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in_ring
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
FORMAT call in_ring(
nside, iz, phi0, dphi, listir, nir, nest
)
ARGUMENTS
| 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  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 |
OUT |
The pixel indexes in the slice. |
| nir |
I4B |
OUT |
the number of pixels in the slice. |
| nest (OPTIONAL) |
I4B |
IN |
The pixel indexes are in the NESTED numbering scheme if nest=1, and in RING scheme otherwise. |
EXAMPLE:
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  on the 10th ring.
MODULES & ROUTINESThis section lists the modules and routines used by in_ring.
-
ring2nest
- conversion from RING scheme pixel index to NESTED scheme pixel index
-
next_in_line_nest
- returns NESTED index of pixel lying to the East of the
current pixel and on the same ring
RELATED ROUTINESThis 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.
-
getdisc_ring
- find all pixels within a certain radius.
Eric Hivon
2010-06-18
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