09159150 cites 5 patents.

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.

Title
Bitmap array for optimally distributing map data content to wireless communications devices
Application Number
13/935645
Publication Number
9159150 (B2)
Application Date
July 5, 2013
Publication Date
October 13, 2015
Inventor
Xiaming Xi
Kanata
CA
Eric Johnson
Ottawa
CA
Agent
Moffat & Co
Assignee
BlackBerry
CA
IPC
G06T 7/00
G09B 29/00
G01C 21/20
G01C 21/00
G06T 11/60
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