nest2uniq

This IDL facility turns N_side and (NESTED) pixel index into the Unique Identifier .

Location in HEALPix directory tree: src/idl/toolkit/nest2uniq.pro 

FORMAT

IDL> nest2uniq, Nside, Pnest, Puniq [,/HELP]

QUALIFIERS

Nside

(IN, scalar or vector Integer) The HEALPix N_side parameter(s)

Pnest

(IN, scalar or vector Integer) (NESTED scheme) pixel identification number(s) in the range {0, 12N_side²-1}. If Nside is a scalar, Pnest can a be a scalar or a vector, if Nside is a vector, Pnest must be a vector of the same size

Puniq

(OUT, same size as Pnest) The HEALPix Unique pixel identifier(s).

KEYWORDS

/HELP

If set, a documentation header is printed out, and the routine exits

DESCRIPTION

nest2uniq turns the parameter N_side (a power of 2) and the pixel index p into the Unique ID number u = p + 4 N_side². See ”The Unique Identifier scheme” section in ”HEALPix Introduction Document” for more details.

EXAMPLE:

nest2uniq, [1, 2, 4], [0, 0, 0], puniq
print, puniq

returns
4 16 64
since the first pixels (p=0) at N_side= 1, 2 and 4 are respectively the pixels with Unique ID numbers 4, 16 and 64.

RELATED ROUTINES

This section lists the routines related to nest2uniq

uniq2nest

Transforms Unique HEALPix pixel ID number into Nside and Nested pixel number

pix2xxx,...

to turn NESTED pixel index into sky coordinates and back