Knots are for boats!
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A yard is a meter!
Anyway, you have all got it completely wrong, Knots are for keeping Boy Scouts, Cubs, Brownies and Guides occupied when the Leader can't think of anything else for them to do.
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Originally Posted by Capot
I locate myself using latitude and longitude, and so does my GPS
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You are right; how could I have been so lax.
I meant to say "I locate myself using a pencil and a parallel ruler to mark a position on a chart showing latitude and longitude, while my GPS locates itself in Earth Centered, Earth Fixed Cartesian coordinates, using meters as a unit and then displaying its position in latitude and longitude entirely for my conveninece."
And then I would have checked my spelling, just to make sure I would escape all criticism, and corrected any errors that I noticed.
I meant to say "I locate myself using a pencil and a parallel ruler to mark a position on a chart showing latitude and longitude, while my GPS locates itself in Earth Centered, Earth Fixed Cartesian coordinates, using meters as a unit and then displaying its position in latitude and longitude entirely for my conveninece."
And then I would have checked my spelling, just to make sure I would escape all criticism, and corrected any errors that I noticed.
Capot could be right. Last I had a yard of ale, it was just 3'!
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There are 3 possibilities for what the yard was based on, and none of them encourages one to go on using it;
1. It's a double cubit. ("What's a cubit?" "Half a yard, stoopid".)
2. It was more or less the distance around a man's waist.
3 It was the distance from King Henry I (1100-1135)'s nose to his thumb, with his arm outstretched, or something like that. That's King Henry I of England, and some of France as I recall, perhaps wrongly.
The word 'yard' comes from the Old English gyrd, meaning a rod or measure
Enough already.
1. It's a double cubit. ("What's a cubit?" "Half a yard, stoopid".)
2. It was more or less the distance around a man's waist.
3 It was the distance from King Henry I (1100-1135)'s nose to his thumb, with his arm outstretched, or something like that. That's King Henry I of England, and some of France as I recall, perhaps wrongly.
The word 'yard' comes from the Old English gyrd, meaning a rod or measure
Enough already.
Last edited by Capot; 14th Jul 2012 at 14:04.
I'm with yotty on this. Fathoms. The original decimal system.
100 Fathoms = 1 cable. 10 Cables = 1 Nautical mile.
So, speed in knots, height in fathoms, vis in cables.
"XXX, you are cleared to descend to 300 fathoms, radar heading North North East by East, report established ILS for runway North West By North Port, RVR 1 cable."
What could be simpler?
100 Fathoms = 1 cable. 10 Cables = 1 Nautical mile.
So, speed in knots, height in fathoms, vis in cables.
"XXX, you are cleared to descend to 300 fathoms, radar heading North North East by East, report established ILS for runway North West By North Port, RVR 1 cable."
What could be simpler?
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Vessel speed at sea was measured using a chip log. This consisted of a wooden panel, weighted on one edge to float upright, and thus present substantial resistance to moving with respect to the water around it, attached by line to a reel. The chip log was "cast" over the stern of the moving vessel and the line allowed to pay out.
Knots placed at a distance of 47 feet 3 inches (14.4018 m) passed through a sailor's fingers, while another sailor used a 30 second sand-glass (28 second sand-glass is the current accepted timing) to time the operation.
The knot count would be reported and used in the sailing master's dead reckoning and navigation. This method gives a value for the knot of 20.25 in/s, or 1.85166 km/h. The difference from the modern definition is less than 0.02%.
there is the foundation of your measurement...
Knots placed at a distance of 47 feet 3 inches (14.4018 m) passed through a sailor's fingers, while another sailor used a 30 second sand-glass (28 second sand-glass is the current accepted timing) to time the operation.
The knot count would be reported and used in the sailing master's dead reckoning and navigation. This method gives a value for the knot of 20.25 in/s, or 1.85166 km/h. The difference from the modern definition is less than 0.02%.
there is the foundation of your measurement...
The metric system is the only way. The Russians are way ahead of us. Miles and knots are from the past. As are gallons, stones, yards, feet and inches.
The old Imperial system is on its last gasps, as it should be. Aviation is the last stubborn area where it's hanging on and I hope that it transitions as quickly as possible to full metric.
Though I would actually like to see Planck Units used, they make even more sense than Metric does.
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What about TIME: Could we please have a year equalling 1000 days with 10 months of a 100 days and a week of 10 days. The World wasn't built for metric units but for aesthetics where a pint of beer looks and feels right and is what an average person wants to consume in any one session. The same applies to weights: a pound of anything is much more to the human scale than kilograms etc. Packing is another problem much easier to pack a dozen items (3x4 or 2x6) than 10. And why isn't the World a perfect circle rather than an oblate ellipse? In the World of computers it's binary so 1s and 0s and thus bits, bytes hexadecimal octal .....
