You determine your position by matching the line figures displayed on the set to a set of Loran _______________________.

The correct answer is "charts." When determining your position using Loran, the process involves comparing the line figures displayed on the Lorank set to a specific set of charts that contain the geographic information needed for navigation. These charts show various features of the area, including coastlines, depths, hazards, and navigational aids.

Charts are essential for interpreting the lines generated by Loran, as they provide a reference framework that helps in pinpointing the exact location on the water and ensuring safe navigation. The other options, such as signals or coordinates, do play a role in navigation but do not specifically represent the process of matching with figures displayed; instead, they refer more to the input or the general measures used in navigating rather than the comparison necessary for establishing exact position using Loran data.