Description Usage Arguments Details Value Note Author(s) References See Also Examples
Read a FITS binary table from an open connection to a FITS file.
1 | readFITSbintable(zz, hdr)
|
zz |
File handle; see Example. |
hdr |
Header card images, raw or parsed. |
readFITSbintable
reads the data from the binary table part of a FITS
Header and Data Unit (hdu) containing binary table data. The header must be
read first by readFITSheader
; either this header or the
parsed version from parseHdr
are valid for the hdr
variable. Binary tables are multi-column files with one or more rows. Each
column has an individual data type and number of entries per cell
(i.e., a cell may contain a scalar or vector).
64-bit integers are read as pairs of 32-bit integers, for a vector
twice the length of most other vectors. Files read properly, but
reconstructing the 64-bit representation is untested. The
CRAN package int64
may be of use here.
8, 16, 24, and 32-bit bit arrays return as integers. Other lengths are not supported.
Binary table complex and array descriptor data types are not implemented in this release due to a lack of examples for testing.
col |
Data from each column, either a vector or an array. |
hdr |
Vector with parsed header. |
colNames |
Vector of column names, TTYPEn FITS variable. |
colUnits |
Vector of column units, TUNITn FITS variable. |
TNULLn |
Vector of undefined value definitions, FITS variable. |
TSCALn |
Vector of multipliers for scaling, FITS variable. |
TZEROn |
Vector of zeros for scaling, FITS variable. |
TDISPn |
Vector of format information, FITS variable. |
Graphical FITS viewers such as fv (https://heasarc.gsfc.nasa.gov/ftools/fv/) and SAOImage DS9 (http://ds9.si.edu/) have excellent facilities for displaying FITS data, headers, and file structure. Having one or more graphical viewers available will prove extremely useful for working with FITS files, even when the data are read into R for further processing. fv and SAOImage DS9 are in active devlopement with support for unix, Windows, and Mac OS-X operating systems, and are available at no cost.
Andrew Harris
Hanisch et al., Astron.\ Astrophys. 376, 359-380 (2001)
readFITS
, readFITSheader
,
readFITSarray
, file
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | require(FITSio)
## Either download example file from
## <https://fits.gsfc.nasa.gov/fits_samples.html>
## and use
## Not run: filename <- "IUElwp25637mxlo.fits"
## or, for local example use
filename <- system.file("fitsExamples", "IUElwp25637mxlo.fits",
package = "FITSio")
## Open file, read header and table, close file.
zz <- file(description = filename, open = "rb")
header0 <- readFITSheader(zz) # read primary header
header <- readFITSheader(zz) # read extension header
D <- readFITSbintable(zz, header)
close(zz)
## Look at contents
str(D)
str(header)
str(parseHdr(header))
D$hdr[which(D$hdr=="BITPIX")+1] # BITPIX value from header
D$colNames
plot(D$col[[5]], ylab = "Value", main = D$colNames[5], type = "l")
|
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