The meridian on the opposite side of the earth from the prime meridian is called the anti-meridian. [3] X Research source

Latitude and longitude are measured in degrees rather than absolute units of measurement (such as miles or kilometers) because the Earth is spherical. While the distance between degrees of latitude is constant (60 nautical miles or 111. 12 km), the Earth’s shape causes the distance between degrees of longitude to decrease as you approach the poles. [5] X Research source

For example, the North Pole is at 90°N, meaning it is 90° north of the equator. The antimeridian is at 180° either east or west from the prime meridian. The Great Sphinx of Giza in Egypt is located at 29°58′31″N, 31°8′15″E. This means it is just under 30° north of the equator in latitude, and about 31° east of the prime meridian in longitude.

Latitude graticules are marked along the east and west edges of the map. Longitude graticules are marked on the north and south edges. Depending on the scale of your map, the graticules may mark fractions of degrees rather than whole degrees. For instance, there may be a Graticule marked at every minute within a degree instead of every degree (e. g. , 32°0′, 32°1′, and so on). The map should also indicate where the latitude and longitude depicted are relative to the equator and prime meridian, respectively (e. g. , North or South, East or West). Take care not to confuse the latitude and longitude lines with UTM lines, another type of grid coordinate system often found on maps. UTM numbers are usually marked in a smaller text (and without degree symbols) along the edges of the map, and UTM gridlines may be marked in a different colour from latitude and longitude lines.

If your map shows seconds, find the second closest to where each line intersects the latitude or longitude scale at the edge of the map. For example, if your latitude line falls about 5″ above the 32°20′N line, your point is at a latitude of approximately 32°20′5″N. If your map shows minutes, but not seconds, then you can estimate your latitude or longitude to within 6 seconds by dividing the space between each graticule into 10ths. If your longitude line falls about 2/10 to the left of the 120°14′E line, then the longitude is roughly 120°14′12″E.