Hi Pat et al,
Your example of using millimeters for buildings and manufacturing helps to
make my point. To convert to metres you just insert a decimal point or drop
least significant digits to make the numbers smaller for less precision. This
has nothing to do with accuracy of the original measurement, only in reporting.
This makes my point for simplification.
No fractions are suggested although a decimal point could be used for
reporting purposes. House lots in the US are given in square feet and farms in
acres. Eliminating hectares eliminates an unnecessary specialized unit like
eliminating acres would be in the US. Staying with base or decimal units would
be simplification.
Regards, Stan Doore
----- Original Message -----
From: Pat Naughtin
To: U.S. Metric Association
Cc: U.S. Metric Association
Sent: Thursday, February 12, 2009 7:55 PM
Subject: [USMA:42986] Re: hectare in a fire
Dear All,
Recently I referred to the fact that the size of bush fires bush fires are
estimated and reported in hectares in Australia. In response:
On 2009/02/11, at 11:06 AM, STANLEY DOORE wrote:
Hi Pat et al:
Thanks Pat for the fires update. The fires there are getting TV time
here in the US.
This would be a good example of simplification if square kilometres was
used instead of hectares. km^2 would be so much more understandable, useful
and would require much less computation, especially those of us in the United
States who are converting to the SI.
Our prayers are with you all.
Regards, Stan Doore
The use of hectares works quite well for us in Australia. Basically, we use
three area units for routine reporting of area measurements and estimates:
square metres, hectares, and square kilometres.
* Residential land and house internal sizes are measured in square metres
* Farming land and bush fires are measured in hectares
* Mapping is done in square kilometres
These choices mean that all numerical reporting uses whole numbers without
any need for fractions at all. No common or vulgar fractions and no decimals.
Only specialists such as cartographers have a need to change from one level
of accuracy and precision to another. The public seems to quite happily just
jump from one frame of reference to the next without any need for conversion
algorithms or conversion factors. With respect, Stan, I think that this might
be what you are referring to when you say that square kilometres would be so
much more understandable. This might be the case if you are focused on doing
conversions but it is not relevant when no conversions are done or thought to
be necessary (except for specialists). Please note that Australians are used to
working in millimetres (only) for all buildings (from kitchen renovations to
multi-storey buildings) and almost all manufacturing, so Australian people are
quite used to working with large numbers.
Even though they probably are not conscious of the reason, Australians
benefit from the ease of working with whole numbers without fractions when they
are considering the measurement of area on various scales. As I said the use of
square metres, hectares, and square kilometres works pretty well for us.
By the way, while I am on the subject of measuring area, I can only think of
two examples where I have had a need to use square centimetres in the past 10
years. The first was when I wanted to estimate the mass of water in an
aquarium. I measured the length and width to calculate the area of the base in
square centimetres; and then used various depths of water in centimetres to
calculate the volume at the various levels in cubic centimetres. From this I
then calculated the mass of water using the idea that 1 cubic centimetre has a
mass of 1 gram. Schools use square centimetres and cubic centimetres quite
frequently, but I have not seen, or heard of them being used in any industrial
or commercial settings. Schools also calculate cubic decimetres as the basis
for the definition of a litre and for developing the relationship that a litre
of water has a mass of a kilogram, but again, I have rarely seen this idea used
in industry; the single example I can think of was for the estimation of the
volume of water in a wool washing bath.
Cheers,
Pat Naughtin
Geelong, Australia
----- Original Message -----
From: Pat Naughtin
To: U.S. Metric Association
Sent: Tuesday, February 10, 2009 5:36 PM
Subject: [USMA:42978] Re: hectare in a fire
Dear All,
The good news is that the temperatures have dropped markedly in the last
few days and forecasts are for similar lower temperatures, from the mid 20s to
the low 30s, for the next week. There are even a few areas that might have 5
millimetres to 10 millimetres in the next 24 hours. This will give the fire
fighters from our Country Fire Authority (CFA) a chance to first of all contain
and then to 'blacken' the fires that are still active. Wendy and I and our son,
his wife, and grandchildren are all fine and well out of the range of any of
the initial 200 fire outbreaks; the closest was about 70 kilometres away. Our
only family worry is that Wendy's sister and her family have a fruit orchard
and a vineyard in a valley near one of the major fires and they have been
immersed in smoke since Saturday; the worry is that the smoke will effect the
fruit and the grapes as some of these were almost ready for harvest.
Of these 200 original fires 11 of them were regarded as major fires and
the 'urgent' messages coming from the radio emergency service were more or less
continuous through 24 hours of the day. Currently we still have about 35 fire
locations that are still active and 3 of these are still major fires. There are
still 'urgent' messages and 'alert' messages being issued from the CFA on a
regular basis. Senior fire officers are now delivering hopeful messages of
confidence that they will be able to control the remaining fires within the
next week or two. As usual our CFA has done a fantastic job. As have all of our
other community groups who have supported the work of the fire fighters. People
like the Country Women's Association (CWA), who suddenly turn up at remote
locations in the middle of the bush on the edge of a major fires with
generators for electricity, urns to boil water for tea and coffee, and the
wherewithal for making thousands of sandwiches to give the fire fighters
sustenance during the meal breaks that can happen at any time of day or night.
Could I suggest that you tune to the streaming radio station of the
Australian Broadcasting Commission (ABC). This is a government radio station
that normally broadcasts popular music and talk-back radio on political and
legal issues, but when we have bush fires it changes to our emergency radio
service. You will find this radio service at http://www.abc.net.au/melbourne
and the reason I am suggesting that you do this is so that you can appreciate
at a personal level the outpouring of support that has not only come from
ordinary people in the Australian community but also from the international
community. The stories that you will hear will amaze and inspire you. I feel
immensely proud to be part of the community of Victoria at this sad time.
As you probably know, the CFA of the state of Victoria has very good
relationships with the states of California and Washington in the USA. It is
not unusual for fire fighters from California and Washington to come here to
help us with extended fires and for some of our 'fireys' to help out in the USA.
Another feature of this emergency fire service is that the reports from
ordinary citizens are invariably given in metric units. It has been the policy
of fire fighters here to use metric units since the 1970s and the stated reason
for this was fire fighters' safety. In the Rural Fire Service (RFS) of the
state of New South Wales it has been a 'reportable offence' to use old
pre-metric measures at a fire location since the early 1970s. It took longer
for the general community to adopt this practice but this in now widely
accepted.
Cheers,
Pat Naughtin
Geelong, Australia
On 2009/02/08, at 11:18 AM, Pat Naughtin wrote:
Dear All,
As I advised yesterday we were in for a hot dry day with low humidity
yesterday; the prediction was for 44 °C. It turned out that the temperature at
the Avalon airport near Geelong was the hottest place in the state. The
temperature there reached 46.9°C at 15:00 with winds gusting between 10 km/h
and 60 km/h. See http://www.bom.gov.au/products/IDV60801/IDV60801.94854.shtml
Fortunately for us there were no bush fires within 50 kilometres of
Geelong, but more than 200 fires were reported from other parts of the state of
Victoria — 11 of these are regarded as major fires burning areas of up to 30
000 hectares — these fires are still active.
One of the government owned radio stations (Australian Broadcasting
Commission or ABC 774) becomes an emergency information service under these
circumstances. You can listen to a streaming of this service from
http://www.abc.net.au/melbourne where you will notice that almost all
dimensions supplied use metric units including hectares for the size of fires.
The exceptions come from some few people who phone in to the talk-back
components. The fire services have, since the 1970s, regarded using old
pre-metric measures as a reportable offence since it puts volunteer fire
fighters lives at risk to use multiple methods of measurement. I think that the
ABC does an excellent job of providing this emergency bush fire information -
you might like to listen for a while to see how we manage this kind of service
in Australia.
By the way, as I listen to the radio, I think of hectares like this:
1 I hear of a fire that is estimated as 165 hectares
2 I take the square root of the number: sqrt (165) = 13 (approx.)
3 Multiply 13 by 100 = 1300 metres.
4 I think of this is a fire that, as a square, would be about 1.3
kilometres by 1.3 kilometres.
Let me repeat this for one of the larger fire that is estimated to be
30 000 hectares
1 I hear of a fire that is estimated as 30 000 hectares
2 I take the square root of the number: sqrt (30 000) = 170 (approx.)
3 Multiply 170 by 100 = 17 000 metres.
4 I think of this is a fire that, as a square, would be about 17
kilometres by 17 kilometres.
A square in this particular case works well enough because these fires
were burning with north-westerly winds before a cool change arrived from the
south-west in such a way that one edge of some large fires changed to the front
of the fire. We are fortunate that the south-westerly change has meant that the
temperature today has dropped for the western half of the state to the mid 20s.
The lower temperatures mean higher humidity so these weather factors should be
helpful to the roughly 3000 mostly volunteer fire fighters.
Pat Naughtin
PO Box 305 Belmont 3216,
Geelong, Australia
Phone: 61 3 5241 2008
Metric system consultant, writer, and speaker, Pat Naughtin, has helped
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