Well, it is accepted in the SI Brochure, and is widely used in countries that have been metric for a long time. The US should get busy ADOPTING metric and get over its "holier than thou" attitude on hectares, centimeters, etc. As for the 45000 km², I think the easiest way to envision that is to take the square root and say "how big of a square is that" whether or not the shape is square. The answer is about 212 km on a side. I don't think 4 500 000 ha would be an improvement; it is too large a number, too small a unit.
--- On Tue, 3/13/12, Paul Rittman <[email protected]> wrote: From: Paul Rittman <[email protected]> Subject: [USMA:51515] Hectare To: "U.S. Metric Association" <[email protected]> Date: Tuesday, March 13, 2012, 10:06 PM 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 (8th 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.
