While the Earth's equator divides north and south geographically, the ecliptic, which is the Sun's path, is what divides the sun's torroidal zodiac field into north and south. Both are off by about 23.5 degrees, and where they intersect is zero Aries(and zero Libra). All bodies except the Sun are either north or south of the ecliptic and this called latitude.

A planet's north and south latitude can be helpful in astrolocality, narrowing down the region each planet will manifest in most strongly. I've often wondered why there weren't tweve divisions from north to south just as there are from west to east (the twelve zodiac signs) so that the Earth would be divided into 144 regions(12x12), but north and south is better than nothing.

Below is Trump's astrolocality map showing his planets and factors. You will note that the vast majority of his planets are north latitude and over North America, where they should be. Only the Moon and Ceres and Chiron are south of the ecliptic and to the East. The Sun, North Node, Ascendant, and Midheaven are always at zero latitude and affect both north and south equally. In fact, the closer a body is to the ecliptic, the more it will affect both sectors equally.