The concept of “up” comes from our real but narrow experience with gravity on what seems to be, locally, typically a fairly flat earth. Up is that place it requires energy to go. Based on that definition, summit of Mount Everest, the highest place on Earth at 29,029 ft might be up on all maps, but it isn’t.
… Up on a map is a human construction, not a natural one. Some of the very earliest Egyptian maps show the south as up, presumably equating the Nile’s northward flow with the force of gravity. And there was a long stretch in the medieval era when most European maps were drawn with the east on the top. If there was any doubt about this move’s religious significance, they illuminated it with their maps’ pious illustrations, whether of Adam and Eve or Christ enthroned. This east as up approach apparently explains not only where the word “orientation” comes from, but also quite possibly how we get “north” from an old Germanic word meaning left. In the same period, Arab mapmakers often drew maps with south facing up. One theory is they did this because they thought right was preferable to left, but east was the most important direction, so they privileged south, the direction to your right if you’re facing east. Which makes a certain convoluted sense until you realize that this would make east left, undermining the initial left is bad logic. Another theory is they wanted to be on top of the Christians. (Which in itself takes for granted that they were more obsessed with besting European Christiandom than any of the other, potentially more advanced civilizations on the other sides of them.) Hence another popular theory, that the Muslims adopted south is up from the Chinese, along with the compass itself. Things changed with the age of exploration. Like the Renaissance, this era didn’t start in Northern Europe. It began in the Mediterranean, somewhere between Europe and the Arab world. In the fourteenth and fifteenth centuries, increasingly precise navigational maps of the Mediterranean Sea and its many ports, called Portolan charts, appeared. They were designed for use by mariners navigating the sea’s trade routes with the help of a recently adopted technology, the compass. These maps had no real up or down—pictures and words faced in all sorts of directions, generally pointing inward from the edge of the map—but they all included a compass rose with north clearly distinguished from the other directions.
According to StraightDope:
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 opines. … north prevailed over the long haul. By the time Southern Hemispheroids had become numerically significant enough to bitch, the north-side-up convention was too well established to change.
It might make even more sense someday to orient maps of the earth based on orientation of the Milky Way galaxy, that is, assuming we can fully accept it as our new home. The Milky Way is tilted about 60 degrees relative to the rotational axis of Earth. This is so because we are currently in but not of the Milky Way Galaxy.
The Sun, the Moon, our planet and its siblings, were not born into the familiar band of stars known as the Milky Way galaxy, but we actually belong to a strange formation with the unfamiliar name of the Sagittarius Dwarf galaxy! … The fact that the Milky Way is seen in the sky at an angle has always puzzled astronomers. If we originated from the Milky Way, we ought to be oriented to the galaxy’s ecliptic, with the planets aligned around our Sun in much the same angle as our Sun aligns with the Milky Way. Instead, as first suggested by researcher Matthew Perkins Erwin, the odd angle suggests that our Sun is influenced by some other system. Together with data from the Two-Micron All Sky Survey we now know what it is. We actually belong to the Sagittarius Dwarf galaxy.
We are unsettled, strangers in a strange land. We are lost in space, devoured by a white whale. We sail, carried by the current of gravity, sideways through a foreign galaxy. This is not our home, yet we have made it so. So, get on up.