The decoder GET_RASTER_DATA returns information on the radar site, volume scan time, radar operating mode, and on the radar data itself. The array IFIELD() contains values 0-15, which can be converted to physical units by using the elements in output vector ICATS().
The user may convert output values in IFIELD(,) to physical units through the relationship:
DBZ = ICATS(IFIELD(I,J)).
For velocity and spectrum width products, an IFIELD value of 0 indicates insufficient backscatterers within the volume to obtain a reliable estimate of the data there. Thus a 0 means indeterminate velocity (not a velocity of 0 m s-1). For other products a 0 indicates a value below the lowest threshold.
Note that all input and output variables are INTEGER*4 except:
IVAL(), IHEADER(), ITRAILER() : BYTE or CHARACTER*1
IFIELD(,) : BYTE
ICATT() : INTEGER*2
EXPLANATION OF CALLING SEQUENCE:
CALL GET_RASTER_DATA(IVAL,MSGLEN,ISITE,
1 ISITE_LAT,ISITE_LON,ISITE_ELEV,
2 IYR,IMONTH,IDAY,IHR,IMINIT,ISEC,
3 IPROD,MAXVAL,IVCP,IFIELD,NCOLS,NROWS,ICATT,ICATS,
4 NDIMS_P,IHEADER,LEN_HEADER,ITRAILER,LEN_TRAILER,ICODE)
IVAL( ) = BYTE OR CHARACTER*1 ARRAY CONTAINING GRAPHIC
MESSAGE, DIMENSIONED MSGLEN (INPUT)
MSGLEN = LENGTH OF GRAPHIC MESSAGE IN BYTES (INPUT)
ISITE = WSR-88D NUMERIC SITE ID (OUTPUT)
ISITE_LAT = SITE LATITUDE (DEG N), DEG X 1000 (OUTPUT)
ISITE_LON = SITE LONGITUDE (DEG E), DEG X 1000 (OUTPUT)
ISITE_ELEV = SITE ELEVATION, M MSL (OUTPUT)
IYR,IMONTH,IDAY
= PRODUCT DATE (OUTPUT)
IHR,IMINIT,ISEC
= PRODUCT TIME, UTC (OUTPUT)
IPROD = PRODUCT CODE NUMBER (OUTPUT) (EG 57 FOR VIL)
MAXVAL = MAXIMUM VALUE IN THE RASTER FIELD (OUTPUT)
IVCP = OPERATING VOLUME COVERAGE PATTERN (OUTPUT)
IFIELD(,) = RETURNED VALUES (DATA LEVELS 0-15) FOR THE FIELD
(OUTPUT); A BYTE VARIABLE DIMENSIONED
NCOLS,NROWS IN CALLING PROGRAM
IF ICATS() HAS BEEN DIMENSIONED 0:15, THEN VALUES
OF IFIELD(,) CAN BE CONVERTED TO PHYSICAL UNITS
BY THE RELATIONSHIP:
PHYSICAL VALUE = ICATS(IFIELD(I,J))
NCOLS,NROWS = DIMENSIONS OF IFIELD() (INPUT)
ICATT() = CATEGORY-INTERVAL VALUES AS TAKEN DIRECTLY
FROM PRODUCT HEADER (OUTPUT, INTEGER*2). MUST
BE DIMENSIONED BY 16 IN CALLING PROGRAM; FOR
CONSISTENCY WITH ILEVEL(,) VALUES IT IS ADVISABLE
TO USE THE DIMENSION 0:15.
ICATS() = CATEGORY-INTERVAL VALUES IN PHYSICAL UNITS
(OUTPUT). MUST BE DIMENSIONED BY 16 IN CALLING
PROGRAM; FOR CONSISTENCY WITH ILEVEL(,) VALUES
IT IS ADVISABLE TO USE THE DIMENSION 0:15.
NDIMS_P = ACTUAL NUMBER OF ROWS AND COLUMNS IN OUTPUT
PRODUCT (OUTPUT) (ROWS=COLUMNS IN 88D FILES)
IHEADER() = BYTE ARRAY WITH COPY OF HEADER. SHOULD BE
DIMENSIONED 160 IN CALLING ROUTINE (OUTPUT)
LEN_HEADER = ACTUAL NUMBER OF BYTES OF INFORMATION IN
IHEADER() (OUTPUT)
ITRAILER() = CHARACTER*1 ARRAY WITH TEXT INFORMATION
ATTACHED AT END OF FILE (IF ANY). SHOULD BE
DIMENSIONED BY 20 000 IN CALLING ROUTINE (OUTPUT)
LEN_TRAILER = ACTUAL NUMBER OF BYTES OF DATA IN ITRAILER().
WILL BE SET 0 IF NO TRAILER EXISTS (OUTPUT)
ICODE = OUTPUT RETURN CODE, CONDITIONS AS FOLLOWS:
0 : RETURN OK
2 : NOT A RECOGNIZED RASTER PRODUCT
3 : NCOLS/NROWS TOO SMALL FOR PRODUCT
4 : PRODUCT TOO LARGE FOR MSGLEN
Interface Control Document for Product Specification (Document Number 2620003A, WSR-88D OSF, June 26, 1998)
Interface Control Document for the RPG Associated PUP ( Document Number 2620001A, WSR-88D OSF, June 26, 1998) WSR-88D Digital Precipitation Array Product Decoder
| Version | Date | Summary of Changes |
|---|---|---|
| 1.0 | 03/01/2000 | Initial Version |
The latest version of the WSR-88D raster graphic product decoder can be downloaded and utilized free of charge, subject to the usual NWS disclaimer, click here to download a copy.
