What's on your longitude?

[kphoger]

You are the one treating east as a straight line as if the world was flat and thus a direction with a definition of 'perpendicular to north-south lines' can be straight, rather than curved.

Bear with the devil's advocate, here.  Turning the tables, one could just as easily wonder why you think north-south lines can be straight rather than curved.  See the flipped globe illustration above.  Do you have an answer to that that doesn't involve earth's rotation (which factors not one bit into how people think of directions).  What I mean is, looking east out your window is functionally no different than looking north out your window, yet the lines described by "east" and "north" are not the same, i.e. straight or curved.

You don't call Red Eric 'Red', do you.

that said, given that your username is all lowercase, it is not completely intuitive to parse "si" to be a shortening of a name.  (Simon, Silas, Siberian Husky, etc.)  if your name were "prelude si" I would not hesitate to call you "prelude".

This whole time, I just figured it was an initialism, written in textspeak.  I always say it to myself as English, es i, which my brain comprehends as English, metric system. 

[Takumi]

if your name were "prelude si" I would not hesitate to call you "prelude".

...but that's MY nickname!

[Alps]

Basically, we just need an East Pole and a West Pole, and then we'd all be happy (as long as we switch to metric).

I grew up imagining East and West Poles at (0,0) and (0,180), both over open water. However, I could never figure out what that meant. Once I learned more about the North and South Poles actually having significance, I dropped that notion.

[vtk]

Your version of 'traveling east' is a straight line that is only east at one point, but north, south and west at three others.It is also not reciprocal with 'traveling west'.

No, my definition of travelling east is the same as yours. It's my definition of what's due east of me that's on a great circle.  Following that great circle (starting in an easterly direction) does involve changing direction a bit as measured in the traveller's local coordinate system, but not as much as you characterized in the above quote.  The locally-measured deviation from local due east is never more than the latitude angle of the starting point, and certainly never west. *

As far as reciprocals, are we talking about the relative directional relationship between two points, or are we talking about travel?  If I travel due east 1000 miles, then travel due west 1000 miles, I return to my starting point.  But if I identify a point 1000 miles due east of me, and then go there, my starting point is 1000 miles away but not exactly due west. NE2 and I have already mentioned this phenomenon.

When you insist that they are the same, it sounds to me as if you are the one imposing 2D geometry on a 3D sphere.

1)where was I insisting they were the same?

I have made statements about what is east of me, and you say I'm wrong because something about traveling east. That's when you seem to insist that the two concepts (which you didn't quote) are the same.

I'm beginning to think that the problem is not 2D versus 3D thinking, but a choice of coordinate system.  You seem to prefer a global spherical coordinate system of ρ,θ,φ – possibly converting to/from geocentric cartesian x,y,z when necessary for intermediate calculations.  I prefer a global geocentric cartesian x,y,z, converting to/from spherical ρ,θ,φ for as necessary for communication, but I also think in terms of local cartesian x,y,z coordinate systems with the origin at a point on the Earth's surface and x and y aligned to east and north at that point.  We've both been largely neglecting elevation in our discussion, so while you don't specify ρ, I don't specify local z. Both of those omissions make the earth Flat in different ways if the missing variable isn't reconstructed.

You are the one treating east as a straight line as if the world was flat and thus a direction with a definition of 'perpendicular to north-south lines' can be straight, rather than curved.

East is a direction, not a path.  East is therefore not straight or curved.  You can define a path whose direction is east at every point along its length, and you get a parallel of latitude. Or you can define a path which begins in the direction of east, but has no curvature; that's a line into space. Or you can define a path that begins in the direction of east, and has the minimum curvature required to follow the Earth's surface (there's a general term which eludes me for such a minimum-curvature path constrained to a surface) and then you get a great circle.

Your use of great circles may have merit, but to call it 'east' is just totally wrong.

It all amounts to a differing opinion on the definition of "is east of".

Yes, and you are using a totally different one to everyone else.

I'm certainly not saying that great circles define "east" as such a general term – that would indeed be wrong, unless someone defines an "east pole", which I'm not advocating.  The collection of points that "are due east of" a given point on the Earth's surface lie on a great circle, as I define the phrase "is/are due east of".  My definition is no broader than that.  I'm certain I'm not the only person who supports that definition, though I won't assert it's a large number. 

And yes, I called you "english" as if it's your name. Not because you are from England, but because your "name" on the forum appears as "english si".  I simply shortened it, like how Bill Clinton calls his wife Hillary and not Hillary Clinton.

Yes, his first name. You don't call Red Eric 'Red', do you.

Do you expect me to know your real name?

I've given you a shorted version of my first name. What else do you need to not call me an adjective?

Who is Red Eric?  I don't claim to be good at world history.  And I wouldn't be surprised if folks called him Red, particularly on the Internet. Long ago I was a regular at a chatroom for nudists. Another frequent visitor used the handle "gay_nude_oz_guy".  (Not meant to be overtly sexual, as it might be interpreted in a more general chatroom.)  Many people just called him "gay" for short, even though "guy" was the noun.

