What method involves measuring evidence in relation to two or more fixed points outside the scene?

The triangulation method of measurement is used in forensic science to accurately record the location of evidence at a crime scene. This technique involves establishing two or more fixed points, which can be easily identified and located within the environment. By measuring the distance from these fixed points to the evidence, investigators can create a precise map or diagram of the scene, ensuring that evidence is documented with a high degree of accuracy. This is particularly useful in complex scenes where multiple pieces of evidence are scattered and precise locations need to be maintained for later analysis.

In contrast, the linear measurement method typically involves measuring distances in a straight line, often between two fixed points without the triangulation aspect. The grid method involves creating a grid over the scene for systematic searching but does not specifically rely on fixed points outside the scene. The coordinate system method uses a grid system or Cartesian coordinate plane but may not rely on fixed reference points in the same manner as triangulation. Each of these methods serves its purpose in crime scene documentation; however, the triangulation method is specifically designed for measuring evidence with reference to fixed external points, making it the most accurate choice in this context.