NASA Ocean Color

ocssw V2022

 #include "L1A_prototype.h"
 #include "hdf.h"
 #include "PGS_IO_L0.h"
 #include "EN_eng_data.h"
 #include "PH_pkt_hdr.h"
 #include "PD_pkt_data.h"
  
 void   update_eng_data (uint16             index,
                         PGSt_IO_L0_Packet  *eng_packet,
                         uint16             scan_number,
                         EN_VDATA_TYPE_t    *eng_data, 
                         int                use_cp_prior_offset)
  
 /*
 !C*****************************************************************************
  
 !Description:  This function updates the Vdata referenced by 'index' in
                the eng_data (array) structure with field values extracted
                from the eng_packet, and updates the Vdata's LAST_VALID_SCAN
                field with the scan_number. If use_cp_prior_offset is True
                then the bit offset EN_CP_HK_TLMY_PRIOR_OFFSET will be added
                to the start bit positions of the Vdata fields.
  
 !Input Parameters:
                uint16              index        ** The eng_data (array) index 
                                    of the eng Vdata to 
                                    update **
                PGSt_IO_LO_Packet  *eng_packet   ** The eng packet from which 
                                    to extract values to update
                                    the eng data with **
                uint16              scan_number  ** The scan number (counting 
                                    from 1) of the current scan
                                    within the current 
                                    granule **
  
                boolean             use_cp_prior_offset  ** whether or not to use
                                                       the bit offset: 
                                                       EN_CP_HK_TLMY_PRIOR_OFFSET
                                                       (should only be set to True
                                                       when updating eng_data for 
                                                       the "prior" part of eng pkt
                                                       2-1 **
  
 !Output Parameters:
                None
  
 !Input/Output Parameters:
                EN_VDATA_TYPE_t     *eng_data    ** The Vdata array structure **
  
 Return Values: 
                None
  
 Externally Defined:
                EN_VDATA_START_INDEX         (EN_eng_data.h)
                EN_CP_HK_TLMY_PRIOR_OFFSET   (EN_eng_data.h)
                EN_VDATA_TYPE_t              (EN_eng_data.h)
                PGSt_IO_LO_Packet            (PGS_IO.h)
                PD_NUM_BITS_IN_BYTE          (PD_pkt_data.h)
                PD_PKT_CONTENTS_BYTE_OFFSET  (PD_pkt_data.h)
  
 Called By:
                process_cp_hk_tlmy
                process_sci_eng_data
                update_eng_data_for_maj_cycle_n
  
 Routines Called:
                extr_bits
  
 !Revision History:
                revision 1.0 1997/09/12  17:30:00
                Qi Huang/RDC    (qhuang@ltpmail.gsfc.nasa.gov)
                Original development
  
 !Team-unique Header:
                This software is developed by the MODIS Science
                Data Support Team (SDST) for the National Aeronautics
                and Space Administration (NASA), Goddard Space Flight
                Center (GSFC), under contract NAS5-32373.
  
 !References and Credits:
                None
  
 !Design Notes:    
                (c.f. CDRL Table 30-5D and the Vdata_list file)
  
 !END************************************************************************
 */
 {
   /******************************************************************************/
   /*                                                                            */
   /*               Define and Initialize Local Variables                        */
   /*                                                                            */
   /******************************************************************************/
  
   int                  bit_offset;
   int                  num_fields_this_vdata;
   int                  start_pos;
   int                  num_bits;
   int                  start_byte;
   int                  start_bit;
   int                  i;
  
  
   /******************************************************************************/
   /*                                                                            */
   /*   The sci eng Vdatas' start bit positions are relative to the start of the */
   /*   packet header, while those of the cp hk telemetry Vdatas' are relative   */
   /*   to the start of the packet's data field... so if the vdata to update is  */
   /*   one of the former (as shown by the index being >= ENG_VDATA_START_INDEX),*/
   /*   then subtract the number of header bits (144) to get the packet data     */
   /*   start bit position.                                                      */
   /*                                                                            */
   /*        -----------------------------------------------------------------   */
   /*                                                                            */
   /*  IF ( index < EN_ENG_VDATA_START_INDEX ) THEN                              */
   /*    set bit_offset to 0                                                     */
   /*  ELSE                                                                      */
   /*    set bit_offset to -144                                                  */
   /*  ENDIF                                                                     */
   /*                                                                            */
   /******************************************************************************/
  
   if (index < EN_ENG_VDATA_START_INDEX)
     bit_offset = 0;
   else
     bit_offset = -144;
  
  
   /******************************************************************************/
   /*                                                                            */
   /*     if use_cp_prior_offset is True then add EN_CP_HK_TLMY_PRIOR_OFFSET to  */
   /*     the bit_offset                                                         */
   /*                                                                            */
   /*        -----------------------------------------------------------------   */
   /*                                                                            */
   /*  IF ( use_cp_prior_offset )                                                */
   /*  THEN                                                                      */
   /*    increment bit_offset by EN_CP_HK_TLMY_PRIOR_OFFSET                      */
   /*  ENDIF                                                                     */
   /*                                                                            */
   /******************************************************************************/
  
   if (use_cp_prior_offset)
     bit_offset += EN_CP_HK_TLMY_PRIOR_OFFSET;
  
