The Gen-Vx-Mask tool may be run to speed up the execution time of the other MET tools. Gen-Vx-Mask defines a bitmap masking region for your domain. It takes as input a gridded data file defining your domain and a second argument to define the area of interest (varies by masking type). It writes out a NetCDF file containing a bitmap for that masking region. You can run Gen-Vx-Mask iteratively, passing its output back in as input, to define more complex masking regions.
You can then use the output of Gen-Vx-Mask to define masking regions in the MET statistics tools. While those tools can read ASCII lat/lon polyline files directly, they are able to process the output of Gen-Vx-Mask much more quickly than the original polyline. The idea is to define your masking region once for your domain with Gen-Vx-Mask and apply the output many times in the MET statistics tools.
View the usage statement for Gen-Vx-Mask by simply typing the following:
|input_file||Gridded data file defining the domain|
|mask_file||Defines the masking region and varies by -type|
|out_file||Output NetCDF mask file to be written|
|[-type string]||Masking type: poly, box, circle, track, grid, data, solar_alt, solar_azi, lat, lon, shape|
|[-input_field string]||Define field from input_file for grid point initialization values, rather than 0.|
|[-mask_field string]||Define field from mask_file for data masking.|
|[-complement, -union, -intersection, -symdiff]||Set logic for combining input_field initialization values with the current mask values.|
|[-thresh string]||Define threshold for circle, track, data, solar_alt, solar_azi, lat, and lon masking types.|
|[-height n, -width n]||Define dimensions for box masking.|
|[-shapeno n]||Define the index of the shape for shapefile masking.|
|[-value n]||Output mask value to be written, rather than 1.|
|[-name str]||Specifies the name to be used for the mask.|
|[-log file]||Outputs log messages to the specified file|
|[-v level]||Level of logging|
|[-compress level]||NetCDF compression level|
At a minimum, the input data_file, the input mask_poly polyline file, and the output netcdf_file must be passed on the command line.