A planimeter is a mechanical instrument used to compute the area of a planar
region. Here are some examples.
Other Planimeter Web Sites
to Use A Planimeter
Historic Information & Photos of Antique Planimeters
The Museum of HP Calculators
-- Several good photos
Mathematics: The Planimeter
& Green's Theorem
Antique Dealers and Auctions That Often Have Planimeters
The Gemmary Antique Scientific Instruments
-- This is a great site with excellent photos
eBay Search for "planimeter" or click on "Antiques" and then "Science Instruments."
Companies Selling Modern Planimeters
It is not my intent to support any particular manufacturer or seller of
planimeters, only to illustrate that they are still being made.
Modern electronic planimeters are typically expensive, however, in my opinion, the electronics
are illusory. They are mechanically the same as their non-electronic ancestors,
just with a calculator riding piggyback. The scale is read electronically, and
the results can be read out in square inches, square centimeters, or (based on
the scale of a map) square miles. Some also measure the perimeter of the region.
They are not noticeably more accurate, since their accuracy lies in
the skill of the operator, not in the electronics.
Try using one of the web search engines to search for "planimeter."
You will get lots of "hits," most of which will illustrate the variety
of ways planimeters are used in science, technology, medicine, archeology,
and many more areas.
Last update 24 August 2007