The image used for rendering the boundary layer on the associated CelestialObject within a ViewWindow. BoundaryLayers use specialized image files called B-spline-interpolated Signed Distance Fields. These grayscale images are encoded with information that allows FreeFlyer to render the coastlines and up to 10 coastline offset borders very quickly. The level of detail that you will see in the coastlines depends on the resolution of the boundary layer image file you select. The grayscale value of each point in the image represents the Vincenty distance (across the surface of the WGS 84 ellipsoid) in kilometers from the location of the center of that pixel to the nearest land/water boundary. All the coastline boundary layer files delivered with FreeFlyer use the 0.9 grayscale value as the coastline boundary value, and the maximum coastline offset border distance that can be rendered is 500 km.
Timing Precision Mode
This page describes functionality in nanosecond timing precision mode.