I want to know something very simple which is making my life very difficult at the moment. I have an EM map of a virus capsid and I would like to make various distance measurements.

I simply want to draw a strait line and measure it or place two points on the map and measure the distance between them.

I have read all your help files on this matter and I cannot make any sense out of the instructions

Can you help me out ?

Thankyou

Mr A.I