Gambit TUI : how to find a vertex coordinate ?

Cyril

I'm adding a new geometry to an old one with a parametric journal.

But before, I would like to find the "highest" point on the Yaxix [0 Ymax 0] on the basis geometry.

Does anybody knows how to check the Ycoordinate of each point ? I would like to use this kind of methodology:

Ycompar=0 and Xi=0

do for i=0 to the end (I don't know how to find the end yet!)

if Y(i)>Ycompar then Y(i)=Ycompar

return the name of vertex (x=0, y=ymax)

Any idea ? thanks !