TopoElement — 将拓扑几何转换为拓扑元素。
topoelement TopoElement(topogeometry topo);
这是一个完整的独立工作流程
Return the TopoElement representation of each topogeometry.
SELECT TopoElement(topo) FROM neighborhoods;
Use a cast to aggregate topogeometries into a TopoElementArray.
SELECT topology.TopoElementArray_Agg(topo::topoelement) FROM neighborhoods GROUP BY city;