HEALPix Publisher's description
Software for pixelization, hierarchical indexation, synthesis, analysis, and visualization of data on the sphere
HEALPix is an acronym for Hierarchical Equal Area isoLatitude Pixelization of a sphere. As suggested in the name, this pixelization produces a subdivision of a spherical surface in which each pixel covers the same surface area as every other pixel. The figure below shows the partitioning of a sphere at progressively higher resolutions, from left to right. The green sphere represents the lowest resolution possible with the HEALPix base partitioning of the sphere surface into 12 equal sized pixels. The yellow sphere has a HEALPix grid of 48 pixels, the red sphere has 192 pixels, and the blue sphere has a grid of 768 pixels (~7.3 degree resolution).
Another property of the HEALPix grid is that the pixel centers, represented by the black dots, occur on a discrete number of rings of constant latitude, the number of constant-latitude rings is dependent on the resolution of the HEALPix grid. For the green, yellow, red, and blue spheres shown, there are 3, 7, 15, and 31 constant-latitude rings, respectively.
Two high-resolution examples of applications of HEALPix are shown below. The first example (left) is an Earth topography map composed of 3,145,728 pixels (~7 arcmin resolution) and the second (right) is a model of the Cosmic Microwave Background (CMB) radiation temperature anisotropy, composed of 12,582,912 pixels (~3.4 arcmin resolution).
What's New in This Release:C++
* Faster Spherical Harmonic Transforms thanks to libpsht routines
* Support for spin-weighted Spherical Harmonic Transforms at the library level
* Support for 6-component power spectra in anafast_cxx
* The smoothing_cxx module allows ``unsmoothing'' a map by specifying a negative FWHM value
* Module median_filter renamed to median_filter_cxx to avoid name clashes with Fortran
* bug fix in the nested ang2pix functions (provided by Craig J Copi)
* FITS I/O performance improvements
* Faster Spherical Harmonics Transforms thanks to libpsht routines
* Nside > 8192 now supported by most routines and facilities * Slightly faster pixel/coordinates conversion routines (eg ang2pix_*, vec2pix_*, ...)
* improved map2gif facility
* fits2cl: addition of the WMAP1 and WMAP5 keywords to read best fit C(l) model to WMAP 1st and 5yr data respectively,
* cartview, gnomview, mollview, orthview: larger choice of supported symbols in OUTLINE option.
* bugs correction in query_disc
System Requirements:No special requirements.
Program Release Status: Minor Update
Program Install Support: Install and Uninstall