WXP
Program Reference

nids2image

Sections

NAME

nids2image - NIDS data to image file

SYNOPSIS

nids2image [parameters...] filename

PARAMETERS

Command Line Resource Default Description
-h help No Lists basic help information.
-df=filename default wxp.cfg Sets the name of the resource file.
-na=name name nids2image Specifies the name used in resource file parsing.
-me=level message out2 Specifies level of messages to be displayed
-fp=path file_path the current directory Specifies location of database files.
-dp=path data_path the current directory Specifies the location of the input raw data files.
-cp=path con_path the current directory Specifies location of decoded/converted data files
-nc=name_conv name_conv name.cnv or name_conv file This sets which name convention file to use.
-if=in_file in_file None Specifies input file name tag. If not specified, the program will use the stations in the rad.cty file. If specified, this points to the list file with all the stations in it. See list file description below.
-of=out_file out_file program specific Specifies the output file name tag.
-cu=[hour] current none This specifies to use current data files.
-ho=hour hour none Specifies the exact hour that a data file is valid for.
-pd=domain plot_domain ps,38.5,-98,700,500,.08,.08 Specifies the location and size of output image
-cf=filename city_file rad.cty Specifies the name of the city database file
-nf=in_file nids_file nids_n0r Specifies the input file name tag for NIDS data.
-th=val,val,... threshold -100,0-70/5 Specifies the cutoff values for converting values to an image.
-pm=tag prec_mask prec_mask.grd Specifies the file name tag for the winter precipitation mask
-ti=title title none Specifies the title to describe the output image as in "Base Refl Mosaic [dBZ]".
-pa=param[,param...] parameter none Specifies additional parameters to the program:
  • noclar - remove all sites in clear air mode
  • interp - interpolates the value from the nearest 4 points from the NIDS data. Otherwise, the program uses the nearest value
  • crad=radius - remove all echoes inside this radius in km to site
  • ramp=max,radius - use a linear ramp function to remove echoes below a certain value. The linear ramp has a max at radius 0 and a radius in km at which the filter value drops to 0
filename (positional) filename none Specifies a list of files to incorporate into the mosaic. If the file ends in ".lst", it specifies a list file. See list file description below.

DESCRIPTION

This program mosaics NIDS level 3 data into a rastor image. The program takes either radial or rastor NIDS data and remaps it to a grid specified by the resrc:plot_domain resource. Once remapped, it applies the data to the output grid. The maximum value for a grid point is saved. Once all specified NIDS data is incorporated into the grid, the data are saved to an image file. The conversion from value to image pixel is done with the resrc:threshold resource.

By default, the program incorporates all the sites in the rad.cty file with a priority at 3 or lower. It does not include sites from Alaska, Hawaii, Puerto Rico or Guam.

Threshold

The threshold is a list of cutoff values for the image. The threshold values are separated by commas. A range of values can be specified as low,high/delta. So a range from 0 to 75 with a interval of 5 could be specified as 0-75/5. The first value listed will get mapped to pixel value 0 in the image. The next one will get 1 and so on. But since the output file will be a valued image, the values are all that need to be known to process the image. If the threshold contains values above 80 and less than 180, this are considered mixed precip values (winter mosaic). If the values run from 180 to 280, these are for frozen precipitaion.

Winter mosaics

Since NIDS data doesn't have rain and snow modes, there is no way to produce a winter radar mosaic directly from the NIDS reflectivity data. To do this, first a precipitation mask grid needs to be created. The prog:radmask program will use the "RAP" model to produce this grid. The grid has values of 0 for rain, 1 for mixed and 2 for frozen precipitation. Typically, this grid file will have a date time stamp in the filename. So to access the proper precip. mask grid, specify the name convention of the file with the resrc:prec_mask resource.

Clutter / AP filtering

The program uses two simple filter mechanisms:

The point of the ramp filter is that in most cases, AP is the worst near the site and diminishes roughly linearly the farther you get away from the site. A value for all sites can be specified with the parameter resource.

List files

The list file is a file that contains a list of sites to be incorporated into the mosiac. Each line is a different site. The line contains:

name [flag] [param]

The name is the filename or the name convention tag. The optional flag is either a 0 or 1 depending on whether to include the site or not. The param is a parameter such as crad or ramp so that these can be specified on a site by site basis. This can be a static file or can be generated by the prog:radmask program. The radmask program will generate custom ramp parameters for each site based on model data. This is the preferred method. Here is a sample list file:

nids:t=n0q:i=ABR ramp:25:250
nids:t=n0q:i=ABX ramp:15:150
nids:t=n0q:i=AKQ ramp:40:400
nids:t=n0q:i=AMA ramp:35:350
nids:t=n0q:i=AMX ramp:40:400
nids:t=n0q:i=APX ramp:30:300

If the list file is generated by the radmask program, use a name convention that includes date. This name convention will then be specified in the resrc:in_file resource.

Program execution

This program should be run on a regular basis from cron. Tyipcally, it's run every 5 or 6 minutes.

EXAMPLES

FILES

SEE ALSO


Last updated December 2013