It's worth noting that the kilometre (and by extension the whole metric system) is also based on the circumference of the Earth.
Instead of dividing the pole to the equator into 90 degrees, divide it into 100 gradians (or 100%, as cyclist might describe it). Then if you divide each gradian by 100, into centigrades, each centigrade is equal to 1km distance on the surface of the Earth. (In the same way that 1 second of arc is equal to 1 nautical mile).
All other measures in the metric system were extrapolated from this fundamental measurement, even though they were late standardised by more accurately definable measurements.
Even though accuracy of the measurement of the circumference of the Earth has improved since the metric system was developed, it's still quite reasonable to estimate the circumference of the world at 40,000 km.
The grid reference system is bespoke/unique to Ireland (and other countries have their own unique systems). It is designed to keep distortion of shape to a minimum and to have a km lattice along both axes.
Grid reference is similar to the Universal Transverse Mercator system favoured by surveyors and the construction industry, but as the name suggests, UTM is more universal, and not bespoke to a particular country.
You can meditate over that as you are chewing up the kms down the east coast.
You are doing great Charlie. Won't be long before you are back in WC.
Interesting post Charlie.
It's worth noting that the kilometre (and by extension the whole metric system) is also based on the circumference of the Earth.
Instead of dividing the pole to the equator into 90 degrees, divide it into 100 gradians (or 100%, as cyclist might describe it). Then if you divide each gradian by 100, into centigrades, each centigrade is equal to 1km distance on the surface of the Earth. (In the same way that 1 second of arc is equal to 1 nautical mile).
All other measures in the metric system were extrapolated from this fundamental measurement, even though they were late standardised by more accurately definable measurements.
Even though accuracy of the measurement of the circumference of the Earth has improved since the metric system was developed, it's still quite reasonable to estimate the circumference of the world at 40,000 km.
I had no idea, that’s fascinating. I’m assuming that then is the basis for the grid reference system?
Not exactly.
The grid reference system is bespoke/unique to Ireland (and other countries have their own unique systems). It is designed to keep distortion of shape to a minimum and to have a km lattice along both axes.
Grid reference is similar to the Universal Transverse Mercator system favoured by surveyors and the construction industry, but as the name suggests, UTM is more universal, and not bespoke to a particular country.
You can meditate over that as you are chewing up the kms down the east coast.
You are doing great Charlie. Won't be long before you are back in WC.