Gen-Vx-Mask Functionality
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.
Gen-Vx-Mask Usage
View the usage statement for Gen-Vx-Mask by simply typing the following:
| Usage: gen_vx_mask | ||
| 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, poly_xy, 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, the output netcdf_file, and the type must be passed on the command line.
