Paul,
The hectare is alive and well and frequently used in the United States.
Some fields of endeavor that use it are forestry and agriculture. Yields
in terms of kilograms per hectare or cubic meters per hectare are common
in agricultural research articles, for example. Hectares are used in
geography, geology, and the above fields when the square meter would
require too large a numerical value and the square kilometer too small a
numerical value. Likewise, biological population studies sometimes use
the hectare ("217 nesting pairs of Eastern Bluebirds per hectare").
When asked by local folks how large my farm is here in Middle Tennessee,
I tell them "100 hectares". If they ask and press the point I tell them
that's 250 acres. Caving in or educating them about the similarity in
sizes? You be the judge.
The missing part is what makes the relationship between the hectare and
the square kilometer hard to recall. We should also be permitted to use
the are:
100 square meters in an are
100 ares in a hectare (think hecto-...are)
100 hectares in a square kilometer
By the way, an old name for the square meter was the stere (see some of
our 19th century documents in the U.S.).
Jim
--
James R. Frysinger
632 Stony Point Mountain Road
Doyle, TN 38559-3030
(C) 931.212.0267
(H) 931.657.3107
(F) 931.657.3108
On 2012-03-13 21:06, Paul Rittman wrote:
What do people on this mailing list think of the hectare? I looked up a
few posts that were several years old, and it appears that some were
for, some against. At first sight, it appeared to me a very convenient
form of land measurement, being about the area of two American football
fields put together (easy to visualize), and convenient for measuring
the size of most lots and estates. The other measurements, the square
meter and square kilometer, seemed to produce numbers that were too
large or too small, especially since Americans are used to evaluating
the size of estates in terms of fractions of an acre, or tens or
hundreds of acres (and very occasionally thousands and millions of acres).
Now, however, I’m having second thoughts. I recall in my reading of
metric advocates, at least one has proposed using only square meters and
square kilometers (and avoiding the hectare). The square /m/ and /km/
are a factor of a million apart from each other (making for easier
conversions), whereas the hectare is 10,000 square meters, and I always
forget how many hectares are in a square kilometer.
Introducing the hectare to Americans who are rather unfamiliar with the
metric system might give them one more term to use (and it loses the
simplicity of the metric system, in that it has the /hect-/ prefix, but
not the base unit); simply using square meters and square kilometers
would give them more practice in the units that are already more common.
The SI brochure (8^th edition) places it in the non-SI units that are
acceptable (see page 124, Table 6. Non-SI units accepted for use with
the International System of Units). On page 117, it seems to prefer the
square meter, saying nothing about the square kilometer (itself of
course being a multiple of the square meter).
So is what is the opinion here about the use of the hectare,
specifically in the United States? I realize that it is not common at
all in real estate, but my question is, is this a unit that should be
used when exposing people to the metric system? Or is this a unit that
should be abandoned? I’d say junk it, but I just hate using numbers that
are either incredibly small or incredibly large, for lots that are in
the ½ to 50 acre range, for instance.
Today I told my students about a large land grant in the American
colonial period of some 45,000 square kilometers. I wasn’t sure how they
would understand that, so I told them that this was essentially the
northern third of North Carolina. Still, I was wondering later on if
giving them the measurement in hectares would have been better.
