FERRET

Some codes from ferret user-mailing list.

The transformations @CIA, and @CIB (see docs pasted below) allow you to know how far you are from a valid point. You can use these to create a mask showing how large the gaps are:

    let gap_size = my_var[i=@cia] + my_var[i=@cib]

    let gap_mask = if gap_size LE BIGGEST_GAP_ALLOWED THEN 1

Now you  use

    let my_answer = my_var[i=@fln] * gap_mask

Or you can combine the whole mess into one expression (bigger than 15 point gap to be

rejected):

    let my_answer = IF (my_var[i=@cia]+my_var[i=@cib]) LE 15 THEN my_var[i=@fln]

Alternatively, you can use the CDA & CDB transformations and work in terms of gaps

measured in time or distance instead of number of missing points.

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     2.4.29 @CDA--closest distance above

     The transformation @CDA will compute at each grid point how far it is to the  closest valid point above this coordinate position on the

     indicated axis. The distance will be reported in the units of the axis. If a      given grid point is valid (not missing) then the result of @CDA for

     that point will be 0.0.   

   2.4.30 @CDB--closest distance below

     The transformation @CDB will compute at each grid point how far it is to the   closest valid point below this coordinate position on the

     indicated axis. The distance will be reported in the units of the axis. If a  given grid point is valid (not missing) then the result of @CDB for

     that point will be 0.0.

     2.4.31 @CIA--closest index below

    The transformation @CIA will compute at each grid point how far it is to the closest valid point above this coordinate position on the   indicated axis. The distance will be reported in terms of the number of pointsThe transformations @CIA, and @CIB (see docs pasted below) allow you to know how far you are from a valid point. You can use these to create a mask showing how large the gaps are: