1 / 7

Healpix for Science Tools

Healpix for Science Tools. Toby Burnett, Bruce Lesnick University of Washington. The Healpix class: an STL containers of Pixels. Constructor: set up nside (number of pixels) mode (nested or ring) and coord system begin() and end() methods: return iterator that evaluate to pixels.

jalila
Download Presentation

Healpix for Science Tools

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Healpix for Science Tools Toby Burnett, Bruce Lesnick University of Washington Science Tools Meeting 1/24/05 - T. Burnett

  2. The Healpix class: an STL containers of Pixels • Constructor: set up nside (number of pixels)mode (nested or ring) and coord system • begin() and end() methods: return iterator that evaluate to pixels. • Following code uses STL methods to create an image MapParameters par(argc, argv);// defines image parameters SkyImage piximage(par); // manage a FITS image Healpix hpix(8); // create a Healpix object, nside=8 std::for_each( h.begin(), h.end(), DrawPixel(hix,piximage)); Science Tools Meeting 1/24/05 - T. Burnett

  3. HTM pixel directions Level=3512 pixels Science Tools Meeting 1/24/05 - T. Burnett

  4. HEALPix pixel directions nside=8, 778 pixels Science Tools Meeting 1/24/05 - T. Burnett

  5. The Pixel class: nested in Healpix Behave like • The constructor Healpix::Pixel(const astro::SkyDir& dir, const Healpix &hp)creates a pixel containing the SkyDir direction dir, for the Healpix object hp. • The methodHealpix::Pixel::operator astro::SkyDir ()constreturns the pixel central direction as a SkyDir: a Pixel “behaves” like a SkyDir. • A pixel “knows” its • direction • Area (solid angle) • Neighboring pixels (7 or 8) construct Science Tools Meeting 1/24/05 - T. Burnett

  6. Image based on Healpix: class HealpixData • Simple wrapper of an array of pixel values and a Healpix object. • Inherit from SkyImage, and that is it! Display data from WMAP Science Tools Meeting 1/24/05 - T. Burnett

  7. Status • HTM and Healpix created to do integrals over the sphere. • Also a good way to pixelate exposure functions, and bin the data for sky survey • Class Healpix: • Using C code from WMAP • Code to obtain neighbors converted from Fortran. • Class HealpixData: Science Tools Meeting 1/24/05 - T. Burnett

More Related