It's either Latitude & Longitude or the Prime Meridian
The imaginary line that extends straight out from the center of a reflective surface is the optical axis.
That would be the "ecliptic plane".
To locate the epicenter you use the speed of waves that travel from the epicenter to the seismic sensor locations. With two sensors you are able to narrow the location to two places (when on a surface using intersecting hyperbolas). With a third sensor you have the location on a surface and below ground. This third sensor is why they call it tri - angulation but the angles are hard to find without HS trigonometry and other mathematics.
Epicenter
To determine latitude and longitude the minimum number of satellites that the receiver must lock onto is three. To also determine elevation the minimum number of satellites that the receiver must lock onto is four. If the receiver can lock onto more satellites then it can improve the calculations to get a more precise location.
In terms of geography, an absolute location is a point on the earth's surface expressed by a coordinate system such as latitude and longitude.
Relative Location: A location of a place in relation to another place. Absolute Location: A point on the earth's surface expressed by a coordinate system such as latitude and longitude.
So that we may all agree on and communicate absolute locations on the surface of the globe.
So that we may all agree on and communicate absolute locations on the surface of the globe.
Relative to what? Other cities? The surface of planet earth?
Absolute Location.
Longitude
infrared
Geographic coordinates, such as latitude and longitude, precisely identify a location on Earth's surface.
How far north or south of the equator the location lies.
anywhere
Lines of longitude and latitude provide a coordinate system that allows you to pinpoint a specific location on Earth. Longitude lines run north-south and measure east or west of the Prime Meridian, while latitude lines run east-west and measure north or south of the Equator. By using the intersection of these lines, you can determine the absolute location of a place on the Earth's surface.