DEVICE specifies the graphics device:
device | name | xsize ; ysize | color type
The following graphics devices are available:
XW X Windows terminal
NC NTRANS Computer Graphics Metafile
GF GIF file using X-server
GIF GIF file not using X-server
UTF Universal Transmission Format (AFOS)
RBK AWIPS RedBook Graphics
VG Vector Graphics (N-AWIPS Product Generation)
XWP Combination driver
FAX Fax driver
TIFF TIFF file
The following three PostScript device names are included for backward
compatibility only. The appropriate settings for the PS device are
automatically selected based on the information below.
PS1 PostScript - Landscape / Letter / Monochrome
PSC PostScript - Landscape / Letter / 32 Colors
PSP PostScript - Portrait / Letter / 20 Grays
The XWP driver combines the capabilities of several drivers. Currently,
it includes the XW and the PS drivers. XWP allows the user to display
graphics to a window, then, without closing the window, a PostScript file
may be created.
The UTF driver produces output for AFOS devices and the NAFOS product.
Note that while both AFOS and NAFOS read files in universal transmission
format, the exact file formats for are not compatible. The default
output is to an AFOS formatted file. The color control (see below) is
used to switch between output types.
The RBK driver produces output for AWIPS devices and OSO products. These
products are created according to the Standard Formats for Weather Data
Exchange format. However, the OSO format has an extra transmission header
information section. The default file is of an OSO format. The color
control (see below) is used to switch between output types.
The FAX driver produces an NMC 6 bit formatted file.
The TIFF driver produces a TIFF file that uses the Group 4 Fax
compression scheme. It can also optionally create a file with no
The VG driver produces a GEMPAK Vector Graphics file. This file can then
be used in product generation for graphical editing of the elements.
When producing a VG file, CLEAR has no effect, i.e., all elements are
added to the output file regardless of the value of CLEAR.
NAME is the file or window name. In the NC driver, if the file already
exists, new frames will be appended to it unless the default file name
of Nmeta is used. In this case, the file is overwritten. The PS driver
also uses the file name to generate plot files, however no appending is
attempted. Files are always overwritten. In the XW or XWP drivers, up to
five named windows may be opened.
If no file/window name is given, the following will be used:
FAX 999X;0167 (produces the file 999X.6bt)
The UTF driver defaults to an AFOS test product PIL if no entry is given.
The file name may be the last three characters of a valid PIL, or a full
file name. If the file name is a PIL, the product table is read for
specific size and time attributes. If a regular file name is given,
suitable defaults are chosen for the size and forecast time. The user
may also give a base time for the product. This is added to the file name
following a semi-colon, i.e., "T01;1200". This product would have a base
time of 1200 GMT. The forecast hour read from the product table is added
to the base time to give a valid time for the product.
The RBK driver defaults to an OSO formatted file if no entry is given.
The file name must be the last three characters of a valid AFOS PIL, or
the test PIL id, T01. The PIL id is used by the product table to find the
specific size and time attributes. The difference between the AWIPS format
and the OSO format is the information given at the beginning of the file
and that the AWIPS format does not have any padding of spaces at the end of
the file. Similar to the UTF driver, the user may also give a base time
for the product. This is added to the file name following a semi-colon,
i.e., "93E;311200". This product would have a base date of the 31st and a
base time of 1200 GMT. The base date may also be given in the full GEMPAK
date/time format, i.e., "9JH;000931/1200". The forecast hour read from
the product table is added to the base time to give a valid time for the
product. If the base date or time is not specified, then the system date
or time will be used for the valid time.
The FAX file name entry equates to a wheel and subset for the output
product. Every fax product must have an associated wheel and subset
number. The driver uses the supplied wheel and subset number to determine
the dimensions of the product. These dimensions are defined in the
product table, faxprod.tbl. This file will be named "XXXX.6bt" where
XXXX represents the wheel number of the product. The subset number is
embedded in the compressed 6 bit image and is only meaningful to OSO
systems that transmit products.
The TIFF file name entry is the WMO ID of the product. The driver uses the
supplied ID to determine the dimensions of the product. These dimensions
are defined in the product table, tiffprod.tbl. The output file will be
named "AAAAII.tiff" where AAAAII represents the 4 character and 2 digit
WMO ID of the product.
XSIZE and YSIZE are the device dimensions. The specification of their
values is a function of the device driver.
For XW or XWP, xsize and ysize may be (1) the number of pixels in the
corresponding direction if the values are specified as integers, or (2) a
fraction of the screen size if the values are specfied as reals > 0 and
< = 1.
For the PS driver, xsize and ysize are the paper dimensions in inches. If
xsize is greater than ysize, then a landscape orientation is used. For
xsize less than ysize, the plot orientation is portrait.
For UTF driver, xsize and ysize have no meaning, as the dimensions for the
display are determined by the entry on the product table (product.tbl)
that matches the user supplied pil.
For the NC driver, xsize and ysize are fractions of the maximum dimension
of a NTRANS CGM file. Their values must be > 0 and < = 1. If both values
are less than 1, then the larger value is set to 1 and the smaller value
is increased proportionally to maintain the aspect value of the user
If xsize and ysize are not specified the following defaults will be used:
XWP .7;.7 (70 percent of the screen size)
XW .7;.7 (70 percent of the screen size)
PS 11;8.5 (Standard letter size paper in landscape)
NC 1.0;1.0 (Standard square CGM plotting space)
COLOR TYPE is a flag for specifying the color scheme to use for the
driver. Currently, only PS will use the color type. Color type may have
the following values:
C 32 Colors
G 20 Grays
M Monochrome lines with color fills
The default is to use 20 grays. The exceptions to this are noted below.
For UTF (which is a monochrome device), a value of C is used to switch the
output to an NAFOS formatted file. Any other value for color type results
in an AFOS formatted file.
For RBK (which is a monochrome device), a value of C is used to switch the
output to an AWIPS formatted file. Any other value for color type results
in an OSO formatted file.
For TIFF, the default is monochrome output with a white background and all
graphics drawn in black. This type of output will be compressed using the
Group 4 Fax compression scheme. A value of G will create an output file
that has a black background with all graphics drawn in white. It will also
allow a grayscale image to be written to the output file. This type of
output will not be compressed.
The GF driver has the same options as the XW driver. The differences in
execution are that the GF device will not display a graphics window, and
will create a separate file for each active frame either when the device
is closed or a new file name is given. The file names are based on the
user supplied file name, with the frame number appended to the name after
the initial file has been created. That is, given the default name, the
first GF file created will be named "gempak.gf", the following file will
be named "gempak.gf.001".