why all maps are designed with North at the top?

Answer 1

Most of the conventional maps have north at the top. However, there are other maps which do not have the same orientation.
Historically, maps and the mariner's compass were closely associated and the magnetic property gave a sense of direction to the men venturing in to the un-known seas.
So, maps were drawn with reference to the magnetic direction.
When people explored in to the southern hemisphere, reference point continued to be north (where the compass continued to point) and hence the usage.
Though I have never crossed the equator, I was told that "reverse maps" are not that rare in Australia.

The links below are quite helpful
http://flourish.org/upsidedownmap/
http://en.wikipedia.org/wiki/Dymaxion_map
http://en.wikipedia.org/wiki/Reversed_map

Answer 2

The notion that north should always be up and east at the right was established by the Egyptian astronomer Ptolemy (90-168 AD). "Perhaps this was because the better-known places in his world were in the northern hemisphere, and on a flat map these were most convenient for study if they were in the upper right-hand corner," historian Daniel Boorstin said. Mapmakers haven't always followed Ptolemy; during the Middle Ages,, maps often had east on top--whence the expression "to orient."

Answer 3

People have been using the "North Star" for direction since the earliest days of recorded history. Since the "North Star" is up, it follows that maps would have North on top.
Most of our recorded history comes from the Northern Hemisphere.

Answer 4

because of convention. You can produce maps that have the south pole on top and it would be the same earth, except everyone would have trouble recognising your representation of the world

Answer 5

THis is not true. I've seen a map of the world that was upside down in bar I was in.

Answer 6

...huh???
Because the North Pole is in the Arctic, which is north???

x_x

Answer 7

It is good direction for common purpose ie.straigth ahead.