How to calculate x, y, z, m in Postgis

Question

Somebody know how can I calculate the x,y,z,m parameters from a MultiLineStringZM in Postgis?

I would like to know x,y,z and m from the points what are made the polyline.

When I try calculate it by this way "*st_x,st_y, st_z, st_m*" postgis go up an error message: ERROR: Argument to M() must be a point

Any idea?

Thanks,

JM

Answer 1

Try this function: http://postgis.net/docs/ST_DumpPoints.html

The rest should be straight forward (ST_X, etc).

I hope it works out for you!