C----------------------------------------------------------------------- SUBROUTINE POLATEG0(IPOPT,KGDSI,KGDSO,MI,MO,KM,IBI,LI,GI, & NO,RLAT,RLON,CROT,SROT,IBO,LO,XO,YO,IRET) C$$$ SUBPROGRAM DOCUMENTATION BLOCK C C SUBPROGRAM: POLATEG0 INTERPOLATE SCALAR FIELD GRADIENTS (BILINEAR) C PRGMMR: IREDELL ORG: W/NMC23 DATE: 96-04-10 C C ABSTRACT: THIS SUBPROGRAM PERFORMS BILINEAR INTERPOLATION C FROM ANY GRID TO ANY GRID FOR SCALAR FIELDS, C RETURNING THEIR VECTOR GRADIENTS. C NO OPTIONS ARE ALLOWED. C ONLY HORIZONTAL INTERPOLATION IS PERFORMED. C THE GRIDS ARE DEFINED BY THEIR GRID DESCRIPTION SECTIONS C (PASSED IN INTEGER FORM AS DECODED BY SUBPROGRAM W3FI63). C THE CURRENT CODE RECOGNIZES THE FOLLOWING PROJECTIONS: C (KGDS(1)=000) EQUIDISTANT CYLINDRICAL C (KGDS(1)=001) MERCATOR CYLINDRICAL C (KGDS(1)=003) LAMBERT CONFORMAL CONICAL C (KGDS(1)=004) GAUSSIAN CYLINDRICAL (SPECTRAL NATIVE) C (KGDS(1)=005) POLAR STEREOGRAPHIC AZIMUTHAL C (KGDS(1)=202) ROTATED EQUIDISTANT CYLINDRICAL (ETA NATIVE) C WHERE KGDS COULD BE EITHER INPUT KGDSI OR OUTPUT KGDSO. C AS AN ADDED BONUS THE NUMBER OF OUTPUT GRID POINTS C AND THEIR LATITUDES AND LONGITUDES ARE ALSO RETURNED. C ON THE OTHER HAND, THE OUTPUT CAN BE A SET OF STATION POINTS C IF KGDSO(1)<0, IN WHICH CASE THE NUMBER OF POINTS C AND THEIR LATITUDES AND LONGITUDES MUST BE INPUT. C INPUT BITMAPS WILL BE INTERPOLATED TO OUTPUT BITMAPS. C OUTPUT BITMAPS WILL ALSO BE CREATED WHEN THE OUTPUT GRID C EXTENDS OUTSIDE OF THE DOMAIN OF THE INPUT GRID. C THE OUTPUT FIELD IS SET TO 0 WHERE THE OUTPUT BITMAP IS OFF. C C PROGRAM HISTORY LOG: C 96-04-10 IREDELL C 1999-04-08 IREDELL SPLIT IJKGDS INTO TWO PIECES C 2001-06-18 IREDELL FIXED CALL TO IJKGDS1 C C USAGE: CALL POLATEG0(IPOPT,KGDSI,KGDSO,MI,MO,KM,IBI,LI,GI, C & NO,RLAT,RLON,CROT,SROT,IBO,LO,XO,YO,IRET) C C INPUT ARGUMENT LIST: C IPOPT - INTEGER (20) INTERPOLATION OPTIONS (NO OPTIONS) C KGDSI - INTEGER (200) INPUT GDS PARAMETERS AS DECODED BY W3FI63 C KGDSO - INTEGER (200) OUTPUT GDS PARAMETERS C (KGDSO(1)<0 IMPLIES RANDOM STATION POINTS) C MI - INTEGER SKIP NUMBER BETWEEN INPUT GRID FIELDS IF KM>1 C OR DIMENSION OF