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.help wtextimage Oct93 dataio
.ih
NAME
wtextimage -- convert an IRAF image to a text file
.ih
USAGE
wtextimage input output
.ih
PARAMETERS
.ls input
An IRAF image file name or template of file names to be converted.
.le
.ls output
Name or root_name of output text file. If more than one IRAF image
is being converted, the ordinal of the file in the input file list
is appended to \fIoutput\fR to generate a unique output file name.
.le
.ls header = yes
This parameter determines whether or not a descriptive header precedes
the pixels written to the text file. When \fIheader = no\fR, only
pixels values are converted; no header information is included in the
output.
.le
.ls pixels = yes
This parameter determines whether or not to write the pixels to the
text file. This can be set to no to only write out the header.
.le
.ls format = ""
Output format for each pixel. If not set by the user, the appropriate output
pixel format is determined by the image data type.
Acceptable formats are chosen from "W.D[defgz]" where w is the field width and
d specifies the precision. Fortran formats of the form [iefgz]W.D are also
acceptable. If a field width of 0 is specified, (e.g., 0.6g),
output will be free format with each output line containing as many pixels as
will fit on the line. This is the most space efficient format but requires
that the reader program be able to handle free format (list directed) input.
.le
.ls maxlinelen = 80
The maximum number of characters output per line of text; \fBmaxlinelen\fR
must not exceed 322 characters. (Note that tasks \fIrtextimage\fR and
\fIwcardimage\fR cannot read lines of text greater than 161 characters.)
.le
.ih
DESCRIPTION
IRAF images are converted to text files with procedure \fBwtextimage\fR.
The text file written consists of an optional header optionally followed by
the pixel values. The pixels are output in FITS order, that is, the
leftmost subscript varies most rapidly. The image header is written in the
"keyword = value / comment" format of FITS.
.ih
EXAMPLES
1. Write a text file from an image section of dev$pix. The default maximum
linelength of 80 is used; an output format is specified. The header portion
of the output text is as follows:
.ls
.nf
BITPIX = 8 / 8-bit ASCII characters
NAXIS = 2 / Number of Image Dimensions
NAXIS1 = 10 / Length of axis
NAXIS2 = 10 / Length of axis
ORIGIN = 'NOAO-IRAF: WTEXTIMAGE' /
IRAF-MAX= 31431. / Max image pixel (out of date)
IRAF-MIN= 33. / Min image pixel (out of date)
IRAF-B/P= 16 / Image bits per pixel
IRAFTYPE= 'SHORT INTEGER ' / Image datatype
OBJECT = 'NGC 4147 B 1800 ' /
FILENAME= 'DEV$PIX[1:10,1:10]' / IRAF filename
FORMAT = '11I7 ' / Text line format
DATA-TYP= ' object ( 0 )' / object,dark,comp,etc.
ITIME = 1800 / integration time secs
UT = '11:23:13' / universal time
ZD = '24: 5: 0' / zenith distance
DATE-OBS= '15/02/1985' / dd/mm/yy observation
ST = '13:38:31' / sidereal time
RA = '12: 9:20' / right ascension
DEC = '18:35:35' / declination
EPOCH = .0 / epoch of RA and DEC
CAM-TEMP= -104.95 / camera temperature, deg C
DEW-TEMP= -192.96 / dewar temp, deg C
HISTORY1= 'bt= 590 bp= 0 cr= 0 dk= 0 '
HISTORY2= 'ff= 55 fg= 0 sc= .000 bi= 51 '
COMMENT = 'ngc 4147 b 1800'
F1POS = 2 / filter bolt I position
F2POS = 0 / filter bolt II position
END
.fi
.le
2. Write a series of text files from the IRAF images having root name
"reduced". One text file is written for each image.
cl> wtext reduced.* txt
.ih
TIME REQUIREMENTS
It takes almost 10 cpu minutes to convert a 512 square image of real pixels.
A 512 square image of integer pixels takes about 3 cpu minutes.
.ih
SEE ALSO
wcardimage, rtextimage, noao.onedspec.wspectext
.endhelp
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