measuring angles with straight line tool

[Jordan Mallon]

I use the straight line tool in ImageJ quite regularly to measure
angles. I am frustrated, though, that I cannot control the baseline
from which to measure the angles. A straight line drawn towards the
right (i.e., 3 o'clock) yields 0 degrees; a line drawn upwards (12
o'clock) yields 90 degrees; a line to the left ( 9 o'clock) yields 180
degrees; and a line drawn downwards (6 o'clock) yields -90 degrees. Is
there an easy way to change the settings in ImageJ so that I can set
the 0 degree baseline, say, at 12 o'clock? And is it possible to
adjust the scale of measurement to yield positive angles only (so
that, say, -90 = 270 degrees)?
Thanks,

Jordan

[Gabriel Landini]

On Monday 06 April 2009 02:08:15 Jordan Mallon wrote:
> I use the straight line tool in ImageJ quite regularly to measure
> angles. I am frustrated, though, that I cannot control the baseline
> from which to measure the angles.

Maybe that's because you are using the wrong tool to measure angles.

What about using the Angle tool, which is the next button on the right...
There is extensive documentation on the tools here:
http://rsb.info.nih.gov/ij/docs/tools.html

G.