### GDF v1

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.