Question

which type of mapping requires taking at least four measurements for each piece of evidence?
triangulation
polar/grid
rectangular coordinate
baseline

Explanation:

Triangulation typically requires multiple measurements from different points to accurately map evidence. In triangulation, at least four measurements (usually distances or angles from multiple fixed - reference points) are often taken for each piece of evidence to precisely locate it. Polar/grid, rectangular coordinate, and baseline mapping do not necessarily require a minimum of four measurements per piece of evidence.

Answer:

Triangulation