Rascat - concatenate, convert raster files
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... ]
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.
- -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.
- 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.
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
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 (C) 1987-2009
University Corporation for Atmospheric Research
The use of this Software is governed by a License Agreement.