I don't know about modifying a monitor, but I do know about the math to do it in software...

To convert a polar coordinate to cartesian form, use the following formulae:
X= R*cos(Theta)
Y= R*sin(Theta)
R being the radius from the polar origin and theta being the angle to that point.

To make a sweeping line, just set R equal to some constant for the length and calculate how much theta should change each frame for the speed you want the line to rotate. Connect (r,theta) to the origin and there's your sweeping line. This can definitely be done in software, and my guess is it's easier to do that than deal with the monitor itself (Safer, too). I don't know how you might want to drive the screen, whether you want to write your own display driver or use an existing circuit. If the former is true, check out the following site as a starting point for VGA and SVGA timing.
http://www.epanorama.net/documents/pc/vga_timing.html

Good luck!

-Tony




> If anyone has modified a monitor sweep so that it functions as a radar screen please let me know.  I need to present intensity levels at polar coordinates, i.e., angle and radius vector.  Therefore a sweeping rotating line with 0.0 at the center of the monitor would be useful.
>
> If this could be done in software so that hardware
> modification to the monitor is not necessary, it would be much better.
>
> Regards,
> Richard

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