Displays a list of the permanent reference points currently known to the system. The locations are displayed in pixel coordinates, giving the reference locations, the reference size (in pixels) and the current locations. The presence of a star (*) beside one of the current location entries indicates that the point concerned is an outlier in the sense that it has the largest residual in the mapping process. The mapping coefficients and the rms error (residual) are also displayed. Many of the routines in DigImage utilise this rms error to give an indication of how good the mapping is. A poor mapping (one with a large rms residual) generally indicates a low quality image; DigImage may try to acquire the image again. With six permanent reference points, an acceptable rms error is less than 0.25 (pixels), with less than 0.1 frequently achieved. Note that the rms errors are available to command files through !!R0 (current to reference) and !!R1 (reference to current). Typically you will need to use the floating point specifier in conjunction with these variables (e.g. !!GR0).