What method involves taking two measurements from a reference point?

The coordinate method is the correct answer because it utilizes two measurements from a reference point to establish a specific location within a defined grid or coordinate system. This method is often used in various fields, including surveying and mapping, where precise positioning is essential. By taking two measurements—typically one for the horizontal and one for the vertical position—an accurate coordinate can be determined.

In contrast, triangulation involves measuring angles from known points rather than direct distances from a reference point, while the proportional method typically relies on ratios and scaling rather than direct measurement. Measurement estimation does not focus on accurate measurements and often incorporates estimations rather than systematic measurement techniques. Therefore, the coordinate method stands out as it directly involves taking two measurements to establish a precise location.