Measuring the location of an object in 3D space using the vector in respect to some coordinate system ( {\bf e}_x, \, {\bf e}_y, \, {\bf e}_z):
| (1) | {\bf r} = (x, \, y, \, z) = x \cdot {\bf e}_x + y \cdot {\bf e}_y + z \cdot {\bf e}_z |
See also
Natural Science / Physics / Measuring