LineSegment for

From David Forrest:

This measurement program acts as a scale and protractor, measuring lengths and angles to the resolution of your digitizer.It works by drawing a line segment from pen-down to pen up, reporting the coordinates, their differences, and the distance and angle of the line.With a straightedge, you can use this software as a protractor, astrolabe, transit, or sextant; limited by your ingenuity and skill, of course.It also can be used to explore your digitizer, and see how points are used.