G15 · Design Google Maps Routing & ETA G15 · 设计 Google Maps 路线与 ETA
Verified source经核实出处
Maps routing is public research (contraction hierarchies, etc.). Credibility A.
Key decisions关键决策
- **Contraction Hierarchies**: precompute shortcuts so runtime Dijkstra is 100x faster.**收缩层次（CH）**：预计算捷径，使运行时 Dijkstra 快 100x。
- **Live traffic layer**: edge weights updated every 60 s from fleet probes + user reports.**实时路况**：边权每 60 s 由车队/用户上报更新。
- **Learned ETA**: GNN/GBM predicts travel time from features.**学习式 ETA**：GNN/梯度提升由特征预测行驶时间。
- **Caching**: popular OD-pairs cached per hour bucket.**缓存**：热门 OD 对按小时桶缓存。
Follow-ups追问
- Multi-modal? separate graph per mode; union at transfer nodes.多模态？每模式独立图；换乘节点合并。