Planimeter?????

[Mark Rios]

What is this tool used for? What does it measure?

http://www.amazon.com/gp/product/B0007SXGG0/qid=1152035378/sr=1-16/ref=sr_1_16/104-3173667-8997509?%5Fencoding=UTF8&s=hi&v=glance&n=228013

This has a "single function" designation. Does that mean that there's a "multi function" planimeter?

This looked intriguing. I don't know what I'd do with it, even if I knew what it was, but it looked interesting.

[Bruce Page]

Beats the heck out of me.:confused:
The company seems to specialize in surveying equipment though.

[Vaughn McMillan]

Mark, a planimeter is a drafting instrument used for measuring area. Dunno how they're used, and I haven't seen one for eons, but I'd imagine they're not real common now in the day and age of CAD and ither computer tools.

- Vaughn

[Jake Helmboldt]

http://en.wikipedia.org/wiki/Planimeter

planimetrics or planimetric data refers to two-dimensional mapping of geographic features but I've not known of anyone using a planimeter for mapping (that is usually done w/ a digitizer or directly from a computer).

[Bob Michaels]

A planimeter measures distances on scaled drawings. You would run the smaller knob along a line on a drawing to get the length. The real advantage is when doing takeoffs for estimating. For instance, if you wanted to estimate how lineal feet of crown moulding are required in say 10 rooms, you would run the stylus of the planimeter around the floor plan on the scaled drawing, jumping from one room to the next, and the result will be the total LF.

[Ben Grunow]

In civil engineering (at Union College) we used a planimeter to find the interior area of an incongruous shape such as a plot of land or a kidney bean shaped swimming pool. A scale is entered and one arms pivot point held while the other traces the outline of the shape (you use your hand to manually follow the line around). When done the planimeter will calculate the interior area for you.

These are traditionally used for inexact calculations where the answer youre after is a rough number not precise down to the decimal because by the time you scale something down to fit on a drawing and then trace it by hand you have created too much error for an accurate figure.

[Roger Bell]

Until computers came along, we used them to calculate the average end area of a road prism....to "bug" quantities of earthwork. After hand drafting your cross sections of the road, you run the planimeter three times over the cross section and average it out. From that you calculate your cuts and fills and balance out the earthwork to the extent practicable. They are as accurate as your survey (or "data in")....just like computer programs are now.