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GRID

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NAME

grid - Raw file gridding and contouring program

SYNOPSIS

grid [parameters...] filename

PARAMETERS

Command Line Resource Default Description
-h help No Lists basic help information.
-df=filename default .wxpdef Sets the name of the resource file.
-na=name name grid Specifies the name used in resource file parsing.
-ba batch No Run program in batch mode
-me=level message out2 Specifies level of messages to be displayed
  • file information - mess
  • gridding information - out3
-fp=filepath file_path current directory Specifies location of database files.  
-dp=datapath data_path current directory Specifies the location (path) of the input raw data files. This may be modified in the name convention file.
-cp=conpath con_path current directory Specifies the location (path) of the input surface converted data files. This may be modified in the name convention file.
-rp=rawpath raw_path current directory Specifies the location of the output raw files generated by the program. These files will not be generated unless the out_file resource is specified and the output is plotted data.
-gp=gridpath grid_path current directory Specifies the location of the output grid files generated by the program. These files are not generated unless the out_file resource is specified and the output is a gridded field.
-ip=imagepath image_path current directory Specifies the default location of the output GIF images generated by the program.
-nc=name_conv name_conv name_conv The name convention file specifies how files are named in WXP. This sets which name convention file to use.
-if=in_file in_file raw Specifies the input file name tag. The default is raw, but it can be modified to any value in the filename convention file. A full name convention can be specified as well.
-of=out_file[,out...] out_file None Specifies what type of raw or grid file to create. By default, no output file is generated when the program is run. To produce an output file, this resource must be specified.  There are the following output file types:
  • wxp - WXP ASCII grid or raw file
  • wxpb - WXP binary grid file
  • raw - WXP ASCII raw file
  • cdf - NetCDF binary grid file

Second, the out_file resource specifies the output file name tag. The default is raw_grd but it can be modified to any value in the filename convention file. The file name tag can be specified separately or appended to the file type: wxp:sfc_grd

A full filename can be specified which can contain name convention tags.

-pf=file_param file_param User prompt
Batch: use
This specifies how to treat output files that exist:
  • Use - use the existing file, don't overwrite. The program terminates when this occurs.
  • Over - overwrite the existing file
  • App - append the information onto the end of the existing file
  • Y - same as overwrite
  • N - same as use.
-cf=cityfile city_file sao.cty Specifies the name of the city database file used in finding station locations.
-mf=mapfile[,...] map_file wxp.map or
cont.dat, country.dat for domains outside North America
Specifies the name of the map database file. Multiple maps can be specified along with attributes to describe how to draw the map.
-cu=[hour|la] current None This specifies to use current data files. The current filename is based on the name convention. An optional hour can be specified for older data. If la is specified, the program will search back to find the most recent available file.
-ho=hour hour None This resource specifies the exact hour that a data file is valid for. This locks in the start hour for a multi-file sequence.
-id=identifier identifier None Used to plot a specific observation. If not specified, all stations will be plotted.
-pd=domain plot_domain User prompt
Batch: first domain in wxp.reg file.
This specifies the plotting domain. The projection, aspect ratio and the domain size are specified.
-gd=grid_domain grid_domain Same as plot domain This specifies the domain to use when fitting data to a grid. If this is not specified, it is the plot_domain.
-re=region region Same as plot domain This resource is synonymous with the plot_domain.
-pr=prior stat_prior Depends on domain size This specifies the lowest priority to use in the plot. Priorities range from 1 to 7.
-oa=smooth[,radinf] [,passes] [,converg] [,min_sta] object_param 1,3,1,.2,1 Specifies the objective analysis parameters. There are 5 parameters including smoothing, radius of influence, number of passes, convergence parameter and minimum number of stations.
-pl=plot_type plot_type User prompt
Batch: fill contours or vectors
Specifies the type of output plot. By default, the user is prompted for the plot type. To produce a contour or vector plot, use the following plot types:

Contours:

  • cf -- color fill contours
  • ln -- line contours
  • dln -- dashed line contours
  • ndln -- negative dash line contours
  • lcf -- both line and color fill contours
  • gvalue -- plot gridpoint values

Vectors:

