PARAMETERS · EXAMPLES · BUGS · SEE_ALSO
strfits -- Convert FITS files to GEIS images, STSDAS tables or text files
strfits input file_list output
The `strfits' task reads standard FITS files containing main FITS units and extensions like "TABLE", "BINTABLE" and "IMAGE" -- from either disk or tape -- and converts them to GEIS files, STSDAS tables, or text files.
The `strfits' task can also read files in the IEEE standard format. FITS data written in IEEE standard will be converted to images in the floating point format of the host machine. The IEEE standard is denoted in the FITS header by a negative "BITPIX" value.
If you want to reproduce a GEIS file with a specific group parameter descriptor, then use the "template" parameter with the name of a GEIS image header file; the program can reproduce the specified output image with the same group parameter descriptor as the one specified by "template". If no template is passed to `strfits', then a default descriptor is set up in the image header that contains the fields "DATAMAX", "DATAMIN", "CRPIXn", "CRVALn", and "CDn_m". A warning will be issued if there is no data file corresponding to the template file name; however, this warning can be ignored because only the header file is needed.
WARNING: the IRAF tasks `rfits' and `wfits' in the `dataio' package are NOT designed to handle multi-group GEIS files or binary tables. Users should be aware that these IRAF FITS tasks may not produce data structures that are compatible with certain STSDAS tasks!
Notice that when using a template header with an input FITS file, you are matching the name of the keywords that belong to the group parameter block; your FITS header should have the name and value of those keyword in the template file, for each FITS file you are reading.
The FITS long blocks option is supported---up to 10 blocks of 2,880 bytes. If "SIMPLE=F", a warning message is printed to the standard output.
The `stwfits' task can write a multigroup image to a FITS file that will contain an extra dimension to accommodate the groups. This file will have the keywords "OPSIZE" (which takes its value from the input image keyword "PSIZE") and the keyword "SDASMGNU", whose value is the number of groups in the input multigroup image.
If the input FITS file includes the above keywords, then setting the parameter "xdimtogf=yes" will recreate the original multigroup file. If no such keywords exist a warning message: "Warning: FITS file cannot be converted to multigroup" will be issued.
- fits_files [file name template or magtape device]
- The FITS data source. This is either a template describing a
list of disk files, or a tape file specification of the form
"mt*[n]", where "mt" indicates a magnetic tape device, "*"
represents a density, and "[n]" is the tape file number to be
read. If the tape file number is specified, only that file is
converted. If the tape device name is given without a tape
file number, e.g., "mta" or "mtb800", then the files
specified by the `file_list' parameter will be read from the
If you want to use an input tape you will need to allocate it
before running `strfits', this can be done with the `allocate'
command, for example, "allocate mta".
For disk FITS files that contain extensions and want to extract an specified extension; you can do so by appending extension number after the name, e.g. "disk_file.fit" will extract second extension in "disk_file.fit"; disk_file.fit will extract the main FITS unit only. Warning: This facility is available with one input FITS file at a time, (i.e. you cannot specify a list as input).
- file_list [string]
- The files to be read from a tape. This string can consist of any sequence of file numbers separated by at least one comma or dash. A comma separates individual file numbers, whereas a dash specifies a range of files. For example the string "1,2,3-5,8-6" will convert tape files 1 through 8.
- iraf_files [string]
- The IRAF file that is to be created from the FITS data. This can be a
single file name, a list file (e.g., "@flis") or the null file (i.e.,
""). When handling multiple files, this parameter will be used as a
prefix and the file number will be appended. If only a single file is
being converted, the file will be named as specified. For example,
reading files 1 and 3 from a FITS tape and using a file name of "data"
for this parameter will produce the files "data001" and "data003". If
the disk or tape files contain more than one table per file then this
parameter will be used as a root name and a sequential number will be
appended to it, e.g., "tab01.tab", "tab02.tab" and "tab03.tab" will be
created when 3 tables are contained in one file.
If the FITS file contains a TABLE extension, the filename in the EXTNAME keyword has one of the recognized ASCII extensions and only a single column, the resulting iraf file will be an ASCII file. The recognized ASCII filename extensions are trl, txt, log, ocx, pdq, pod, cmh, trx, rpt, cgr, dgr, dta, poa.
- (template = "none") [string]
- This is the header file (a data file is not needed) containing the group parameter descriptor for the output GEIS file. See the Description section above for more information. For this parameter to be read you need to set xdimtogf=no.
- (long_header = no) [boolean]
- Print the full FITS header on the standard output?
- (short_header = yes) [boolean]
- Print shortened headers on the standard output? If
"short_header = yes", the task will print one line
information with the following columns:
IRAFNAME Output image name DIMENSION Image dimensionality BP Output image bits/pixel DATE Creation date OBJECT Content of OBJECT FITS keyword
- (datatype = "default") [string]
- This is the data type for the IRAF image file, which may be a
different data type than the FITS image file.
The allowed values are "unsigned" (16bits), "short", "integer", "real", and "double". Truncation problems may occur if an inappropriate data type is specified. Incorrect data types or null strings in this parameter will cause the default datatype to be used. The default data type is determined by the minimum size required to represent the input pixel values. If the "bscale" and "bzero" parameters in the FITS header are undefined, or if "bscale=1.0" and "bzero=0.0", then the data type will be either short or long--otherwise it will be real.
