Map Tile Road Compression via Segment Grouping
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Solution Overview
Problem
The existing methods for displaying road networks on mobile devices face challenges with large map tiles, particularly at middle zoom levels, which result in high data sizes, network throughput throttling, and processor rendering issues, due to the inclusion of detailed information that is not necessary for human visualization at a macro scale.
Innovation Solution
The system compresses road information by grouping road segments based on classification, combining them into paths, and using representative segments to define these paths in map tiles, reducing data size without sacrificing discernible accuracy, and approximating path locations based on zoom levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detailed road information is included in map tiles at middle zoom levels, then the accuracy and completeness of road network display is improved, but the data size of map tiles increases significantly
Solution Approach 1:
The patent segments the road network into multiple classification groups (e.g., highways, major roads, minor roads) and processes each group separately. This allows selective compression where different road classes are compressed to different degrees based on their visual importance, reducing overall data size while preserving accuracy for prominent roads.
Solution Approach 2:
The patent merges multiple road segments of the same classification into consolidated path representations. Instead of storing each individual road segment separately, collinear or near-collinear segments are merged into single path objects with shared geometry, significantly reducing redundancy in the data structure.
2Measurement precision
If map tiles at middle zoom levels contain comprehensive road information, then the visual accuracy is improved, but the network throughput is throttled due to large data sizes
Solution Approach 1:
The patent changes the data representation parameters by transitioning from storing detailed individual road segment attributes to storing consolidated path representations with fewer, more efficient attributes. This parameter transformation reduces the amount of data that needs to be transmitted while maintaining visual fidelity at the target zoom level.
3Reliability
If detailed road segments are stored in map tiles, then the rendering completeness is improved, but the processor rendering performance deteriorates
Solution Approach 1:
The patent merges multiple road segments into consolidated path objects that can be rendered as single graphical entities. This reduction in the number of renderable objects decreases the computational burden on the processor while maintaining the visual completeness of the road network through intelligent path construction.
4Quantity of substance
If road segments are compressed by grouping and using representative segments, then the data size is reduced, but the complexity of the compression process increases
Solution Approach 1:
The patent applies different compression strategies to different road classifications based on their local characteristics and visual importance. High-priority roads (e.g., highways) receive less aggressive compression to maintain quality, while lower-priority roads undergo more aggressive compression, optimizing the balance between data size reduction and visual accuracy.
Data Source
AI summary
Road information is compressed for map tiles of a map containing a network of roads. The map can have different sets of tiles for each zoom level. For a given zoom level, road segments can be grouped based on the class of the roads (e.g., interstate highway, state highway, divided highway, side street, etc.). The road segments of a particular class can be combined into paths, and a representative segment can be chosen for each path. The features of the representative segment can be used in displaying the corresponding path, thereby reducing the size used to store the path in a map tile. This reduce-size map tile can be transmitted more efficiently due to the smaller size.