Next: Normalization and Integration, Previous: ncwa netCDF Weighted Averager, Up: ncwa netCDF Weighted Averager
The mask condition has the syntax mask_var mask_comp mask_val. The preferred method to specify the mask condition is in one string with the ‘-B’ or ‘--mask_condition’ switches. The older method is to use the three switches ‘-m’, ‘-T’, and ‘-M’ to specify the mask_var, mask_comp, and mask_val, respectively. 1. The mask_condition string is automatically parsed into its three constituents mask_var, mask_comp, and mask_val.
Here mask_var is the name of the masking variable (specified with ‘-m’, ‘--mask-variable’, ‘--mask_variable’, ‘--msk_nm’, or ‘--msk_var’). The truth mask_comp argument (specified with ‘-T’, ‘--mask_comparator’, ‘--msk_cmp_typ’, or ‘--op_rlt’ may be any one of the six arithmetic comparators: eq, ne, gt, lt, ge, le.
These are the Fortran-style character abbreviations for the logical comparisons ==, !=, >, <, >=, <=.
The mask comparator defaults to eq (equality). The mask_val argument to ‘-M’ (or ‘--mask-value’, or ‘--msk_val’) is the right hand side of the mask condition. Thus for the i'th element of the hyperslab to be averaged, the mask condition is
mask(i) mask_comp mask_val.
[1] The three switches ‘-m’, ‘-T’, and ‘-M’ are maintained for backward compatibility and may be deprecated in the future. It is safest to write scripts using ‘--mask_condition’.