BITMAP ARRAY FOR OPTIMALLY DISTRIBUTING MAP DATA CONTENT TO WIRELESS COMMUNICATIONS DEVICES
First Claim
1. A method of distributing map data from a map server to a wireless communications device, the method comprising steps of:
- obtaining vector map data in response to a request for map data received at the map server from the wireless communications device;
generating a bitmap array representative of the vector map data for a particular location specified in the request;
computing attributes of the bitmap array to determine which map features are to be retained and which map features are to be omitted; and
transmitting to the wireless communications device only the map data for the map features to be retained.
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Accused Products
Abstract
A method of distributing map data from a map server to a wireless communications device entails generating a bitmap array representative of the vector map data for a given zoom level, computing attributes of the bitmap array to determine which map features to retain and which map features to suppress, and then transmitting to the wireless device only the map data for the map features to be retained. By counting the number of bitmap cells representing a polygonal map feature such as a park, lake, or island, the approximate area is quickly estimated. If the area falls below a threshold, the map data for the small polygon is discarded. Similarly, if a polyline map feature overlaps (or is too proximate to) another polyline map feature, one of the polyline map features is discarded. The map data actually transmitted is thus reduced, thereby economizing bandwidth without unduly sacrificing map detail.
65 Citations
28 Claims
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1. A method of distributing map data from a map server to a wireless communications device, the method comprising steps of:
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obtaining vector map data in response to a request for map data received at the map server from the wireless communications device; generating a bitmap array representative of the vector map data for a particular location specified in the request; computing attributes of the bitmap array to determine which map features are to be retained and which map features are to be omitted; and transmitting to the wireless communications device only the map data for the map features to be retained. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A computer program product comprising code which, when loaded into memory and executed on a processor of a map server, is adapted to perform the steps of:
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obtaining vector map data in response to a request for map data received at the map server from the wireless communications device; generating a bitmap array representative of the vector map data for a zoom level specified in the request; computing attributes of the bitmap array to determine which map features are to be retained and which map features are to be omitted; and transmitting to the wireless communications device only the map data for the map features to be retained. - View Dependent Claims (14, 15, 16)
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17. A map server for distributing map data to the wireless communications devices, the server comprising:
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a data port for receiving a request from the wireless communications device for map data; and a processor coupled to memory to; process the request and obtain vector map data in response to the request for map data; generate a bitmap array representative of the vector map data for a zoom level specified in the request; compute attributes of the bitmap array to determine which map features are to be retained and which map features are to be omitted; and transmit to the wireless communications device, via the data port, only the map data for the map features to be retained. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A wireless communications device comprising:
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an input device for enabling a user to request map data; a processor coupled to memory for communicating a request to a map server; and a display for displaying a map rendered from map data received from the map server, the map server transmitting only the map data associated with map features that are to be retained after processing the map data using a bitmap array from which attributes of the map features are computed in order to determine whether to retain or omit map features.
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28. A method of processing vector map data in a map server, the method comprising steps of:
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generating a bitmap array representative of the vector map data for a particular location specified in a request for map data received by the map server; computing attributes of the bitmap array to determine which map features are to be retained and which map features are to be omitted; and making available for transmission to a wireless communications device only the map data for the map features to be retained.
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Specification