Provided by: ncl-ncarg_6.6.2.dfsg.1-10build2_amd64 
NAME
Rascat - concatenate, convert raster files
SYNOPSIS
rascat [ -help ] [ -ifmt format ] [ -ira algorithm ] [ -ofmt format ] [ -output file ] [ -resolution
resolution ] [ -rgbscale scale-factor ] [ -scale scale-factor ] [ -verbose ] [ -Version ] [ -window nx ny
x y ] [ -pal palette_file ] [ -|file... ]
DESCRIPTION
rascat reads each file in sequence and copies its contents to the standard output performing any format
conversion and data massaging necessary as specified by the command line options. By default, rascat
determines the format of a file by looking at the file name extension. If there are multiple files input
into rascat with varying file formats rascat will perform format conversion such that the resulting
concatenated file will be in the format of the first file processed.
Input files must all have the same spatial resolution and have the same depth; 8-bit and 24-bit files may
not be intermixed. Furthermore, if an input file contains multiple images each image in that file must
have the same spatial resolution and be of the same depth.
Currently, only 8-bit-indexed and 24-bit-direct color encodings are supported.
See ras_formats(5NCARG) for a list of supported image formats.
OPTIONS
-help Print a usage message and exit.
-ifmt format
Specify the input file format. format is one of the file name extensions discussed in
ras_formats(5NCARG) (without the ".", e.g. xwd). When this option is specified file name
extensions are not necessary and are ignored if present. All input files must have the same
format.
-ira algorithm
Specify the image resampling algorithm to be used when either the -scale or the -resolution
command line option is used. algorithm may be either NN, indicating a "nearest neighbor"
algorithm, or BL, indicating a "bilinear interplation" algorithm. The default is to do "nearest
neighbor" interpolation.
-ofmt format
Specify the output file format. format is one of the aforementioned file name extensions. If used
in conjunction with the -output option the output file name requires no name extension and is
ignored if present.
-output file
Specify an ouput file name and possibly an implicit output format. By default rascat writes to the
standard output. When this option is used output is written to file. If the -ofmt option is not
specified file must have a file name extension recognized by rascat. In which case the file name
extension will determine the output format.
-resolution resolution
Resample the spatial resolution of input imagery to resolution, where resolution is the number of
pixels in the x direction, followed by an x, followed by the number of pixels in the y direction,
with no intervening spaces. For example, 512x512, specifies a 512 by 512 pixel resolution.
Warning: Aspect ratios are not preserved by this option. If the resolution of your input imagery
has a different aspect ratio then that specified by resolution the resultant image will be
distorted.
-rgbscale scale-factor
Specify a floating point scaling factor, scale-factor, to be applied to all the color intensities
contained in the input files. This option may be fairly computationally expensive with 24-bit-
direct encoded imagery.
-scale scale-factor
Specify a uniform, floating-point scaling factor to be applied to the spatial resolution of the
input files. Unlike the -resolution option this option guarantees to preserve the aspect ratio of
your imagery. For example, setting scale-factor to 0.5 causes your imagery to be resampled to one
fourth of its original spatial resolution. If its original resolution was 1024x1024 the resultant
resolution would be 512x512.
-verbose
Tells rascat to operate in verbose mode.
-Version
Print rascat's version number and then exit.
-window nx ny x y
Specify a subregion of the input imagery to be extracted. The area outside the rectangular
subregion defined by nx, ny, x and y is discarded. x and y specify the position of the upper-left
corner of the rectangle. nx and ny specify the rectangle's width and height, respectively.
-pal palette_file
Set the palette for the output rasterfile from palettefile, which can be either an HDF-type
palette with an extension of ".pal", or a textual palette with an extension of ".txt". See
ras_palette(5NCARG) for documentation on the formats. This option applies to indexed-color imagery
only.
ENVIRONMENT
NCARG_TMP
If set, this environment variable contains a directory path to be used for temporary files. On
most systems the default is /tmp. On some systems the default is /usr/tmp.
EXAMPLES
In the following example a NRIF file, a Sun raster image file, and a XWD file are concatenated and
converted into a single NRIF file:
% rascat file1.nrif file2.sun file3.xwd > file123.nrif
In this example the same files are converted and concatenated into a sun file:
% rascat -ofmt sun file1.nrif file2.sun file3.xwd > file123.sun
The -ofmt option is necessary in this example because the first file rascat encounters is an NRIF file.
Finally, in this example the upper left 512 by 512 rectangle of the file foo.sun is extracted and written
to the file foo.512x512.sun:
% rascat -window 512 512 0 0 foo.sun > foo.512x512.sun
SEE ALSO
rasgetpal(1NCARG), rasls(1NCARG), rassplit(1NCARG), rasview(1NCARG), ras_formats(5NCARG),
ras_palette(5NCARG)
Hardcopy: NCAR Graphics Fundamentals, UNIX Version
CAVEATS
Aspect ratios are not preserved by the -resolution option.
Not all formats support both 8-bit and 24-bit encodings.
Indexed and direct color encodings cannot be mixed.
COPYRIGHT
Copyright (C) 1987-2009
University Corporation for Atmospheric Research
The use of this Software is governed by a License Agreement.
NCARG January 1993 RASCAT(1NCARG)