  • vect -- vectors/arrows
  • strm -- streamlines
  • barb -- wind barbs
  • none -- for no output plot
-sc=scale_factor plot_scale 1.0 Specifies a scaling factor for all plotted text, symbols, vectors, etc.
-fm=format plot_format None Specifies the output format of the plots.  This is generally used to specify how many decimal places get displayed on the plot and in the output raw files.
-pp=param[,param...] plot_param None Specifies additional plotting parameters. See the plot_param resource for more details.
-dr=drawable[,...] draw all Specifies which part of the plot is to be drawn.
-la=label[,...] label Program defaults Specifies the labels to be plotted around the plot. By default, labels are generated by the program and plotted above and below the plot. This resource overrides these labels.
-in=interval con_interval None for plots, User prompt for grids. Batch: 0 Specifies the contour interval to use in contouring grids. This can also be used to color code plotted data and vectors.
-cb=base con_base Lowest contour value, maximum wind speed Specifies the base value for color fill contours, and wind speed per grid distance. For more details, see the con_base resource.
-fl=font_list font_list modern.fnt Specifies a list of fonts to use in the plots.
-ct=color_table color_table wxp.clr Specifies the color table to use in the plot. This maps color names to actual RGB color values.
-cot=color[:attr] color_text white
black
for inverse plots.
Specifies the text color for labels above and below the plot.
-com=color[:attr] color_map red Specifies the color for background maps.
-coln=color[:attr] color_line magenta:st=dsh Specifies the color for lat/lon lines.
-cocm=color[:attr] color_cmap black Specifies the color for color fill contour maps.
-coco=color[:attr] color_cont white
black
for inverse plots.
Specifies the color for line contours.
-cof=[val:]color[:attr],... color_fill A predefined color set based on the wxp.clr color table Specifies the color fill contour color set. See the color_fill resource for more details.
-cola=color[:attr] color_label white
black
for inverse plots.
Specifies the line contour label color.
-cocl=color[:attr] color_clabel black Specifies the color fill contour label color.
-de=device[,...] device User prompt
Batch: display
Specifies the output device.
-ti=title title Program name Specifies the window title.
-ic icon Off Specifies whether to open window in iconified mode.
-bg=color background black
white for inverse plots
Specifies the background color of the window.
-ge=geometry geometry 640x480 Specifies the window and paper geometry.
filename[-field] filename None
User Pompt
Batch: none
The name of the raw file to be plotted. An optional sequence number can be added to designate the time for non-WXP files.

The extra information following the "-" defines which field to use within a raw file. The field specification can be a column number or a field identifier.   The field identifier is a string that accompanies a column header in the raw file or a string that precedes the data such as HGIRG=5.24

DESCRIPTION

This program grids and contours raw data on a background map. The input to the program is a raw file which can be produced by programs like sfcwx or upairwx programs. Then, based on a plot domain, a plot is generated.

The programs starts off by prompting the user for input raw file name.  The user may specify the input file either via the command line of through the current resource. The input naming convention is specified by the raw tag but this can be changed with the in_file resource.

In order to get specific information from a raw file, a field specifier can be appended to the filename.

filename[-field]

The field specification can be a column number or a field identifier.   The field identifier is a string that accompanies a column header in the raw file or a string that precedes the data such as HGIRG=5.24

Next, the program prompts the user for the plot domain. This is done through a region menu which has predefined regions available. If needed a full plot domain can be specified to get a precise domain. The domain can be interactively changed using the mouse once the plot has been generated.

After the region has been set, the city database is read in and a cross-reference table is setup. Since some raw data is not saved with location information, the program will refer to this table to location each station in the input file.

The program will now open the graphics window and start processing the data. The user will be prompted for the output device. Then the converted file is opened and data read in. Any additional computations are performed to produce a derived variable and fit the data to a grid. The background map will plot first unless the output is a color fill contour in which the map plots last. The gridding process uses an objective analysis scheme to produce the grids. The parameters for this process are specified in the object_param resource. Once the grids have been created, the maximum and minimum of the grid are displayed for the user to pick an appropriate contour interval. Then, the contour or vector plot will display.

There are several plot types.  For contour plots, there is:

  • ln - line contours
  • dln - dashed line contours
  • ndln - negative dashed line contours. All contours less than 0 are dashed. The breakoff can be reset with the con_base resource.
  • cf - color fill contours.  These are contours where the areas between the contour lines are filled with a progressive color scheme. By default, this is a 15 color scale in which the colors wrap around if there are more than 15 color level.  The color scheme can be set by the color_fill resource.

For vectors:

  • vect -- vectors/arrows
  • strm -- streamlines
  • barb -- wind barbs

When the plot is complete, output can be saved to a GIF image file, spooled to the printer or the plot can be zoomed.  When zooming the image, the plot will redraw to the new domain.  It will also add more stations to the plot depending on the size of the domain. When the user is finished with the plot, the enter key can be hit which closes the window and returns the user to the variable prompt.

Output Files

By default, this program does not produce output files.  If a raw or grid file output is desired, use the out_file resource to enable this.  By default, this will create a WXP ASCII raw or grid file depending on the plot type.  The out_file can be a filename, a file tag (lookup in file name convention file) or a name convention (with wildcards). The output can be GIF file by specifying gif as the file type. It may be desirable to turn plotting of when producing output files. To do this, specify none for the plot_type resource.

EXAMPLES

   grid -re=mw -pl=cf -in=2 -de=d temp.raw   

This produces a color fill contour plot of temperature for the midwest region at an interval of 2.

   grid -cu=la -re=mw -of=temp.grd -pl=none temp.raw

This will generate grid file temp.grd.

FILES

  • sao.cty - the surface station location database file

SEE ALSO

  • mapplt - the raw file plotting program
  • rawmath - the raw file mathematics program
  • contour - the grid file contouring program

For further information about WXP, email technical-support@weather.unisys.com
Last updated by Dan Vietor on Sept 28, 1997