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JuliaAstro / FITSIO.jl

Flexible Image Transport System (FITS) file support for Julia
http://juliaastro.org/FITSIO.jl/
MIT License
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Raw header for WCSLIB #39

Closed rgiordan closed 9 years ago

rgiordan commented 9 years ago

I'm looking into getting WCS information out of FITS image files, and it seems like the preferred function to use is wcspih, which, in WCSLIB.jl at least, requires a raw ASCII FITS header. I think this can only be accessed with the now private Libcfitsio.fits_hdr2str function.

I think this could also be done with wcsprm, but I haven't been able to find clear enough documentation about exactly which header key values should go into which arguments to do this with confidence.

Do you have thoughts about whether there is a better way to do this, or whether maybe the raw header string should be available to users for this reason?

kbarbary commented 9 years ago

I think it does indeed make sense to expose this FITSIO functionality in the high-level interface. How about adding a method read_header(hdu::HDU, ::Type{ASCIIString}) so that, e.g., 

raw_header = read_header(f[1], ASCIIString)

returns the header as a single string, rather than a FITSHeader object?

Ideally, in the future a wcsprm object could be constructed by passing any mapping-like object (e.g., Dict or FITSHeader) that contains WCS keywords. That's obviously a bit more work though.

rgiordan commented 9 years ago

Sounds good, let me try to put together a pull request.