Bitmap Array Map Data Distribution for Wireless Bandwidth Optimization
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Solution Overview
Problem
Current wireless communication devices face inefficiencies in distributing map data, as they transmit excessive detailed vector data, especially at high zoom levels, which burdens wireless bandwidth and provides unnecessary detail, leading to user confusion and increased data transmission.
Innovation Solution
The method involves processing vector map data using a bitmap array at the map server to determine which features to retain or suppress, generating a bitmap array for a specified zoom level, computing attributes to identify unnecessary features, and transmitting only the data for retained features, either in vector or bitmap format, thereby optimizing data transmission and conserving bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If all vector map data is transmitted to wireless devices, then complete map detail is provided, but wireless bandwidth is excessively burdened and data transmission volume increases
Solution Approach 1:
The patent extracts only the necessary map features for display at the current zoom level from the complete vector map data. The server analyzes the requested zoom level and area of interest, then selectively extracts only those map features (roads, buildings, landmarks) that are visible and relevant at that scale, excluding extraneous detailed features that would not be displayed anyway.
Solution Approach 2:
The patent applies different levels of detail to different regions of the map based on their importance and visibility at the current zoom level. Critical features like major roads and landmarks are transmitted with high detail, while less important features are either omitted or transmitted with reduced detail, creating a locally optimized data set for each region.
2Measurement precision
If high zoom level map data is transmitted, then detailed map features are provided, but unnecessary detail causes user confusion and overlapping features
Solution Approach 1:
The patent applies partial action by transmitting only the subset of map features that are necessary for the current view, rather than all available features. The server determines which features should be visible at the requested zoom level and transmits only those, avoiding the excessive transmission of all possible map data including features that would be too small or obscured to see.
Solution Approach 2:
The patent changes the parameter of feature selection based on zoom level. At higher zoom levels, fewer and more important features are transmitted, while at lower zoom levels, more features are included. The server dynamically adjusts which map features to include based on the requested zoom level and area of interest, optimizing the balance between detail and clarity.
Data Source
AI summary
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.