nside2npix
This IDL facility provides the number of pixels Npix over the full sky corresponding
to resolution parameter Nside.
Location in HEALPix directory tree: src/idl/toolkit/nside2npix.pro
FORMAT
QUALIFIERS
-
Nside
- HEALPix resolution parameter (scalar integer),
should be a valid Nside (power of 2
)
-
Npix
- number of pixels, Npix = 12*Nside2 if Nside is a valid
resolution parameter or -1 otherwise
KEYWORDS
-
ERROR=
- error flag, set to 1 on output if Nside is NOT valid, or
stays to 0 otherwise.
DESCRIPTION
nside2npix checks that the given Nside is valid (power of 2 in
) and then computes the
corresponding number of pixels
.
RELATED ROUTINES
This section lists the routines related to nside2npix
-
idl
- version 6.4 or more is necessary to run nside2npix.
-
npix2nside
- computes Nside corresponding to Npix
-
pix2xxx, ang2xxx, vec2xxx, ...
- conversion between vector or angles and pixel index and vice-versa
-
vec2pix, pix2vec
- conversion between vector and pixel index
-
nest2ring, ring2nest
- conversion between NESTED and RING indices
EXAMPLE:
Npix will be 786432 the number of pixels over the full sky for the HEALPix
resolution parameter 256 and error will be 0
EXAMPLE:
Npix will be -1 and error: 1, because 248 is not a valid value for a HEALPix
resolution parameter
Version 3.30, 2015-10-08