1Boundary - open linestringM
2:memory: #use in-memory database
3SELECT AsText(Boundary(GeomFromText('LINESTRINGM(1 2 3, 4 -3 6, 2 -1 -4)')))
41 # rows (not including the header row)
51 # columns
6AsText(Boundary(GeomFromText('LINESTRINGM(1 2 3, 4 -3 6, 2 -1 -4)')))
7MULTIPOINT M(1 2 0, 2 -1 0)
8