Anyway, "english" isn't always an adjective; it can be a noun too.  Understanding it as an adjective requires a noun to be modified, in this case "si" which is apparently a proper noun, your name – this was not clear to me before.  I'm not familiar with many names which would shorten to Si, and I've never met anyone who does so, and besides, you didn't capitalize it.  For that matter, had you capitalized it, I might have interpreted it as the symbol for Silicon.  As it is, I thought the "si" in your name was spanish for "yes", and "english" was a noun (the language).  Like if someone asked a Cuban merchant if he spoke English, and the merchant responded "English, sí", comedically demonstrating either an inability or unwillingness to consistently use the potential customer's preferred language. Frankly, I'm a little disappointed to learn that your forum handle isn't a joke about mismatched languages. 

That said, you seem to think that traveling due east means travelling west at some point

That is, at best, an exaggeration of an unwarranted generalization of what I said.*  Have I clarified things in this post, or do I need to explain in more formal mathematical terms?  Or should I just say you have misunderstood me and give up?



*Oh, wait, I think I figured out where you got that "travelling east includes travelling west" paradox.  I guess I did sort of say that indirectly, but it's not as absurd as you color it.  I really need to sleep right now, but I'll try to address that soon. 

[NE2]

As far as reciprocals, are we talking about the relative directional relationship between two points, or are we talking about travel?  If I travel due east 1000 miles, then travel due west 1000 miles, I return to my starting point.  But if I identify a point 1000 miles due east of me, and then go there, my starting point is 1000 miles away but not exactly due west. NE2 and I have already mentioned this phenomenon.

Buh? If you identify a point 1000 miles due east of you, and going due east 1000 miles does not get you to that point, something is very wrong with your terminology.

[vtk]

Buh? If you identify a point 1000 miles due east of you, and going due east 1000 miles does not get you to that point, something is very wrong with your terminology.

A point 1000 miles due east of me can be reached by travelling 1000 miles along a great circle path which is due east at my starting point. If I instead travel due east for 1000 miles – correcting my course along the way to keep a due-east heading – I reach a different point which is just shy of 1000 miles away from my starting point, and the direct direction (not the direction of the path I travelled) from start point to end point is a little off of east, as measured from either the start point or the end point. 

...All of this assumes I am nowhere near the equator at any time in this scenario.



I think I'll make some graphics, animated if necessary, to illustrate the points I've made.

[NE2]

I understand what you mean, but your terminology really really sucks.

[kphoger]

Buh? If you identify a point 1000 miles due east of you, and going due east 1000 miles does not get you to that point, something is very wrong with your terminology.

A point 1000 miles due east of me can be reached by travelling 1000 miles along a great circle path which is due east at my starting point. If I instead travel due east for 1000 miles – correcting my course along the way to keep a due-east heading – I reach a different point which is just shy of 1000 miles away from my starting point, and the direct direction (not the direction of the path I travelled) from start point to end point is a little off of east, as measured from either the start point or the end point. 

Buh? If you identify a point 1000 miles due east of you, and going due east 1000 miles does not get you to that point, something is very wrong with your terminology.

A point 1000 miles due east of me can be reached by travelling 1000 miles along a great circle path which is due east at my starting point. If I instead travel due east for 1000 miles – correcting my course along the way to keep a due-east heading – I reach a different point which is just shy of 1000 miles away from my starting point, and the direct direction (not the direction of the path I travelled) from start point to end point is a little off of east, as measured from either the start point or the end point. 

Buh? If you identify a point 1000 miles due east of you, and going due east 1000 miles does not get you to that point, something is very wrong with your terminology.

I think we've reached an impasse.

[vtk]

My terminology doesn't fit your expectations which are based on 2D Euclidean geometry, so it sucks?  I suppose you are entitled to your opinion.  I, however, believe terminology that depends too much on the cardinal directions being special is problematic.  It causes people to get used to thinking about geography only from specific, possibly distorted perspectives.  I like to be able to turn the globe around in my head and look at it any which way I want.

Latitude, longitude, loxodromes and the Mercator projection all have their uses, but they're not the only valid way of understanding geospatial relationships.  The methods I've outlined work too, and to assert that they are inferior – not for any specific uses, but inferior in general – suggests a lack of objective thinking.  I'm not the only one who thinks about geospatial relationships this way, either.  The azimuthal equidistant projection has been around for a very long time. 

There is not an applicable emoticon I can use here.

[NE2]

Your terminology is self-contradictory.

[vtk]

Your terminology is self-contradictory.

My terminology is nuanced.

[hotdogPi]

Going south, I pass Cambridge, Boston, and Fall River. After a long stretch of ocean, I go into the Dominican Republic. I go into South America, and I miss Santiago by a few miles.

Going north, I pass the White Mountains, and I miss Quebec City by a few miles.