udgrade_ring*


Routine to degrade or prograde the pixel size of a HEALPix map indexed with the RING 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_ring*( 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 INOUT mono-dimensional full sky map to be prograded or degraded. The routine finds the second dimension (nd) by itself. Note that the map is modified on output (reordered into NESTED scheme).
map_in (0:12*nside_in**2-1,1:nd) SP/ DP INOUT bi-dimensional full sky map to be prograded or degraded. Note that the map is modified on output (reordered into NESTED scheme).
nside_in I4B IN the ${N_{\rm side}}$ 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 ${N_{\rm side}}$ 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_ring(map_hi, 256, map_low, 64)
Degrades a RING ordered map with ${N_{\rm side}}=256$ into a RING map with ${N_{\rm side}}=64$


RELATED ROUTINES

This section lists the routines related to udgrade_ring*

udgrade_nest
prograde or degrade a NESTED ordered map.

Version 3.31, 2017-01-06