cdfpsel −− select specific parcels from cdflagr output
cdfpsel condition_1 condition_2 ...
Cdfpsel works in conjunction with the Lagrangian trajectory calculator cdflagr to provide more control over which parcel trajectories are retained. In particular, cdfpsel passes only those parcels that satisfy all of the conditions specified on the command line somewhere along the parcels’ trajectory. A file generated by cdflagr is expected on the standard input and the results appear on the standard output.
Conditions are of the form ’variable operator constant’, where variable is the name of a variable field defined in the input file. Operator is one of four conditions: > means greater than, < means less than, /> means not greater than, and /< means not less than. Thus, ’x > 5’ means that only those parcel trajectories will be passed for which the variable field x takes on a value greater than 5 somewhere along the trajectory. Note that ’x /< 5’ only passes those trajectories where x is never less than 5, which is distinct in meaning from the previous condition.
Cdfpsel deletes trajectories by simply making data values bad for these trajectories. Thus, the actual sizes of files do not decrease.
Command line arguments always need to be quoted with this program.