INPUT GRID FIELDS IF KM=1 C MO - INTEGER SKIP NUMBER BETWEEN OUTPUT GRID FIELDS IF KM>1 C OR DIMENSION OF OUTPUT GRID FIELDS IF KM=1 C KM - INTEGER NUMBER OF FIELDS TO INTERPOLATE C IBI - INTEGER (KM) INPUT BITMAP FLAGS C LI - LOGICAL*1 (MI,KM) INPUT BITMAPS (IF SOME IBI(K)=1) C GI - REAL (MI,KM) INPUT FIELDS TO INTERPOLATE C NO - INTEGER NUMBER OF OUTPUT POINTS (ONLY IF KGDSO(1)<0) C RLAT - REAL (NO) OUTPUT LATITUDES IN DEGREES (IF KGDSO(1)<0) C RLON - REAL (NO) OUTPUT LONGITUDES IN DEGREES (IF KGDSO(1)<0) C CROT - REAL (NO) VECTOR ROTATION COSINES (IF KGDSO(1)<0) C SROT - REAL (NO) VECTOR ROTATION SINES (IF KGDSO(1)<0) C (UGRID=CROT*UEARTH-SROT*VEARTH; C VGRID=SROT*UEARTH+CROT*VEARTH) C C OUTPUT ARGUMENT LIST: C NO - INTEGER NUMBER OF OUTPUT POINTS (ONLY IF KGDSO(1)>=0) C RLAT - REAL (MO) OUTPUT LATITUDES IN DEGREES (IF KGDSO(1)>=0) C RLON - REAL (MO) OUTPUT LONGITUDES IN DEGREES (IF KGDSO(1)>=0) C IBO - INTEGER (KM) OUTPUT BITMAP FLAGS C LO - LOGICAL*1 (MO,KM) OUTPUT BITMAPS (ALWAYS OUTPUT) C XO - REAL (MO,KM) OUTPUT X-GRADIENT FIELDS INTERPOLATED C YO - REAL (MO,KM) OUTPUT Y-GRADIENT FIELDS INTERPOLATED C IRET - INTEGER RETURN CODE C 0 SUCCESSFUL INTERPOLATION C 2 UNRECOGNIZED INPUT GRID OR NO GRID OVERLAP C 3 UNRECOGNIZED OUTPUT GRID C C SUBPROGRAMS CALLED: C GDSWZD GRID DESCRIPTION SECTION WIZARD C IJKGDS0 SET UP PARAMETERS FOR IJKGDS1 C (IJKGDS1) RETURN FIELD POSITION FOR A GIVEN GRID POINT C POLFIXS MAKE MULTIPLE POLE SCALAR VALUES CONSISTENT C C REMARKS: THE GRADIENT COMPUTATIONS ARE NOT ROBUST NEAR THE POLES. C IN FACT, NO GRADIENTS ARE COMPUTED POLEWARD OF 89 LATITUDE. C C ATTRIBUTES: C LANGUAGE: FORTRAN 77 C C$$$ CFPP$ EXPAND(IJKGDS1) INTEGER IPOPT(20) INTEGER KGDSI(200),KGDSO(200) INTEGER IBI(KM),IBO(KM) LOGICAL*1 LI(MI,KM),LO(MO,KM) REAL GI(MI,KM),XO(MO,KM),YO(MO,KM) REAL RLAT(MO),RLON(MO) REAL CROT(MO),SROT(MO) REAL CLAT(MO) REAL XPTS(MO),YPTS(MO) REAL XLON(MO),XLAT(MO) REAL YLON(MO),YLAT(MO) INTEGER N11(MO),N21(MO),N12(MO),N22(MO) REAL WX11(MO),WX21(MO),WX12(MO),WX22(MO) REAL WY11(MO),WY21(MO),WY12(MO),WY22(MO) INTEGER