Minecraft wiki entry for Measuring_distance, associated text: 1 Metric units
2 Imperial/U.S. customary units
3 Viewing exact coordinates in-game
4 Relative to green line
5 Calculating coordinates of distant locations
6 Conserving markers
7 Volume and surface area
8 Using the Euclidean distance formula
8.1 Example
8.2 Euclidean distance in 3 dimensions (including elevation)