Comments on: How big is a hectare?

by: Colin Nicholson

Tue, 14 Oct 2008 05:25:52 +0000

Who needs to visualise an area of land anyway? If you are a farmer or surveyor you will soon learn to do it, anyone else can look it up on Google and measure it, or use a GPS and pace round it.

We are buying a house in Portugal, and had to convert the stated area in square metres into acres in order to be able to compare its value with that of land in the UK, which everyone I know values by the acre. We were surprised to discover from our Brazilian friends that they use acres as well, and on investigation so do many other countries, including Portugal. Seems the British established the units as they surveyed the World and it stuck.

Why we are in such a mad rush to convert to metric units that are impossible to visualise when we had units of measurement that related to quantities we are familiar with in bodily scale I don’t know - I know exactly how big a 6ftx4ft window is, but in millimetres? Give me a break! And when it comes to pressure, forget it. The other huge benefit of non-metric units is that it teaches people to calculate in different bases than 10, so their maths becomes much better. It is only engineers that like everything to be so neat and tidy, to suit their obsessive temperement.

[Mr Nicholson illustrates very well the refusal of some people to learn anything new or different or to adapt to the modern world. “Mad rush”? after 43 years?! - Ed]

by: John Rainsbury

Tue, 26 Aug 2008 08:36:27 +0000

As a member of a Borough Planning Committee, all applications are measured in hectares, prior to being elected a hectare was an alien concept to me however, as a Rugby fan I can easily picture the area and mentally apply this to the applications. This was of real assistance.

As for Trafalger Square, I did know this, but not having been to London, (I do not often venture abroad) I could not picture the area. Living in Rural North West an acre is well known.

by: Tim D

Fri, 15 Aug 2008 10:14:32 +0000

I think the real problem affecting take-up of the (new-fangled) hectare is that most people really have a problem estimating 100m in length.

In my experience the guess tends to fall far short of 100m, in the 50-80m range, so their estimate of a hectare would therefore be about 1/3 to 2/3 the area of the real thing.

The rugby pitch size estimate (above) helps me - but they tend to look much smaller on TV than in reality

by: Robin Paice

Fri, 09 May 2008 09:01:48 +0000

Jon Child really answers his own question. The actual dimensions of an acre are obscure and little known by the general public, and manipulating the data requires prodigious calculations (JC could have added that there are 640 acres in a square mile). Most people just know that an acre is a big piece of land, and that 6 acres are more than 5 acres. As a unit of measurement it is hopeless.

By contrast, as described in previous comments, 100 m X 100 m = 10 000 square metres (m2) = a hectare (ha), and 100 ha = a square kilometre (km2). Dead easy.

The size of a football pitch has not changed significantly for over a hundred years. For a first class match it is approximately 100 m x 70 m, or 7000 m2, whereas an acre is about 4000 m2.

by: Jon Child

Thu, 08 May 2008 15:41:02 +0000

What is the problem with an acre?
1 acre = 4840 sq yds = 1 chain (22yds or the length of a cricket pitch) * 1 furlong (220yds or 1/8th of a mile).
A football pitch used to be about 1 acre in size, but that seems to have changed with metrication.

by: Han Maenen

Fri, 07 Dec 2007 10:54:38 +0000

In many states of the USA a unit called ‘commercial acre’ may be used legally to sell land. It measures exactly 36 000 sq.ft compared to the statute acre of 43 560 sq.ft. It was invented by real estate agents and is supposed to be the portion of an acre after deduction of infrastructure. Legal con trick is a better expression. If you buy ‘100 acres’ of land in one of these states, you may be in for a nasty surprise, 9.
In the Middle Ages most fields in Britain and in mainland Europe were long and narrow and the acre was also based on it: four rods by one furlong. The word acre, not the unit, has survived in the German and Dutch speaking parts of Europe: an ‘akker’ is a field for growing crops. A farmer may have, for instance, 100 ha ‘akkerland’. And, by the way, Trafalgar Square in London measures 1 hectare.

by: Daniel Jackson

Fri, 23 Nov 2007 17:02:09 +0000

Actually the hectare is equal to one square hectometre (hm^2). Since the unit are and none of the other prefixes are commonly used with the are (other then hecto), then I think the are as a unit along with any multiple/sub-multiple of it should be deprecated.

If one is expressing an area, it is best to just express it as A m x B m. This gives a better visualization of the lay of the land. One of the handy uses of square units is when pricing (currency unit per area). In that case, then the unit should be square metres or any prefix attached to square metres to put the numbers in the appropriate range.

The are and its prefixes, like the litre are not a part of SI and should not be promoted.

by: David

Thu, 22 Nov 2007 17:25:20 +0000

Although I know that an acre is approx 4000 m², when people say they want an acre of land, do they really know what that is, in terms of just how big it looks? I really cannot picture things in acres, although if it is 2.5 acres that is 1 hectare.
Hectare is a derived unit. The hect prefix means 100, and the unit is the “are” (pronounced like “air”). A bit of a strange word for area in English as it is the same word as “are” (from the verb “to be”, pronounced like “ahhr”).
So 1 hectare = 100 ares
1 are = 100 m²
The “are” is not used much in English, if at all, probably because of its unusual spelling.
Hectare could be used as very few other metric units used today are used with the hect- prefix, although things like hectometre, meaning 100 metres, are valid for use in metric. Also loose food items are often priced per 100 g, but that could be written as per hectogram (hg).
The hectare is preferable to the acre, as it relates more closely to a unit length (i.e. the metre) whereas no one seems to know what an acre is in relation to any imperial unit.

by: Roddy Urquhart

Wed, 21 Nov 2007 22:15:17 +0000

I am astonished that in the UK we have not embraced the hectare. Almost everybody talks about acres without having a clear idea of what they are. OK, if a house is for sale with an acre of land people would rightly realise that it was much larger than average. However, they would not appreciate the size in the sense of knowing what a metre or a litre or a foot is.

Having been brought up with Ordnance Survey maps and the one kilometre-based National Grid it is easy to visualise hectares on maps. A hectare is a hundredth of an OS kilometre square. The central part of Trafalgar Square is roughly one hectare so a good reference point. I also like Martin’s example of an international rugby pitch.

An acre is based on an Anglo-Saxon strip field. I have never seen strip fields in this country so cannot accurately visualise it. It is a furlong by a chain and I have difficulty imagining what furlongs and chains are unless I convert into metres.

When looking into properties we should ask for plot areas in square metres or for larger ones in hectares. Strangely one place you will find hectares is in the property pages of Country Life where large properties are advertised.

by: Alex Bailey

Wed, 21 Nov 2007 11:54:17 +0000

In response to Daniel - perhaps if I sit and think about it the acre is easily understandable in metric, but it still remains the fact that the acre is based on a rectangle with uneven edges where the hectare is a nice clean 100 x 100.

That said, if you’re looking at sporting “fields” then you generally have a rectangle anyway. In the case of my favourite sport , (ice) hockey, the rink size generally used in the international game (not the NHL though) is 30 m x 60 m which is about 0.18 hectare - although that doesn’t take into account the rounded edges of the rink!