I think the ancient Egyptians first divided the day into 24 hours, 12 hours of day and 12 of darkness. But the base of 60 (for time and compass directions) came from the Babylonian system of counting which they may well have inherited from the Sumerians. Many of our current methods of counting and measurement come from very ancient roots! Rather than changing them let's glory in their antiquity. Also, 60 is quite convenient as it can be divided in many ways.
Last edited by Bergerie1; 15th Jul 2012 at 12:54.
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Originally Posted by fullwings
Not to mention millibars, hectopascals, inches and mm of mercury. All still in use today in aviation, somewhere in the world...
Last edited by A Squared; 15th Jul 2012 at 18:45.
Look folks - this is really simple.
Exactly 6,000 Years ago, the Creationistas say that we were made.
We were a bit confused, and so concentrated on our fingers and toes, and decided that base 10 could work.
We then discovered that the World was spherical-ish and created a flawed mapping system.
They saw that one could divide the oblate spheroid into segments, like the Oranges that they were enjoying when boiled with sugar and made into Marmalade.
Good result. It worked. But.
They didn't spot that Lines of Latitude might have been better replaced by choosing an East and West Pole and cutting the sphere into segments akin to those that Lines of Longitude do.
They would then have been able to work out the best way to eat a Grapefruit.
Notwithstanding this error, some bright spark realised that multiples of 12 offer more outcomes of subdivision than those of 10. Good point, and well made.
Then at some point (and I'd welcome some input from the Creationistas for an exact date) we noticed the stars and Sun/Moon/Planets, and made some notes. And with some sums worked a few things out so that we could guess our location.
A bit further along, Radio was created, (again, input welcomed) and some people (who turned not to be on our 'like' list) came up with "Ultrakurzwellen-Landefunkfeuer".
This was not good news.
But it was a turning point (sorry). Thereafter the electronic and radio based systems (with the exception of the simple RDF) relied on lines on maps for co-ordination which were entirely arbitrary. The 1980s gave us (civilians) electronics which would do their stuff and give us Lat/Long - but only thinking in 1/0s internally.
Today the gps system does not have a clue about units that we would use. They work out where we are and, in much the same way as we would say 'print' on some data, it stuffs it through the last bit of software to demonstrate some sort of recognisable position.
That, folks, is my take on the history of mapping.
Now if I could start.......
Exactly 6,000 Years ago, the Creationistas say that we were made.
We were a bit confused, and so concentrated on our fingers and toes, and decided that base 10 could work.
We then discovered that the World was spherical-ish and created a flawed mapping system.
They saw that one could divide the oblate spheroid into segments, like the Oranges that they were enjoying when boiled with sugar and made into Marmalade.
Good result. It worked. But.
They didn't spot that Lines of Latitude might have been better replaced by choosing an East and West Pole and cutting the sphere into segments akin to those that Lines of Longitude do.
They would then have been able to work out the best way to eat a Grapefruit.
Notwithstanding this error, some bright spark realised that multiples of 12 offer more outcomes of subdivision than those of 10. Good point, and well made.
Then at some point (and I'd welcome some input from the Creationistas for an exact date) we noticed the stars and Sun/Moon/Planets, and made some notes. And with some sums worked a few things out so that we could guess our location.
A bit further along, Radio was created, (again, input welcomed) and some people (who turned not to be on our 'like' list) came up with "Ultrakurzwellen-Landefunkfeuer".
This was not good news.
But it was a turning point (sorry). Thereafter the electronic and radio based systems (with the exception of the simple RDF) relied on lines on maps for co-ordination which were entirely arbitrary. The 1980s gave us (civilians) electronics which would do their stuff and give us Lat/Long - but only thinking in 1/0s internally.
Today the gps system does not have a clue about units that we would use. They work out where we are and, in much the same way as we would say 'print' on some data, it stuffs it through the last bit of software to demonstrate some sort of recognisable position.
That, folks, is my take on the history of mapping.
Now if I could start.......
Nemo Me Impune Lacessit
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Just a personal opinion but, as already pointed out by several above, the current system is the best way to go. Using separate units of measurement for speed, height, RVR/viz etc. avoids misunderstanding and the speed with which the current, commercially orientated, flying schools are churning out new pilots these days I'm all in favour of as many built in safety devices as possible. Happy to see there is no serious effort by any major aviation organisation to change the present, western system.