Mapping uncertain geometries to graticules
First Claim
1. A method for covering an uncertain geometry by a plurality of bounding boxes, the method comprising:
- obtaining, by a processor, data identifying a radius of a circle corresponding to the uncertain geometry;
obtaining, by the processor, data identifying a point at which the uncertain geometry is centered;
obtaining, by the processor, data identifying a latitude circle radius associated with a latitude of the point at which the uncertain geometry is centered; and
determining, by the processor, a resolution of the bounding boxes, wherein the resolution of the bounding boxes is determined by;
determining a number of bits of a geohash in a latitude dimension at the latitude of the point at which the uncertain geometry is centered;
determining a number of bits in the geohash in a longitude dimension at the latitude of the point at which the uncertain geometry is centered;
determining a bit length of the geohash by adding the number of bits in the latitude dimension of the geohash with the number of bits in the longitude dimension of the geohash; and
dividing, by the processor, the latitude circle into 2N segments, where N is equal to the bit length of the geohash.
1 Assignment
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Accused Products
Abstract
A geohash based cover for a geometry whose uncertainty is described as a circle with center point and a radius is disclosed. In one example, a geohash cover is computed that does not require any expensive geodesic calculations, providing roughly an order of magnitude improvement in speed up of cover calculation. In another example, distance computations are exact compared to a conventional process. In another example, the geohashes returned by the technique can vary between 4 to 9—with a median 6 (a certain conventional process would always return 9 hashes (all the 8 neighbors and the self geohash)). In another example, results are accurate, while still avoiding expensive geodesic computations.
32 Citations
20 Claims
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1. A method for covering an uncertain geometry by a plurality of bounding boxes, the method comprising:
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obtaining, by a processor, data identifying a radius of a circle corresponding to the uncertain geometry; obtaining, by the processor, data identifying a point at which the uncertain geometry is centered; obtaining, by the processor, data identifying a latitude circle radius associated with a latitude of the point at which the uncertain geometry is centered; and determining, by the processor, a resolution of the bounding boxes, wherein the resolution of the bounding boxes is determined by; determining a number of bits of a geohash in a latitude dimension at the latitude of the point at which the uncertain geometry is centered; determining a number of bits in the geohash in a longitude dimension at the latitude of the point at which the uncertain geometry is centered; determining a bit length of the geohash by adding the number of bits in the latitude dimension of the geohash with the number of bits in the longitude dimension of the geohash; and dividing, by the processor, the latitude circle into 2N segments, where N is equal to the bit length of the geohash. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A computer program product comprising a non-transitory computer readable storage medium, tangibly embodying a program of instructions executable by the computer for performing a method of covering an uncertain geometry by a plurality of bounding boxes, the program of instructions, when executing, configure the computer to perform:
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obtaining data identifying a radius of a circle corresponding to the uncertain geometry; obtaining data identifying a point at which the uncertain geometry is centered; obtaining data identifying a latitude circle radius associated with a latitude of the point at which the uncertain geometry is centered; and determining a resolution of the bounding boxes, wherein the resolution of the bounding boxes is determined by; determining a number of bits of a geohash in a latitude dimension at the latitude of the point at which the uncertain geometry is centered; determining a number of bits in the geohash in a longitude dimension at the latitude of the point at which the uncertain geometry is centered; determining a bit length of the geohash by adding the number of bits in the latitude dimension of the geohash with the number of bits in the longitude dimension of the geohash; and dividing the latitude circle into 2N segments, where N is equal to the bit length of the geohash. - View Dependent Claims (16, 17)
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18. A computer-implemented system for covering an uncertain geometry by a plurality of bounding boxes, the system comprising:
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a memory storage device; a hardware processor coupled to said memory storage device and configured to; obtain data identifying a radius of a circle corresponding to the uncertain geometry; obtain data identifying a point at which the uncertain geometry is centered; obtain data identifying a latitude circle radius associated with a latitude of the point at which the uncertain geometry is centered; and determine a resolution of the bounding boxes, wherein to determine the resolution of the bounding boxes, said hardware processor is further configured to; determine a number of bits of a geohash in a latitude dimension at the latitude of the point at which the uncertain geometry is centered; determine a number of bits in the geohash in a longitude dimension at the latitude of the point at which the uncertain geometry is centered; determine a bit length of the geohash by adding the number of bits in the latitude dimension of the geohash with the number of bits in the longitude dimension of the geohash; and divide the latitude circle into 2N segments, where N is equal to the bit length of the geohash. - View Dependent Claims (19, 20)
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Specification