If the projection from CHIPCOORD to sky coordinates is performed by a duration-weighted sum of transforms corresponding to the spacecraft attitude in a sequence of time bins, it may be desired to adjust the weights to correspond not to the durations of the attitude bins but to the total good time per bin. Hence a facility has been provided to provide a table of good time intervals (GTIs), via the parameters withgtitab and gtitab. If such a table is supplied, the task adjusts the transform weights accordingly. (Note that if withatttab=`no', GTIs have no effect.)