Return the spatiotemporal bounding box covering every materialised position in a set of network points. The aggregate is polymorphic with the extent aggregates on the other spatial temporal types, so one query can compute a single box across a heterogeneous set of tgeompoint, tgeometry, and tnpoint columns. Each instant's spatial extent is resolved through the ways registry, which dominates the cost over a large input.

extent(tnpoint) → stbox

SELECT extent(temp) FROM tbl_tnpoint;