IJKGDSA(20) PARAMETER(FILL=-9999.) PARAMETER(PLAT=89.) PARAMETER(RERTH=6.3712E6) C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - C COMPUTE NUMBER OF OUTPUT POINTS AND THEIR LATITUDES AND LONGITUDES. IRET=0 IF(KGDSO(1).GE.0) THEN CALL GDSWZD(KGDSO, 0,MO,FILL,XPTS,YPTS,RLON,RLAT,NO,1,CROT,SROT, & 0,XLON,XLAT,YLON,YLAT) IF(NO.EQ.0) IRET=3 ENDIF C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - C LOCATE INPUT POINTS AND COMPUTE THEIR WEIGHTS DPR=180/ACOS(-1.) DO N=1,NO CLAT(N)=COS(RLAT(N)/DPR) ENDDO CALL GDSWZD(KGDSI,-1,NO,FILL,XPTS,YPTS,RLON,RLAT,NV,0,DUM,DUM, & 1,XLON,XLAT,YLON,YLAT) IF(IRET.EQ.0.AND.NV.EQ.0) IRET=2 CALL IJKGDS0(KGDSI,IJKGDSA) DO N=1,NO XI=XPTS(N) YI=YPTS(N) IF(XI.NE.FILL.AND.YI.NE.FILL.AND.ABS(RLAT(N)).LE.PLAT) THEN I1=XI I2=I1+1 J1=YI J2=J1+1 XF=XI-I1 YF=YI-J1 N11(N)=IJKGDS1(I1,J1,IJKGDSA) N21(N)=IJKGDS1(I2,J1,IJKGDSA) N12(N)=IJKGDS1(I1,J2,IJKGDSA) N22(N)=IJKGDS1(I2,J2,IJKGDSA) IF(MIN(N11(N),N21(N),N12(N),N22(N)).GT.0) THEN FACX=DPR/(RERTH*CLAT(N)) WX11(N)=(-(1-YF)*XLON(N)-(1-XF)*YLON(N))*FACX WX21(N)=((1-YF)*XLON(N)-XF*YLON(N))*FACX WX12(N)=(-YF*XLON(N)+(1-XF)*YLON(N))*FACX WX22(N)=(YF*XLON(N)+XF*YLON(N))*FACX FACY=DPR/RERTH WY11(N)=(-(1-YF)*XLAT(N)-(1-XF)*YLAT(N))*FACY WY21(N)=((1-YF)*XLAT(N)-XF*YLAT(N))*FACY WY12(N)=(-YF*XLAT(N)+(1-XF)*YLAT(N))*FACY WY22(N)=(YF*XLAT(N)+XF*YLAT(N))*FACY ELSE N11(N)=0 N21(N)=0 N12(N)=0 N22(N)=0 ENDIF ELSE N11(N)=0 N21(N)=0 N12(N)=0 N22(N)=0 ENDIF ENDDO C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - C INTERPOLATE WITH OR WITHOUT BITMAPS CMIC$ DO ALL AUTOSCOPE DO K=1,KM IBO(K)=0 DO N=1,NO LO(N,K)=N11(N).GT.0.AND.(IBI(K).EQ.0.OR. & (LI(N11(N),K).AND.LI(N21(N),K).AND. & LI(N12(N),K).AND.LI(N22(N),K))) IF(LO(N,K)) THEN XO(N,K)=WX11(N)*GI(N11(N),K)+WX21(N)*GI(N21(N),K) & +WX12(N)*GI(N12(N),K)+WX22(N)*GI(N22(N),K) YO(N,K)=WY11(N)*GI(N11(N),K)+WY21(N)*GI(N21(N),K) & +WY12(N)*GI(N12(N),K)+WY22(N)*GI(N22(N),K) XROT=CROT(N)*XO(N,K)-SROT(N)*YO(N,K) YROT=SROT(N)*XO(N,K)+CROT(N)*YO(N,K) XO(N,K)=XROT YO(N,K)=YROT ELSE IBO(K)=1 XO(N,K)=0. YO(N,K)=0. ENDIF ENDDO ENDDO IF(KGDSO(1).EQ.0) CALL POLFIXV(NO,MO,KM,RLAT,RLON,IBO,LO,XO,YO) C - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - END