UDF PROGRAMMERS MANUAL





 convert_to_units (1) 
     UDF PROGRAMMERS MANUAL
     convert_to_units (1)
 


  NAME   convert_to_units




 SYNOPSIS  



 #include "libbase_udf.h"


 ByTe_2
     convert_to_units
     (u_ByTe_4 Key, ByTe_1 *Ext, 
                       u_ByTe_2 Ver, void *UDF, 
                       ByTe_1 DataField, ByTe_1 AncOrMode, 
                       ByTe_1 NAS, ByTe_1 *Tbls, 
                       ByTe_2 *Ops, ReaL_4 RetData, 
                       ByTe_1 ChkForFill, ByTe_4 Fill);







 INPUT DEFINITIONS 







 Key
     -
     UDF data key


 Ext 
     -
     UDF file extension


 Ver 
     -
     Version number


 UDF 
     -
     General data structure


 DataField 
     -
     Type of data to be converted


 



 SENSOR


 DSENSOR


 SCAN_INDEX


 DSCAN_INDEX


 ANCILLARY


 DANCILLARY


 MODE


 DMODE


 D_QUAL


 PITCH_ANGLE


 START_AZ_ANGLE


 STOP_AZ_ANGLE





 AncOrMode 
     -
     Ancillary data set number or status byte number 


 NAS 
     -
     Number of algorithm steps in conversion


 Tbls 
     -
     VIDF tables to use in each algorithm step


 Ops 
     -
     Operations to perform at each algorithm step


 RetData 
     -
     Converted data


 ChkFill 
     -
     Remove fill data flag


 



 0
     -
     No check is made for fill data 


 1
     -
     Check for fill data





 Fill 
     -
     The fill value to check for







  DESCRIPTION  
 convert_to_units() takes the raw UDF DataField 
obtained in the last read_drec()
call with UDF to floating point data.  If converting either 
MODE or ANCILLARY data then the VIDF mode number or the VIDF 
ancillary data set number must be supplied in AncOrMode.




In the conversion process the raw UDF data is passed through a 
transformation algorithm which may do as little as just return the 
raw input data or may convert the data into physical units.  The 
conversion algorithm consists of a number of algorithm steps 
(NAS), each step consisting of the an operation (Ops) 
applied possibly in conjuntion with information contained in one 
of the VIDF tables (Tbls).  When no table is used with a 
given algorithm step it's value in the Tbls array should be set 
to 0.  To simply pass the raw UDF data back set NAS to 0.




The converted UDF data is returned to the calling environment in
RetData.  The user is responsible for ensuring that 
RetData is large enough to handle all of the returned data.
RetData will be double precision if Datafield is
set to DSENSOR, DSCAN_INDEX, DANCILLARY, or 
DMODE.  It is single precision in all other options.
When returning double precision data, the pointer to the return
array is cast to a single precision pointer (ReaL_4 *) on input.




If ChkFill is set then prior to conversion the raw UDF data 
will be checked against Fill.  Raw data found matching this
value will be set to OUTSIDE_MIN.




Under normal conditions Ext should be set to a NULL string.  
Setting Ext to a non-NULL string will cause the file_pos
routine to attempt to use the appropriate named UDF header and data
files but with the string .Ext appended to it.  The file must 
exist in the current working directory.  




  RETURN VALUE  
  On success, ALL_OKAY is returned, otherwise an error code is
returned.




  ERRORS  
 CNVT_NOT_FILLED  No opened file (file_open not called?) 
 CNVT_BAD_DTYPE   Unknown DataField value
 CNVT_BAD_TBL_NUM  Table number larger than number of tables
 CNVT_TMP_MALLOC  Malloc error in setting up tmp space




  APPLICABLE FORMATS  
  UDF V2.2, IDFS V2.1




  RESTRICTIONS  
 None




  SEE ALSO  
ret_codes(1H)
user_defs(1)
read_drec (1)









 UDF V2.2 July 31, 1999
     UDF V2.2
 










  

    
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