Mainly the 180 degree line.
The international date line is measured approximately from the 180 degree median longitude line. This is an arbitrary line that determines when a date change takes place within the day.
180 degrees east/west longitude
The International Date Line corresponds closely, but not exactly, to the 180 degree line of longitude.
180 degrees
Mainly the 180 degree line.
This imaginary line of longitude is the 180 degree line of Longitude. It is on the opposite side of the planet to the Greenwich meridian. Thus when it is 12 o'clock mid day at Greenwich, it is midnight on the 180 degree line of longitude. As you will know midnight denotes the start of a new day (and therefore a new day's date) and this is why it is called the International date line. In reality the internationally agreed path of the International date line does not follow the 180 degree longitude line. This is because if it did some pacific island countries would find themselves in two days at once (most confusing!). The line therefore jiggles about a bit as is crosses the pacific. See related link below.
One degree east and one degree west. You're probably looking for the prime meridian and the International Date Line, but the IDL isn't a specific line of longitude.
The 180 degree longitude is often miscalled international date line, when it is actually called the Anti Meridian.The date line is not a meridian or line of longitude because it is not a straight line as it deviates to separate geographical places, certain island groups for instance.See the link below for an image.The longitude that runs through Greenwich England is the prime meridian, which is 0 deg longitude.
The first pair is.
Whether travelling to the West or to the East from the Prime Meridian (zero Longitude) the International Date Line is 180 degrees Longitude.
No, the international date line is a line of longitude, not latitude.
It varies, because the International Dateline doesn't follow a single meridian.There are several zigs and zags in it. But in the spirit of your question, theDateline is nominally directly opposite the Prime Meridian, at 180° longitude.