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
The one I have is called a double readout plan measurer.
It's an opisometer. I have one kicking around that I used to use occasionally on maps when TSD rallying in the 1960s.
Jeffry Wisnia (W1BSV + Brass Rat '57 EE) The speed of light is 1.8*10e12 furlongs per fortnight.
Planimeter.
Or these things?
Best regards, Spehro Pefhany
You are right, Sphero. A planimeter measures AREA inside the curve.
Uh, the OP didn't ask for area, he asked for distance traveled...
Jeff
Jeffry Wisnia (W1BSV + Brass Rat '57 EE) The speed of light is 1.8*10e12 furlongs per fortnight.
Almost bought one at A&M but refrained since it was only a hobby toy.
K&E sold them.
Search for engineering supply store. Maybe K&E.
Mart> Steve B wrote:
Good question. I think mine is made by Phillips, got it from a relative that worked for the italian goverment railroad. I never found out what it was called.
"jeff_wisnia" wrote
I specifically need it to measure random lengths of wavy sidewalks in aerial photos of HOAs.
Steve
There will be a scale somewhere, read it, then measure the length with a ruler and do the maths. Easy as. And I think, from fading memory, the thing you need is only a few bucks at most outdoor/camping stores.....(it does make life a lot easier, those things) Plastic stuff - dont stress about Quality.
Andrew VK3BFA
You average it, then 10% if your estimating for P&P, or cable. Unless your prepared to walk it, which is pointless as the P&P guys will ALWAYS got for straight lines...even linear is pretty OK, you know the guys who do the actual work will regard your plans as but a General Indication of what you want done.......
P&P =3D Pit and Pipe guys - the real pointy end. Guys who dig trenches and lay conduit. No stuffing around. Just Do It. See someone direct a bore through a hill, is good - real skill. A backhoe operator who could do 1/4 inch cuts - thats skill. These are the real heroes, not some idiot Actor or Sportsman, this is real people doing real things, and doing it well. I respect that. So should you. Stuff the politics crap.
Andrew VK3BFA.
Did you have Prof. Adams for mechanical drawing?
Dan
Wouldn't it be easier to digitally expand the pic and count the 3' squares, Steve? How many of these do you have to do? And you'll still have to give the picture a scale so the osiometer will give you a valid number. Tough job.
-- If only he'd wash his neck, I'd wring it. -- John Sparrow
Can't remember that name...
These days I'm lucky if I remember to zip up my fly 50% of the time.
When it gets so bad that I forget to unzip it before I pee I'll know it's time to quit.
Jeff
That would be easy here. I'd scan the photo, import it into Design Cad, trace the line and read the length of the line...
Planimeter measures area; for straight-line distance on a map, you'd use a ruler, of course. For curves, I'd bend a spline to match the curve, and flex a tape measure onto the spline, because I don't have a suitable other gizmo.
And at the top end of these gizmos, there's a gadget that's called a harmonic analyzer, that uses a polar planimeter as its output device, that does a one-component Fourier analysis. Tide tables of the 1940 vintage would have some connection with their use.
You've heard the (very) old one about the absent-minded guy that unbuttoned his vest, pulled out his tie and peed himself?
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