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Eric Greisen wrote:
AIPS cannot handle HEALPIX but can someone ? There is FORTRAN, C and IDL code for reading HEALPIX FITS files available by registering at http://www.eso.org/science/healpix/. There is also a IDL image display program MAPVIEW available from the WMAP software library (http://lambda.gsfc.nasa.gov/product/map/m_sw.cfm). This can be run without an IDL license using the IDL virtual machine although this is somewhat cumbersome. Calabretta & Greisen (2002, A&A, 395, 1077) originally described HealPix as a pixelization which defines a distribution of points on the sphere but which does not relate these to points in a plane of projection and which therefore is outside the scope of WCS. But I was excited to see Mark Calabretta's recent preprint "Mapping on the HealPix Grid" available at astro-ph/0412607 which shows that Healpix *is* associated with a map projection, which will incorporated in V3.7 (not yet released?) of WCSLIB. I think this should eventually allow astronomical display programs (DS9, AIPS) to convert Healpix maps to any desired projection. The LAMBDA data center plans to increase its use of Healpix FITS files for CMB data, so it would be nice if these files were readable by the major display programs. --Wayne Landsman |
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Not sure if this is any help, but a google search on 'HEALPIX FITS' returns
links to a number of software packages that can read HEALPIX FITS files. -Bill Pence Eric Greisen wrote: AIPS cannot handle HEALPIX but can someone ? Eric Greisen ------- start of forwarded message (RFC 934 encapsulation) ------- From: Volker Heesen Sender: To: AIPS Cc: Subject: [daip] AIPS & HEALPIX Date: Fri, 07 Jan 2005 14:10:20 +0100 Hello, I would like to ask: Can aips handle HEALPIX-format files? Is there a possibility to transform HEALPIX to ordinary fits-files? Thank you! Regards, Volker |
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Hi,
Mark: I just read your paper on HealPix and I think your extension is great indeed. I have been working on a python port of the healpix software. That's not finished yet, but part of it is already useable. If there is interest I am willing to work it through and make it public. Andreas On 17.01.2005, at 05:31, Mark Calabretta wrote: On Thu 2005/01/13 13:47:05 CDT, Wayne Landsman wrote in a message to: with a map projection, which will incorporated in V3.7 (not yet released?) of WCSLIB. Should be released sometime soon. I think this should eventually allow astronomical display programs (DS9, AIPS) to convert Healpix maps to any desired projection. HEALPix data is best displayed in the HEALPix projection itself because no regridding is required, you see the data directly without potential artifacts introduced by regridding. All that is required is for a utility program to reorganize the 1-D vector (ring or nested) onto the 2-D grid. The HPX projection type can then be used to add a graticule and this can be saved as a 2-D FITS image and viewed with any software that understands FITS WCS (with HPX). However, such an image is presented with an odd 45 deg rotation (handled in the WCS via a PCi_j or CDi_j matrix). The double-pixelisation eliminates this but is not as yet supported by any software. Mark Calabretta ATNF _______________________________________________ fitsbits mailing list http://listmgr.cv.nrao.edu/mailman/listinfo/fitsbits |
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On Mon 2005/01/17 09:37:44 BST, Andreas Wicenec wrote in a message to: part of it is already useable. If there is interest I am willing to work it through and make it public. Hi Andreas, Thanks for the offer. It's a little early yet to say exactly what should be done software-wise, though I intend to restrict myself to the WCSLIB implementation of HPX. I'll let you know later when things become a bit clearer. Cheers, Mark |
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On Thu 2005/01/13 13:47:05 CDT, Wayne Landsman wrote in a message to: Eric Greisen wrote: AIPS cannot handle HEALPIX but can someone ? There is FORTRAN, C and IDL code for reading HEALPIX FITS files available by registering at http://www.eso.org/science/healpix/. There is also a IDL image display program MAPVIEW available from the WMAP software library (http://lambda.gsfc.nasa.gov/product/map/m_sw.cfm). Also, Roukema's isolat package http://cosmo.torun.pl/GPLdownload/do...-0.1.12.tar.gz is available (GPL) for converting between pixel number and position, finding the pixel closest to a given position, etc. Mark Calabretta ATNF |
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