On Apr 18, 10:18*am, bud-- wrote:
On 4/17/2011 4:54 PM, Steve B wrote:

I need one of those pen contraptions that you roll over blueprints and
aerial photos that then give a numerical value to the distance traveled..
What are they called, and what's a good supplier of them?

Try opisometer

That's a new word on it for me, but it looks like it is the most
accurate. Thanks for posting it.

R