Question

I am in need to write a function in postgeresql/postgis to update m-value in point geometry like POINT(X,Y, Z, M). For X, Y and z values it could be done by transformation for example. But updating M-value is another story.

Does anyone know something on this issue?

Do we have such a function or similar?

Answer 1

Well, there is

ST_MakePoint(double precision x, double precision y, double precision z, double precision m);

So you could update you M value like this

UPDATE mytable
   SET the_geom = ST_MakePoint(ST_X(the_geom),ST_Y(the_geom),ST_Z(the_geom),99.99)