"Steve B" wrote in message
.. .
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?

Steve

Heart surgery pending?
www.cabgbypasssurgery.com
Heart Surgery Survival Guide
Basically put, it's a map/blueprint measuring wheel just like this
http://www.draftingsteals.com/21928.html