The original GDF format contains visibilities consisting of:
- 7 data associated parameters, in a fixed order: u, v,
w, date, time, first antenna, second antenna
- an array of complex visibility elements, that contain each a
real part, an imaginary part and a weight
Note that in this original format, u,v and w are in
meters, the date is a CLASS date, time is in
seconds. The w column was often replaced by the scan number
scan for flagging and editing purpose.
