The ascii format is basically as follows: each record, with line length reclen (excluding the newline), consists of a small header followed by nchan values of the spectrum. The header must at least contain the pointing position, glon and glat, and sometimes variables that are only known to the decoding routines (see decode.f). All values in the header are integers, typically 10 times or 100 times, the actual real value, but this is certainly no requirement. It merely saves space.
Here are some properties of the available surveys from $HI_DIR:
id reclen nrec nchan Survey Authors Source hh 643 134932 100 Hat Creek High-Latitude (Heiles+ 1974-1976) ADC 8007 pk 420 9891 64 Parkes High-Latitude (Cleary+ 1979) ADC 8008 ar 396 55470 56 Argentina High-Latitude (Colomb 1980) ADC 8009 bl 703 22261 124 Bell Laboratories (Stark+ 1990) ADC 8010 ww 1204 38961 238 Berkeley Low-Latitude (Weaver, Williams 1973) ADC 8011 jo 1314 38961 260 Berkeley Low-Latitude (Weaver, Williams 1973) JO fits kj 1514 17901 300 Parkes Southern Low-Latitude (Kerr+ 1986) JO fits lb 1130 1842 224 Galactic Center (Burton, Liszt, 1983) Liszt fits
Some telescope properties, in particular the conversion from antenna temperature
to brightness temperature, are:
id beam spacing spacing TA/TB (deg) (deg) (km/s) conversion hh 0.5 0.5 2 : ? Hat Creek 26m (85ft) pk 0.5 0.5 2 : ? Parkes 64m (210ft) ar 0.5 2 4 ? PPI 30m bl 2 2 5.2767 ? 7m Bell Labs ww 0.5 0.25 1.055 ? T_A Hat Creek 26m (85ft) jo 0.5 0.25 1.0 ? T_A Hat Creek 26m (85ft) kj 0.5 0.25 1.0 0.975 T_A Parkes 18m lb 0.5 0.5 2.75 0.66 NRAO 140ftCurrently
# ADC tape 1, skip the software, and read the data mt -f /dev/rmt12 fsf 1 dd if=/dev/rmt12 of=hh.hi ibs=8464 cbs=643 conv=unblock dd if=/dev/rmt12 of=pk.hi ibs=8464 cbs=420 conv=unblock dd if=/dev/rmt12 of=ar.hi ibs=8464 cbs=396 conv=unblock ? dd if=/dev/rmt12 of=bl.hi ibs=14060 cbs=703 conv=unblock # ADC tape 2, skip the software, and read the data mt -f /dev/rmt12 fsf 1 dd if=/dev/rmt12 of=ww.hi ibs=12040 cbs=1204 conv=unblock # JO fits files fitstohi in=fits id=482:702:1 lon=240:350:0.5 out=kj.hi cdelt1=1000 # BL fits cube fitstohi in=hicenter.vlb out=lb.hiThe conv=unblock causes a newline to be inserted after each record, such that (in principle) fgets(3S) and wc(1) can be used for processing (but see BUGS below).
On a VMS system the DUMP_NSDC program (generally found in the first file on the ADC tape) can be used to convert (ADC) tape data into a disk file.
The ww seems to contain bad data for L=11.5, 29 and 91.5. Use jo instead, which has been derived from the equivalent VB-FITS files.
Ra and Dec are not known for the WW, LB and KJ datasets.
If you modify/add a new dataformat, you have to modify hi.h, decode.f and the switch-table in hispectrum.c. This should have been clearly isolated to one routine.
LB: The original data from H.S.Liszt (hicenter.vlb) is a FITS cube of spectra in l and b, with the velocity axis specified in m/s. Reference: W. B. Burton and H. S. Liszt, 1983 A&A Suppl 52, p. 63.
KJ: The original data from P. Jackson consist of 221 separate VB fits files, each one at a different galactic longitude. Created by J. Ohlmacher and P. Jackson (11-dec-84) Reference: Kerr, F. J., Bauer P.F., Jackson, P.D. & Kerr, M., 1986 A&A Suppl 66, p. 373.
JO/WW: Gridded fits data are 481 separate VB fits file, each on a different galactic longitude. Created by J. Ohlmacher and P. Jackson (14-dec-81) Reference: Weaver, H. & Williams, D.R.W., 1974 A&A Suppl 17, p. 1.
PK Reference: Cleary, M. N., Haslam, C. G. T. & Heiles, C. 1979 A&A Suppl 36, p.95-127.
There is no implied guarantee that these routines will perform the tasks they claim. In other words, user beware--check the results before using them.
$HI_DIR/??.hi all ascii versions [200 Mb] $HI_DIR/??.hi.Z compressed ascii [49 Mb] $HI_DIR/??.hi.gz compressed ascii $HI_DIR/fits/hifits.* WW (1-481) and KJ (482-702) VB maps [33 Mb] $HI_DIR/fits/hicenter.vlb Burton & Liszt VLB cube [1 Mb] $NEMO/usr/pjt/hi NEMO programs source code
29-jun-92 V1.0: Created PJT 7-jul-92 documented all associated data PJT 8-apr-94 added JO dataset pjt 11-apr-94 renamed .raw extension to .hi pjt
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