On Wed, 6 Apr 2022 at 08:35, Greg Ewing <greg.ew...@canterbury.ac.nz> wrote: > > On 6/04/22 3:47 am, Christopher Barker wrote: > > And they are -- degrees latitude and degrees longitude are very > > different units :-) > > I'm thinking more of a local Cartesian coordinate system rather > than lat-long. > > Think about this: You're driving north in a car that's 3m long. > You turn east. Do you now have to measure the length of your > car in different units? > > And what about the circumference of a circle? It's going in > uncountably many directions at different points. Do we need > a similarly uncountable number of units to measure it? > > Or do we just say "all distances are in metres" and be done > with it? >
I would say that degrees latitude and degrees longitude are both the same type of unit: a unit if *angle*. They do not correspond to the same number of meters, but they're not units of distance. There are multiple ways in which you can measure distance by angle, ranging all the way up to the "second of parallax", which is effectively calculating the height of an isosceles triangle based on the interior angle and a base of 1AU. I don't think anyone would ever say that a parsec (several light years) should be considered equivalent to a second of latitude (a handful of meters) just because they both have an angular size of one second! Length is measured in a variety of units, but the degree ain't one of 'em. ChrisA _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/INHQY5JNQJZ7WBYTOM7GASRZRUK3JV4J/ Code of Conduct: http://python.org/psf/codeofconduct/
