udgrade_nest*

Routine to degrade or prograde the pixel size of a HEALPix map indexed with the NESTED scheme. The degradation/progradation is done assuming an intensive quantity (like temperature) that does NOT scale with surface area.
In case of degradation, a big pixel that contains one or several bad pixels will take the average of the valid small pixels, unless a 'pessimistic' behavior is assumed in which case the big pixel will take the bad pixel sentinel value. In case of progradation, a bad pixel only spawns bad pixels.
The routine accepts both mono and bi-dimensional maps.

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

FORMAT

call udgrade_nest*( map_in, nside_in, map_out, nside_out[, fmissval, pessimistic] )

Arguments appearing in italic are optional.

ARGUMENTS

name & dimensionality	kind	in/out	description
map_in(0:12*nside_in**2-1)	SP/ DP	IN	mono-dimensional full sky map to be prograded or degraded.
map_in (0:12*nside_in**2-1,1:nd)	SP/ DP	IN	bi-dimensional full sky map to be prograded or degraded. The routine finds the second dimension (nd) by itself.
nside_in	I4B	IN	the $N_{\mathrm{side}}$ resolution parameter of the input map. Must be a power of 2.
map_out(0:12*nside_out**2-1)	SP/ DP	OUT	mono-dimensional full sky map after degradation or progradation.
map_out (0:12*nside_out**2-1,1:nd)	SP/ DP	OUT	bi-dimensional full sky map after degradation or progradation. The second dimension (nd) should match that of the input map.
nside_out	I4B	IN	the $N_{\mathrm{side}}$ resolution parameter of the output map. Must be a power of 2. If nside_out $>$ nside_in, the map is prograded (ie, more and smaller pixels) with each pixel having the same value as its parent; otherwise, the map in degraded (ie, fewer larger pixels), with each pixel being the average of its $($nside_in/nside_out$)^2$ components.
fmissval	SP/ DP	IN	sentinel value given to bad pixels in input and output maps.default:\tt HPX_SBADVAL or \tt HPX_DBADVAL
pessimistic	LGT	IN	if set to .true., during a degradation, a big pixel containing at least a small bad pixel will be returned as bad as well, instead of taking the average of the remaing valid pixels. default:.false.

EXAMPLE:

use udgrade_nr
call udgrade_nest(map_hi, 256, map_low, 64)

Degrades a NESTED ordered map with $N_{\mathrm{side}}=256$ into a NESTED map with $N_{\mathrm{side}}=64$

RELATED ROUTINES

This section lists the routines related to udgrade_nest*

udgrade_ring

prograde or degrade a RING ordered map.