- (xdimtogf = yes) [boolean]
- Convert an extra dimension FITS file to a multigroup image
To do this you should have written the FITS file with the task `stwfits'. For more details see the Description section above.
- (scale = yes) [boolean]
- Scale the data based on the values of `bscale' and `bzero'?
This parameter is also used to scale the FITS extension. For
types "TABLE"and "BINTABLE" it will apply the values of TSCAL
and TZERO to the data in the respective columns.
If "scale = no", then the integers are read directly from the tape, otherwise the program checks the values of "bscale" and "bzero". If these numbers are not 1.0 and 0.0, respectively, the program scales the data before output.
- (blank = 0.0) [real]
- The IRAF image value of a blank pixel.
- (offset = 0) [integer]
- This parameter specifies the offset to be used in assigning a name to the resulting GEIS file. For example, if "offset = 100", `iraf_file = "fits", and `file_list = "1-3", the output file names will be "fits101", "fits102" and "fits103" rather than "fits001", "fits002", and "fits003".
- (oldirafname = no) [boolean]
- When restoring images to disk, should the task use the old file
name from the header and restore the file's original name? The
old file name is in the keyword value "FILENAME" or "IRAFNAME".
If FITS "TABLE" or "BINTABLE" extensions are present, the program
will try to restore the table to disk using the filename defined
by the "EXTNAME" keyword in the standard extension FITS
parameter header. If the `output' parameter is NULL (i.e., "")
or the FITS file does not have an extension, the filename
extension will be taken from the "imtype" CL variable; if
"imtype" is undefined, the extension will be set to "hhh".
If the `output' parameter value has a root plus an extension,
the extension takes precedence over the "imtype" value.
If FITS IMAGE extensions are present, the program will try to restore the GEIS image(s) to disk using the filename defined by the FILENAME keyword.
- (force = no) [boolean]
- There are certain fits files which strfits cannot convert, because the fits standard is more general than either the geis or tables standard and some fits files have no representation as either type of file. Generally these are fits files with extensions that were not originally converted from images or tables. Strfits tries to detect thes files and leave them as fits files, but sometimes it guesses wrong and leaves a file unconverted which should have been converted. If this task parameter is set to `yes', strfits will try to convert all files into either an image or table. But it may not succeed, and may crash in the attempt.
1. Convert a set of FITS files on tape to a set of IRAF image files, allowing the program to select the output data type. Blanks will be set to zero. Notice that there is no explicit extensio in images, the value of imtype will be taken.
cl> strfits mtb1600 1-999 images if imtype is 'imh' then you will need to add 'xdim-' cl> strfits mtb1600 1-999 images xdim-
2. Convert a set of FITS files on disk to a set of IRAF images with the image type set to GEIS (".hhh").
cl> set imtype=hhh cl> strfits fits* 1 images
3. Convert a set of FITS files directly to IRAF images without scaling.
cl> strfits mtb1600 1-999 images scal-
4. Convert the first three FITS files on tape to IRAF files setting blanks to -1.
cl> strfits mta 1-3 images blan=-1
5. Create a GEIS file with a non-default group parameter descriptor contained in file "fi_template.hhh". Notice that xdimtogf is set to no.
cl> strfits file.fits "" images xdimtogf=no \ >>> template="fi_template.hhh"
6. Create a multigroup image (GEIS file) from a set of input files using a template file containing the group parameter descriptor. Notice that you cannot use wild card specifications for the input FITS file and that the template header file is only needed when creating the multigroup file the first time.
cl> set imtype=hhh cl> strfits file1.fits "" outf.hhh[1/3] \ >>> template="file_temp.hhh" xdimtogf=no cl> strfits file2.fits "" outf.hhh cl> strfits file1.fits "" outf.hhh
7. Same as example 6, but with the input from tape.
cl> strfits mta 1-3 outf[1/3] template="file_temp.hhh" \ >>> xdimtogf=no or cl> strfits mta 1 outf[1/3] xdimtogf=no \ >>> template="file_temp.hhh" cl> strfits mta 2 outf cl> strfits mta 3 outf
Notice that the tape fits files 1 thru 3 should have the same physical specification, i.e., the same dimensionality and same number of group parameters. Also, if you create a multigroup file -- like in examples 6 and 7 -- you cannot also specify `oldirafname=yes'.
8. Read 4 FITS files from tape and create one GEIS image with 4 groups. Assume the FITS files contain WF/PC data. Use a template file with a GEIS WF/PC header file, e.g., twfpc.hhh.
cl> strfits mta 1-4 newpfc.hhh[1/4] template="twfpc.hhh" \ >>> xdimtogf-
Notice that you need to tell strfits that the resulting GEIS file will have 4 groups and that you are starting with group 1. The xdimtogf is set to "no" since you don't have a FITS file with an extra dimension.
9. Read 3 FITS files from tape and create 3 GEIS files with names in the list file outlist.
cl> strfits mta 1-3 @outlist
The BINTABLE extension is limited to 1 element per cell on a table. The program cannot yet read images that have excessively long lines because the image I/O has memory allocation restrictions. Blank pixels are counted and set to a user-determined value, but are not flagged in the image header.