NASA Ocean Color

ocssw V2022
 #include "l12_proto.h"
 /*
  *  viirs_pxcvt.c contains routines for conversion of unaggregated to 
  *  aggregated VIIRS pixels and visa versa.  Also, it finds an 
  *  aggregated pixel that is x unaggregated samples away.
  */
 static int ag_px_st[] = {0, 640, 1008, 2192, 2560, 3200};
 static int ag_fact[] = {1, 2, 3, 2, 1, -1};
 static int uag_px_st[] = {0, 640, 1376, 4928, 5664, 6304};
  
 void viirs_pxcvt_2uag(int in_pix, int *out_pix, int *nag)
 /*******************************************************************
  
    viirs_pxcvt_2uag
  
    purpose: convert pixel number from aggregated to unaggregated
  
    Returns type: void
  
    Parameters: (in calling order)
       Type              Name            I/O     Description
       ----              ----            ---     -----------
       int               in_pix           I      aggregated pixel number
       int *             out_pix          O      unaggregated pixel number
       int *             nag              O      number of samples aggregated
                                                 at this agregated pixel
  
    Modification history:
       Programmer        Date            Description of change
       ----------        ----            ---------------------
       W. Robinson       15-Aug-2011     Original development
  
   Note that the mapping from aggregated to unaggregated makes a range of 
   pixel numbers from out_pix -> out_pix + nag - 1
  
  *******************************************************************/ {
     int found, nzone = 6, iz;
     /*
      *  Find the zone for the pixel and convert it to the unaggregated value
      */
     found = 0;
     for (iz = 0; iz < (nzone - 1); iz++) {
         if ((in_pix >= ag_px_st[iz]) && (in_pix < ag_px_st[ iz + 1 ])) {
             *out_pix = uag_px_st[iz] + (in_pix - ag_px_st[iz]) * ag_fact[iz];
             *nag = ag_fact[iz];
             found = 1;
             break;
         }
     }
     /*
      *  extrapolate for values outside actual range
      */
     if (found != 1) {
         *nag = 1;
         if (in_pix < ag_px_st[0])
             *out_pix = in_pix;
         else
             *out_pix = uag_px_st[ nzone - 1 ] + in_pix - ag_px_st[ nzone - 1 ];
     }
 }
  
 void viirs_pxcvt_2ag(int in_pix, int *out_pix)
 /*******************************************************************
  
    viirs_pxcvt_2ag
  
    purpose: convert pixel number from unaggregated to aggregated
  
    Returns type: void
  
    Parameters: (in calling order)
       Type              Name            I/O     Description
       ----              ----            ---     -----------
       int               in_pix           I      unaggregated pixel number
       int *             out_pix          O      aggregated pixel number
  
    Modification history:
       Programmer        Date            Description of change
       ----------        ----            ---------------------
       W. Robinson       15-Aug-2011     Original development
  
  *******************************************************************/ {
     int found, nzone = 6, iz;
     /*
      *  Find the zone for the pixel and convert it to the aggregated value
      */
     found = 0;
     for (iz = 0; iz < (nzone - 1); iz++) {
         if ((in_pix >= uag_px_st[iz]) && (in_pix < uag_px_st[ iz + 1 ])) {
             *out_pix = ag_px_st[iz] + (in_pix - uag_px_st[iz]) / ag_fact[iz];
             found = 1;
             break;
         }
     }
     /*
      *  extrapolate for values outside actual range
      */
     if (found != 1) {
         if (in_pix < uag_px_st[0])
             *out_pix = in_pix;
         else
             *out_pix = ag_px_st[ nzone - 1 ] + in_pix - uag_px_st[ nzone - 1 ];
     }
 }
  
 void viirs_pxcvt_agdel(int in_pix, int del, int *out_pix)
 /*******************************************************************
   
    viirs_pxcvt_agdel
  
    purpose: add unaggregated samples to aggregated pixel numbers
  
    Returns type: void
  
    Parameters: (in calling order)
       Type              Name            I/O     Description
       ----              ----            ---     -----------
       int               in_pix           I      aggregated pixel number
       int               del              I      unaggregated sample offset
       int *             out_pix          O      final aggregated pixel number
  
    Modification history:
       Programmer        Date            Description of change
       ----------        ----            ---------------------
       W. Robinson       15-Aug-2011     Original development
  
  *******************************************************************/ {
     int uag_px, ag;
     /*
      *  get the unaggregated pixel
      */
     viirs_pxcvt_2uag(in_pix, &uag_px, &ag);
     /*
      *  add the offset, if in (+) direction, make sure it is from highest 
      *  unaggregated pixel # possible
      */
     uag_px = (del < 0) ? uag_px + del : uag_px + (ag - 1) + del;
     /*
      *  convert back to aggregated and done
      */
     viirs_pxcvt_2ag(uag_px, out_pix);
 }
viirs_pxcvt_2ag
void viirs_pxcvt_2ag(int in_pix, int *out_pix)
Definition: viirs_pxcvt.c:62
l12_proto.h
viirs_pxcvt_agdel
void viirs_pxcvt_agdel(int in_pix, int del, int *out_pix)
Definition: viirs_pxcvt.c:106
viirs_pxcvt_2uag
void viirs_pxcvt_2uag(int in_pix, int *out_pix, int *nag)
Definition: viirs_pxcvt.c:11