Geographic information data base engine
First Claim
1. A method to compress a geographic database and retrieve the compressed geographic data, the method comprising the steps of:
- selecting at least one layer of detailed descriptive data to be compressed from an original geographic database;
partitioning the layer into a chosen number of discrete geographic bounding boxes;
selecting a reference coordinate in at least one geographic bounding box to be used as a reference coordinate for all other coordinates in the respective bounding box;
converting a selected number of absolute coordinates in the bounding box to a new relative coordinate with respect to the reference coordinate;
wherein at least one new relative coordinate in the bounding box comprises fewer digits than its absolute coordinate; and
thereby forming a new compressed geographic database having fewer stored digits than the original geographic database.
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Accused Products
Abstract
A method to compress a very large original geographic database down to a manageable and economical size while preserving accuracy is herein described. Similarly, a method to quickly retrieve, decompress, and display data is herein described. An original geographic database is prepared for compression by dividing it into discrete regions called bounding boxes. The bounding boxes may be variable sized to improve accuracy and compression. Absolute map coordinate data is compressed by converting it to relative map coordinate data. Map files are named in a descriptive manner to allow determination of map file characteristics merely by inspecting the file name. Relative map coordinate data can be displayed without being converted to absolute map coordinate data. Alternately, relative map coordinate data may be quickly decompressed into absolute coordinate data. Retrieving compressed data is facilitated by forming view windows having adjacent load regions pre-decompressed and ready for user display.
32 Citations
32 Claims
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1. A method to compress a geographic database and retrieve the compressed geographic data, the method comprising the steps of:
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selecting at least one layer of detailed descriptive data to be compressed from an original geographic database; partitioning the layer into a chosen number of discrete geographic bounding boxes; selecting a reference coordinate in at least one geographic bounding box to be used as a reference coordinate for all other coordinates in the respective bounding box; converting a selected number of absolute coordinates in the bounding box to a new relative coordinate with respect to the reference coordinate; wherein at least one new relative coordinate in the bounding box comprises fewer digits than its absolute coordinate; and thereby forming a new compressed geographic database having fewer stored digits than the original geographic database. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A method of naming a compressed geographic database file, the method comprising the steps of:
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determining the geographic area represented by the geographic database file; determining the type of data contained within the geographic database file; determining the accuracy of the data contained within the geographic database file; and naming the geographic database file such that the geographic area represented by the geographic database file, the type of data contained within the geographic database file, and the accuracy of the data contained within the geographic database can be determined merely by inspecting the geographic database file name.
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32. A system for compressing a geographic database and retrieving the compressed geographic data, the system comprising:
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a means for selecting at least one layer of detailed descriptive data to be compressed from an original geographic database functioning to allow an user to choose one or more entity types of interest; a means for partitioning the selected layer into a chosen number of discrete geographic bounding boxes functioning to provide a reference grid for data compression; a means for selecting a reference coordinate in at least one geographic bounding box functioning to provide a reference coordinate for all other coordinates in the respective bounding box; a means for converting a selected number of absolute coordinates in the bounding box to a new relative coordinate with respect to the reference coordinate functioning to reduce the number of digits of the coordinates; and a means for forming a new compressed geographic database functioning to provide a compact map data source for mapping applications.
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Specification