drawing parallel and perpendicular line to a straight line

Posted by Pierre Ciparisse on Jan 03, 2008; 2:51pm
URL: http://imagej.273.s1.nabble.com/drawing-parallel-and-perpendicular-line-to-a-straight-line-tp3697666.html

Hello,

I'm new to the list.
I'm looking for solution in analysing digital X-ray images of head profile (orthodontic calculations).
With ImageJ, i'm able to select points and calculate distance and angle. It works well.
But I also need to construct points from parallel and perpendicular lines.

My question is, how can I draw a 'straight line' parallel to an other, and how can I draw a perpendicular line to an other straight line?

(It's very easy with a ruler and a 'set squarre' on a Rx-slide and a light box but... I would prefer to work based on digital picture)

Any suggestion?

Thanks in advance.

CIP