On maps, why is North always up.

[gnoitall]

@Lemur866

[QUOTE=John W. Kennedy;12840919
Putting the equator nearer the bottom is not necessary, but, because the Mercator projection can’t go all the way to the poles (they’re infinitely far away), which means that you have to pick a northern and a southern latitude to cut it off, and because Spitzbergen is further north than the Cape of Good Hope is south and most people aren’t really interested in the details of Antarctica, you can cut off more of the Southern Hemisphere with no important loss.[/QUOTE]

No, the Mercator projection CAN go all the way to the poles, it’s just that the poles are represented by a line rather than a point.

Actually, come to think of it, Lemur866 is right. You really can’t cross the poles on a normal Mercator projection. I was confused earlier.

That means that you can continue on a constant heading forever. Your apparent projected ground track will simply become shorter and shorter as you approach the pole.

[John_W.Kennedy]

As I said, you can’t get to the poles on a Mercator, because they’re infinitely far away. (The lines of longitude are represented as parallel lines, and parallel lines never meet.)

But you do keep the same compass heading as long as you follow a straight line (assuming true, rather than magnetic headings). It’s the defining characteristic of the projection, and its raison d’être.

[JoelUpchurch]

@Floater

@Ignatz

He preferred to draw his site plat maps with the viewer looking (up) into the entrance to the development site.

In orienteering you always hold your map so that whatever direction is in front of you is up.

All the GPS system I’ve tried use this convention. I had one that a North is up option that I tried, but I quickly went back to front is up.

If you use Google Earth, then up is whatever direction you want.

[Gedd]

@Civil_Guy

GHO57:

…So your country’s going to deny having anything to do with supplying Santa Claus (also known as Saint Nicholas, Sinterklaas, Father Christmas - fellow’s got a lot of aliases, suspicious all by itself) with magical reindeer, huh?

“He sees you when you’re sleeping, he knows when you’re awake. He know’s if you’ve been bad or good . . .” To quote a Calvin and Hobbes cartoon, “Santa Claus: Kindly old elf, or CIA spook?” :dubious:

[Powers]

@John_W.Kennedy

As I said, you can’t get to the poles on a Mercator, because they’re infinitely far away. (The lines of longitude are represented as parallel lines, and parallel lines never meet.)

While what you say is true about the Mercator, there are other parallel-meridian projections that do not have the poles at infinite distance.

Equirectangular projection

Powers &8^]

[John_W.Kennedy]

@JoelUpchurch

@Floater

In orienteering you always hold your map so that whatever direction is in front of you is up.

All the GPS system I’ve tried use this convention. I had one that a North is up option that I tried, but I quickly went back to front is up.

If you use Google Earth, then up is whatever direction you want.

Back in the old days (the 90s), when having a GPS meant having a GPS sensor attached to your laptop (actually, you can still get such a configuration, if you want it), you might have a north-up overview combined with a forward-up detail. Modern hand-size devices can’t afford the screen real-estate.