Latitude

Latitude is used to express how far north or south you are, relative to the equator. If you are on the equator your latitude is zero. If you are near the north pole your latitude is nearly 90 degrees north. If you are near the south pole your latitude is almost 90 degrees south.

Conventionally latitude is expressed as degrees north or south. For inputting to the satellite pointing calculator south latitude figures need to be input as negative numbers.

Note that from small regions around the north or south poles you cannot see geostationary satellites at all. The geostationary satellites are below the horizon and directly above the equator, in a circle all around.

Longitude

Longitude shows your location in an east-west direction, relative to the Greenwich meridian. Places to the east of Greenwich (such as Middle East, India and Japan) have longitude angles up to 180 degrees east. Places to the west of Greenwich (such as North and South America) have angles up to 180 deg west. For inputting to the satellite pointing calculator longitude west figures need to be input as negative numbers.

  Geostationary satellites are located in orbit directly above the equator and stay in the same place in the sky since they go around the earth at the same angular speed as that of the earth as it rotates. Satellite locations may thus be defined by longitude only. The use of east and west longitudes is popular for public use since the numbers are smaller. Use of degrees east only (0 to +360 deg, going east from Greenwich) however is my preference since the satellites go around this way and it makes sense for the numbers to keep increasing as the satellite moves forwards. Trying to do orbit calculations is bad enough without having numbers that keep switching forwards and backwards. Many satellite operators also use the 0 to +360 deg method, but may additionally provide the "deg west" notation for some output publications.