Hectares for Dummies

hectare to acre

Since so many of the staffers here at the Antisocial Network have a science background, it stands to reason that many of them are careful about accuracy when it comes to numbers, especially conversion factors. It is our experience, however, that many freelance writers with a... "creative writing" background are less interested in accuracy and more interested in style. That may be why eHow.com became the laughingstock of the internet just before it was blitzed by Google's Panda II update. Be that as it may, a lot of their work survives, including the Sciencing.com post, "How to Calculate Hectares," created by Todd Whitesel.

Our first thought was, "Given a polygon whose sides are measured in meters, how do you calculate the area in hectares?" The answer is, of course, pretty simple; given that a hectare is defined as 10,000 square meters (m²).

That's what we thought. It wasn't what Whitesel thought, though. No,. right out of the box, Todd decided we wanted to convert from imperial units to hectares. His numbers, however, suffered from... inaccuracy; as did his very definition of a hectare:

"A hectare is a metric unit for measuring area, with one hectare equaling 2.471 acres or 10,000 meters. [sic]."

Todd seems to have forgotten that a hectare is a measure of area and a meter is a measure of length... oops. He went on to inform his readers that,

"...an American football field, including end zones, measures 0.535 hectares..."

Which is essentially true. Baseless in this case, but true. Of course, if Whitesel were to use the conversion factors he threw up at eHow.com, he wouldn't get that number. According to Whitesel,

"1 acre = 43,500 square feet"

Given that a (NFL) field measures 57,500 square feet and the conversion factor from acres to hectares is 2.47105, the calculation goes something like this:

(57500 / 43500) / 2.471 = 0.535

Todd's problem? The dumbass gave the wrong conversion factor for ft²/acre: it's 43,560, fool! The calculation might come out "close enough" for a football field when rounded to 3 decimal places, but what about a square mile (640 acres)? Let's try it with larger numbers:

((5280 * 5280) / 43500)  / 2.471 = 259.36

((5280 * 5280) / 43560)  / 2.471 = 259.00

It may not seem like much, but if you're paying $10,000 per hectare, you just cost someone $3600.
Whitesel blathered briefly about converting square feet and square yards to acres before converting the acreage to hectares, but must have been frightened by the exponents in the direct conversion factors. For the record, a hectare is 11,959.9 square yards and 107,639 square feet....

...not that our Dumbass of the Day ever seems to have thought of direct conversions.

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