  
   /******************************************************************************/
   /*                                                                            */
   /*     set the LAST_VALID_SCAN field (the first field in                      */
   /*     every Vdata) to scan_number                                            */
   /*                                                                            */
   /*        -----------------------------------------------------------------   */
   /*                                                                            */
   /*  set eng_data[index].field[0] to scan_number                               */
   /*                                                                            */
   /*  set num_fields_this_vdata to eng_data[index].num_fields                   */
   /*                                                                            */
   /******************************************************************************/
  
   eng_data[index].field[0].value = scan_number;
   num_fields_this_vdata = eng_data[index].num_fields;
  
  
   /******************************************************************************/
   /*                                                                            */
   /*  DO FOR ( i = 1 to (num_fields_this_vdata - 1) )                           */
   /*                                                                            */
   /*    set start_pos to (eng_data[index].field[i].start_bit_pos + bit_offset)  */
   /*                                                                            */
   /*    set num_bits to eng_data[index].field[i].num_bits                       */
   /*                                                                            */
   /*    calculate start_byte and start_bit from start_pos                       */
   /*                                                                            */
   /*    CALL extr_bits to get the bits from the packet                          */
   /*      INPUTS:  eng_packet, start_byte, start_bit, num_bits                  */
   /*      OUTPUTS: None                                                         */
   /*      RETURN:  value                                                        */
   /*    set eng_data[index].field[i].value to the returned value                */
   /*                                                                            */
   /*  END DO                                                                    */
   /*                                                                            */
   /******************************************************************************/
  
   for (i=1; i<num_fields_this_vdata; i++)
     {
       start_pos = eng_data[index].field[i].start_bit_pos + bit_offset;
       num_bits = eng_data[index].field[i].num_bits;
       start_byte = (start_pos / PD_NUM_BITS_IN_BYTE) + PD_PKT_CONTENTS_BYTE_OFFSET;
       start_bit = start_pos % PD_NUM_BITS_IN_BYTE;
       eng_data[index].field[i].value = extr_bits(eng_packet,start_bit,start_byte,
                                                  num_bits);
     }
  
   return;
 }

index

an array had not been initialized Several spelling and grammar corrections were which is read from the appropriate MCF the above metadata values were hard coded A problem calculating the average background DN for SWIR bands when the moon is in the space view port was corrected The new algorithm used to calculate the average background DN for all reflective bands when the moon is in the space view port is now the same as the algorithm employed by the thermal bands For non SWIR changes in the averages are typically less than Also for non SWIR the black body DNs remain a backup in case the SV DNs are not available For SWIR the changes in computed averages were larger because the old which used the black body suffered from contamination by the micron leak As a consequence of the if SV DNs are not available for the SWIR the EV pixels will not be the granule time is used to identify the appropriate tables within the set given for one LUT the first two or last two tables respectively will be used for the interpolation If there is only one LUT in the set of it will be treated as a constant LUT The manner in which Earth View data is checked for saturation was changed Previously the raw Earth View DNs and Space View DNs were checked against the lookup table values contained in the table dn_sat The change made is to check the raw Earth and Space View DNs to be sure they are less than the maximum saturation value and to check the Space View subtracted Earth View dns against a set of values contained in the new lookup table dn_sat_ev The metadata configuration and ASSOCIATEDINSTRUMENTSHORTNAME from the MOD02HKM product The same metatdata with extensions and were removed from the MOD021KM and MOD02OBC products ASSOCIATEDSENSORSHORTNAME was set to MODIS in all products These changes are reflected in new File Specification which users may consult for exact the pow functions were eliminated in Emissive_Cal and Emissive bands replaced by more efficient code Other calculations throughout the code were also made more efficient Aside from a few round off there was no difference to the product The CPU time decreased by about for a day case and for a night case A minor bug in calculating the uncertainty index for emissive bands was corrected The frame index(0-based) was previously being used the frame number(1-based) should have been used. There were only a few minor changes to the uncertainty index(maximum of 1 digit). 3. Some inefficient arrays(Sigma_RVS_norm_sq) were eliminated and some code lines in Preprocess_L1A_Data were moved into Process_OBCEng_Emiss. There were no changes to the product. Required RAM was reduced by 20 MB. Now

EN_VDATA_TYPE_t::num_fields

uint8 num_fields

Definition: EN_eng_data.h:124

EN_ENG_VDATA_START_INDEX

#define EN_ENG_VDATA_START_INDEX

Definition: EN_eng_data.h:65

EN_VDATA_TYPE_t::field

EN_FIELD_TYPE_t field[EN_MAX_FIELDS_PER_VDATA]

Definition: EN_eng_data.h:125

update_eng_data

void update_eng_data(uint16 index, PGSt_IO_L0_Packet *eng_packet, uint16 scan_number, EN_VDATA_TYPE_t *eng_data, int use_cp_prior_offset)

Definition: update_eng_data.c:8