inRing

Return list of pixels in a ring or ring section

Contents

Syntax

pixList = inRing(nSide, nRing, phi0, dPhi, 'Param1', Value1, ...);

Input Arguments

nSide       HEALPix resolution parameter
nRing       Ring number (1 <= nRing <= 4*nSide-1)
phi0, dPhi  (optional) Ring section longitudes [phi-dPhi,phi+dPhi]

Param       Value
'nest'      return pixels with nested indexing (true | {false})
'strict'    return only pixels whose center is in longitude range
            (true | {false})

Return Arguments

pixList     size(nRing) cell array of pixels in ring defined by nRing,
            phi0, dPhi

Description

nRing may be a numeric array, in which case phi0, dPhi and nest may each
be either scalar or a size(nRing) array. If strict is false (default)
then all pixels intersected by longitude range are included in pixList.

Example

% All pixels in ring 2 of nSide = 4 pixelization (ring indexed)
pix = inRing(4,2);
pix{:}

% Same, but nested indexing
pix = inRing(4,2,'nest',true);
pix{:}
nest2ring(4,pix{:})

% Pixels in rings [2,4;8,10;12,14] and the longitude band
% [7*pi/4,9*pi/4]
nRing = [2,3;5,12;13,14];
pix = inRing(4,nRing,2*pi,pi/4);
pix{1}
pix{end}

% Same, with strict selection
pix = inRing(4,nRing,2*pi,pi/4,'strict',true);
pix{1}
pix{end}

ans =

     5     6     7     8     9    10    11    12


ans =

    65    16    15    32    31    48    47    64


ans =

   137     1     5     2     7     3     9     4


ans =

    12     5     6


ans =

   188   181   182


ans =

    12     5


ans =

   188   181

See also

ringNum

Requires

ring2z, pix2vec

Copyright 2010-2011 Lee Samuel Finn. Terms of Use.

Published with MATLAB® 7.12