Drainage - Valves

Point features represent drainage valves along the city's drainage network including types such gate, backflow preventer, and air release valve. Valves are used to regulate flow in the drainage network. Updated as an ongoing process.点要素（Point features）指代城市排水管网沿线的排水阀门，涵盖闸阀、防回流阀及排气阀等类型。此类阀门用于调控排水管网内的流体流量，本数据集处于持续更新的进程中。