APPARATUS AND METHODS FOR REDUCING DATA TRANSMISSION IN WIRELESS CLIENT-SERVER NAVIGATION SYSTEMS
First Claim
1. A method of reducing data transmission in a wireless client-server navigation system, comprising the steps of:
- receiving, at a central server, a request for data representative of a map-related feature from a mobile unit;
obtaining data describing the feature in the form of line segments interconnecting points having coordinates;
performing an operation on the data describing the feature to generate data representative of the feature in a data-reduced format; and
forwarding the data representative of the feature in the data-reduced format to the mobile unit issuing the request.
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Accused Products
Abstract
Methods and apparatus reduce data transmission in a wireless client-server navigation system. A request for data representative of a map-related feature is received at a central server from a mobile unit. Data describing the feature is obtained in the form of line segments interconnecting points having coordinates such as a shapefile or other format. An operation is performed on the data describing the feature to generate data representative of the feature in a data-reduced format, and the data representative of the feature in the data-reduced format is forwarded to the mobile unit issuing the request. The operation responsible for producing the data-reduced format includes the steps of: receiving data describing a map; partitioning the map into a plurality of tiles; designating a reference point within each tile; representing the feature in the form of offsets from the reference points; and wherein the data-reduced format is based upon the reference points and offsets. Alternatively, the operation may include the steps of approximating the feature with a curve, whereby the data-reduced format includes a description of the curve. In a further alternative embodiment, the operation includes the steps of removing one or more of the points having the coordinates, leaving a plurality of remaining points describing the feature, such that the reduced-data format is represented with line segments interconnecting the remaining points. In all embodiments, the operation may include, alone or in combination with other embodiments, the step of applying a data-compression algorithm to the data representative of the feature in the data-reduced format prior to forwarding the data to the mobile unit issuing the request.
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Citations
40 Claims
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1. A method of reducing data transmission in a wireless client-server navigation system, comprising the steps of:
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receiving, at a central server, a request for data representative of a map-related feature from a mobile unit; obtaining data describing the feature in the form of line segments interconnecting points having coordinates; performing an operation on the data describing the feature to generate data representative of the feature in a data-reduced format; and forwarding the data representative of the feature in the data-reduced format to the mobile unit issuing the request. - 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)
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26. A wireless client-server navigation system, comprising:
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a mobile unit including; a wireless transmitter for transmitting a request for data representative of a map-related feature, a receiver for receiving the data representative of the map-related feature, and a display for displaying the feature on a map; and a central server including; an input for receiving data describing map-related features in the form of line segments interconnecting points having coordinates, a receiver for receiving the request from the mobile unit, a processor for performing an operation on the data describing the map-related feature associated with the request by the mobile to generate data representative of the feature in a data-reduced format; and a transmitter for transmitting the data representative of the feature in the data-reduced format to the mobile unit. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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Specification