Routine to find the pixel index of all pixels on a slice of a given ring. The output indices can be either in the RING or NESTED scheme, depending on the nest keyword.

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


call in_ring( nside, iz, phi0, dphi, listir, nir, nest )


name & dimensionality kind in/out description
nside I4B IN the Nside parameter of the map.
iz I4B IN ring number, counted southwards from the north pole.
phi0 DP IN central $\phi$ position in the slice.
dphi DP IN defines the size of the slice. The slice has length 2 x dphi along the ring with center at phi0.
listir(0:4*nside-1) I4B/ I8B OUT The pixel indexes in the slice.
nir I4B OUT the number of pixels in the slice. nir $\le 4{N_{\rm side}}$
nest (OPTIONAL) I4B IN The pixel indexes are in the NESTED numbering scheme if nest=1, and in RING scheme otherwise.


call in_ring(256, 10, 0, 0.1, listir, nir, nest=1)
Returns the NESTED pixel index of all pixels within 0.1 radians on each side of $\phi=0$ on the 10th ring.


This section lists the modules and routines used by in_ring.

conversion from RING scheme pixel index to NESTED scheme pixel index
returns NESTED index of pixel lying to the East of the current pixel and on the same ring


This section lists the routines related to in_ring

pix2ang, ang2pix
convert between angle and pixel number.
pix2vec, vec2pix
convert between a cartesian vector and pixel number.
find all pixels within a certain radius.

Version 3.31, 2017-01-06