead of reading it directly from disk storage to a display screen, places the map data in the memory and reads it from there, and

while the map data is subsequently by from the system to the storage device or another output, caches the map data in the cache and then writes it from the cache.

10. The method of claim 9 wherein to save overall storage requirements, the map items are stored as different byte length variables on the storage device.

11. The method of claim 9 wherein the bit stream processor provides a staging area for efficient reading and writing of map data, and also provides security for adjoining data portions that use different byte length variables.

12. The method of claim 9 wherein the bit stream processor allows an input map to be read into the system in the first map data format, and written to the output as a second or different map data format.

13. The method of claim 9 wherein the first map format is Public Sector Information (PSI) format.

15. The method of claim 9 wherein the map data is stored on the storage device in a compressed format.

16. The method of claim 15 wherein digests the map data as it is read from the storage device, and stores the bit locations of various “

memory markers”

in the bit stream so that the system does not then need to start digesting the bit stream from the beginning to again determine where the area features start.

14. The method of claim 14 wherein the Public Sector Information (PSI) format uses a stream of data items of various sizes from N=1 to N=32 bits and wherein the bit stream processor allows the reading and writing of N bits of data from and/or to the memory at any given bit position, without disturbing neighboring bits.