Internally, the HD Live Map product integrates the Road Model, the Lane Model, and Localization Model.
Because NURBS-based implicit geometry is hard to derive and calculate quickly in a moving vehicle, and our customers have experience with 2D polylines but not 3D splines, we calculate all the geometries of NURBS and publish them as polylines organized into one lane group for each road surface path. Accessors are published as lane group connectors, and portals are published as lane connectors. As a result, published HD Live Map topology is mostly compatible with the Road Model — enriched with lanes, lane boundaries, and additional attributes.
This publication process supports multiple output formats. Currently, we support a proprietary Native format based on Protocol Buffer, which most closely resembles the source data. We also publish to the industry-standard NDS (Navigation Data Standard).
The publication process for HD Live Map generates catalogs containing assorted layers of map data in specific regions (e.g. North America, Western Europe, Asia, etc.). Within each region, map data is organized into rectangular tiles to facilitate incremental updates and delivery.