qcnt

   'qcnt' RETURN 'w'|'n'|'p'
This keyword is used to define a new center-point or -node by pressing ”n” or ”p” when the mouse pointer is at the position of a node or a point.

It is also possible to measure distances between two pixels on the screen. Just press the key ”w” on the positions of the two pixels. The distance is calculated in the scale of the displayed geometry.