Crucially, this distribution of border points is agnostic of routing speed profiles. It’s based only on whether a road is passable or not. This means the same set of clusters and border points can be used for all car routing profiles (default, shortest, fuel-efficient) and all bicycle profiles (default, prefer flat terrain, etc.). Only the travel time/cost values of the shortcuts between these points change based on the profile. This is a massive factor in keeping storage down – map data only increased by about 0.5% per profile to store this HH-Routing structure!
Нина Ташевская (Редактор отдела «Среда обитания»)
。关于这个话题，Line官方版本下载提供了深入分析
It is designed to fill the operational gap between simple chroot
const circle = new Circle({ radius: 1.5 });