W3FT07

The W3FT07 routine transforms data contained in a given
           grid array by translation, rotation about a common
           point and dilatation in order to create a new grid 
           array according to specifications.

USAGE:    CALL W3FT07(FLDA,IA,JA,AIPOLE,AJPOLE,BIPOLE,BJPOLE,DSCALE,
                      ANGLE,LINEAR,LDEFQQ,DEFALT,FLDB,IB,JB)

   Input argument list:
      FLDA(IA,JA)   - REAL*4 ORIGINAL SOURCE GRID-POINT DATA FIELD
      AIPOLE,AJPOLE - REAL*4 COMMON POINT I- AND J-COORDINATES OF THE
                      ORIGINAL FIELD, ASSUMING A RIGHT-HAND CARTESIAN
                      COORDINATE SYSTEM. THE POINT NEED NOT BE INSIDE
                      THE BOUNDS OF EITHER GRID
                      AND CAN HAVE FRACTIONAL VALUES.
                      COMMON POINT ABOUT WHICH TO ROTATE THE GRIDPOINTS
      BIPOLE,BJPOLE - REAL*4 COMMON POINT I- AND J-COORDINATES FOR
                      TRANSFORMED DESTINATION GRID
      DSCALE - REAL*4 SCALE-CHANGE (DILATION) EXPRESSED AS
                      A RATIO OF THE TRANSFORMED FIELD TO THE ORIGINAL
                      FIELD
                      DSCALE = GRDLENKM(DESTINATION) / GRDLENKM(SOURCE)
 
      ANGLE  - REAL*4 DEGREE MEASURE OF THE ANGLE REQUIRED TO
                      ROTATE THE J-ROW OF THE ORIGINAL GRID INTO
                      COINCIDENCE WITH THE NEW GRID. (+ COUNTER-
                      CLOCKWISE, - CLOCKWISE)
                      ANGLE = VERTLONW(SOURCE) - VERTLONW(DESTINATION)
 
      LINEAR - LOGICAL*4 INTERPOLATION-METHOD SELECTION SWITCH:
                       .TRUE.   BI-LINEAR INTERPOLATION
                       .FALSE.  BI-QUADRATIC INTERPOLATION
 
      LDEFQQ - LOGICAL*4 DEFAULT-VALUE SWITCH:
                       IF .TRUE. THEN
                         USE DEFAULT-VALUE FOR DESTINATION POINT
                         OUT-OF-BOUNDS OF GIVEN GRID;
                       ELSE
                         EXTRAPOLATE COARSELY FROM NEARBY BNDRY POINT
 
      DEFALT - REAL*4  THE DEFAULT-VALUE TO USE IF LDEFQQ = .TRUE.
 
   Output argument list:
      FLDB(IB,JB) - REAL*4 RESULTING TRANSFORMED DESTINATION FIELD
 
REMARKS:
        LIST CAVEATS, OTHER HELPFUL HINTS OR INFORMATION
        IN GENERAL 'FLDA' AND 'FLDB' CANNOT BE EQUIVALENCED
        ALTHOUGH THERE ARE SITUATIONS IN WHICH IT WOULD BE SAFE TO DO
        SO. CARE SHOULD BE TAKEN THAT ALL OF THE NEW GRID POINTS LIE
        WITHIN THE ORIGINAL GRID, NO ERROR CHECKS ARE MADE.
 
 
W3lib.tar Library contains Fortran 90 decoder/encoder routines for GRIB edition 1. (Fortran90)
Date posted: 2/22/2007