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:
|
| 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:
- Clutter radius - this drops all echoes inside a certain radius in km.
- Ramp filter - this uses a linear algorithm removing echos below a certain value based on the distance from the site. This is given with a maximum value which the filter value at the radar site, and a distance in km which is the point at this the filter value drops to 0.
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
nids2image -if=bref_list -pd=us02 -of=rad_wxpmos -pa=interp -th=-100,-10-70/2,90-150/2,190-250/2 -pm=winmask -ti="Reflectivity mosaic [dBZ]"
This specifies to use the bref_list name tag for the input list file. The mosaic will be created from the sites listed in that list file. The output will be on a grid specified by the "us02" domain. This is a 2km mosaic domain. The output will be saved into a file with the "rad_wxpmos" name tag. The "inter" parameter is set which will interpolate each value on the grid from the 4 nearest NIDS points. The threshold parameter states to create a mosaic with a 2dBZ interval with allowances for winter parameters. The winter mask is in a file with the "winmask" name tag. The output image will have a label of "Reflectivity Mosaic [dBZ]".
FILES
- rad.cty - the radar station location database file
SEE ALSO
Last updated December 2013