For a input binary mask in NESTED ordering, size_holes_nest identifies the pixels located on the inner boundary of invalid regions

Location in HEALPix directory tree: src/f90/mod/mask_tools.F90 


call size_holes_nest( nside, mask, nholes, nph, [tags, sizeholes, listpix] )

Arguments appearing in italic are optional.


name & dim. kind in/out description
nside I4B IN The Nside value of the input mask.
mask(0:Npix-1) I4B IN Input binary NESTED-ordered mask. Npix = 12*nside*nside
nholes I4B OUT Number of holes found
nph I4B OUT Number of pixels in holes
tags(0:Npix-1) (OPTIONAL) I4B OUT Pointer allocated by size_holes_nest, containing a sky map in which invalid pixels belonging to the largest hole have value -1, those belonging to the second largest hole have value -2, and so on, while valid pixels keep value +1.
sizeholes(0:nholes-1) I4B OUT Pointer allocated by size_holes_nest, containing on output the respective size of each hole (in decreasing order). Eg, sizeholes(0) is the number of pixels in the largest hole (taking value -1 in tags).
listpix(0:nholes+nph) I4B OUT Pointer allocated by size_holes_nest, containing on output the indexed list of pixels in each hole. Pixels located in the first (and largest) hole are given by listpix(listpix(0):listpix(1)-1)


use healpix_types
use healpix_modules
call size_holes_nest(nside, mask, nholes, nph)


This section lists the modules and routines used by size_holes_nest.

mask processing module (see related routines below)


This section lists the routines related to size_holes_nest

angular distance to closest invalid pixel of the given mask
turn to valid all pixels located in 'holes' containing fewer pixels than the given threshold
identify inner boundary pixels of 'holes' for given mask
returns size (in pixels) of holes found in input mask

Version 3.31, 2017-01-06