axVec: Generate axis vector for image
In FITSio: FITS (Flexible Image Transport System) Utilities

Description Usage Arguments Details Value Author(s) References See Also Examples

axVec generates a vector of axis values from variables contained in a FITS image file header.

1	axVec(nax = 1, axDat)

`nax`	index number of the axis.
`axDat`	data table axis variables produced by `readFITSarray` (which is also contained in `readFITS`).

Run once for each axis needed.

A vector with length equal to the number of pixels along the axis. Vector values v[i] for i = 1:NAXISn (NAXISn = len, the vector length, in the axDat data frame) are:

v[i] = (i - CRPIXn) CDELTn + CRVALn

where CRPIXn, CDELTn, and CVALn are the reference pixel, pixel increment, and reference pixel value for each axis n, following the FITS standard.

Andrew Harris

Hanisch et al., Astron.\ Astrophys. 376, 359-380 (2001)

https://fits.gsfc.nasa.gov/

readFITS, readFITSarray

require(FITSio)
Z <- matrix(1:15, ncol = 3)
filename <- paste(tempdir(), "test.fits", sep="")
writeFITSim(Z, file = filename, c1 = 'Test FITS file',
            crpix = c(1,1), crvaln = c(10, 100), cdeltn = c(8, 2),
            ctypen = c('Distance', 'Time'),
            cunitn = c('Furlongs', 'Fortnights'))
X <-  readFITS(filename)
ax1 <- axVec(1, X$axDat)
ax2 <- axVec(2, X$axDat)
xlab <- X$axDat$ctype[1]
ylab <- paste(X$axDat$ctype[2], " [", X$axDat$cunit[2], "]", sep = "")
image(ax1, ax2, X$imDat, xlab = xlab, ylab = ylab)

## Clean up files to avoid clutter
unlink(filename)