GEO_del_limit_check.c

Go to the documentation of this file.

/* file: GEO_del_limit_check.c */
 
#include "PGS_MODIS_35251.h"
#include "smfio.h"
#include "GEO_validation.h"
 
int GEO_del_limit_check(
    double data_samples[],
    int const number_of_samples,
    double const delta_limit,
    int sample_flags[]
    )
/*
!C****************************************************************************
 
!Description:   
    Routine in Input group of the Level-1A geolocation software to validate
    a set of data samples by comparing differences between successive
    samples against a limit.  Previously flagged values are not checked.
    Flags set to BAD_DATA for all samples not within limits.             
 
!Input Parameters:
    data_samples        array of input data samples
    number_of_samples   number of samples to check
    delta_limit     difference limit
 
!Output Parameters:
 
!Input/Output Parameters:
    sample_flags        array of validation flags with previously
                invalidated samples flagged 
 
Return Values:
    SUCCESS - if it can find at least one valid pair of values.
    FAIL    - otherwise
 
Externally Defined:
    BAD_DATA        "GEO_validation.h"
    FAIL            "GEO_basic.h"
    MODIS_E_BAD_INPUT_ARG   "PGS_MODIS_35251.h"
    MODIS_E_ONE_UNFLAG  "PGS_MODIS_35251.h"
    SUCCESS         "GEO_basic.h"
 
Called by:
    GEO_prepare_mirr_data
    GEO_validate_attit_data
 
Routines Called:
    GEO_find_next_flag
    modsmf
 
!Revision History:
$Log: GEO_del_limit_check.c,v $
Revision 4.2  2003/08/28 16:01:45  kuyper
Corrected prolog.
 
Revision 4.1  2003/02/21 22:53:21  kuyper
Corrected to use void* pointers with %p format code.
 
Revision 3.2  2001/03/16 20:55:05  kuyper
Changed to not return FAIL for number_of_samples = 0
 
Revision 3.1  2001/03/07  19:33:25  kuyper
Major rewrite, to mark both sides of a sudden jump as bad.
 
James.R.Kuyper.1@gsfc.nasa.gov
 
Requirements:
    PR03-F-2.4-1
    PR03-F-2.4-2
    PR03-F-2.5-1
    PR03-F-2.5-2
    PR03-F-2.5-3
    PR03-I-1
    PR03-I-2
    PR03-S-1
 
!Team-unique Header:
    This software is developed by the MODIS Science Data Support
    Team for the National Aeronautics and Space Administration,
    Goddard Space Flight Center, under contract NAS5-32373.
 
References and Credits
 
Design Notes
 
!END*************************************************************************
 */
{
 
    /* Local variable declarations */
 
    double del = 0.0; /* absolute value of difference */
    double limit = 0.0; /* limit value */
    int num_valid = 0; /* number of valid data samples found */
    int f1 = -1; /* array index */
    int f2 = -1; /* array index */
    char msgbuf[64];
 
    if(data_samples==NULL || sample_flags==NULL)
    {
    sprintf(msgbuf, "data_samples:%p sample_flags:%p",
        (void*)data_samples, (void*)sample_flags);
    modsmf(MODIS_E_BAD_INPUT_ARG, msgbuf, __FILE__ ", GEO_del_limit_check");
 
    return FAIL;
    }
    /* Begin program logic */
    while( (f2=GEO_find_next_flag(sample_flags,number_of_samples,f2+1))>=0)
    {
    if(f1 < 0) /* First time    */
        num_valid++;
    else
    {
        del = fabs(data_samples[f2] - data_samples[f1]);
        limit = delta_limit * (double)(f2 - f1);
        if (del > limit) {
        if(sample_flags[f1] != BAD_DATA)
        {
            num_valid--;    /* We counted it as valid earlier.*/
            sample_flags[f1] = BAD_DATA;
        }
 
        sample_flags[f2] = BAD_DATA;
        }
        else
          num_valid++;
    }
 
    f1 = f2;
    }
 
    if (num_valid ==0 && number_of_samples > 0)
    return FAIL;
      
    if (num_valid == 1)
    modsmf(MODIS_E_ONE_UNFLAG, "", __FILE__ ", GEO_del_limit_check");
 
    return SUCCESS;
}