SUBROUTINE POLATES4(IPOPT,KGDSI,KGDSO,MI,MO,KM,IBI,LI,GI, &
NO,RLAT,RLON,IBO,LO,GO,IRET)
!$$$ SUBPROGRAM DOCUMENTATION BLOCK
!
! SUBPROGRAM: POLATES4 INTERPOLATE SCALAR FIELDS (SPECTRAL)
! PRGMMR: IREDELL ORG: W/NMC23 DATE: 96-04-10
!
! ABSTRACT: THIS SUBPROGRAM PERFORMS SPECTRAL INTERPOLATION
! FROM ANY GRID TO ANY GRID FOR SCALAR FIELDS.
! IT REQUIRES THAT THE INPUT FIELDS BE UNIFORMLY GLOBAL.
! OPTIONS ALLOW CHOICES BETWEEN TRIANGULAR SHAPE (IPOPT(1)=0)
! AND RHOMBOIDAL SHAPE (IPOPT(1)=1) WHICH HAS NO DEFAULT;
! A SECOND OPTION IS THE TRUNCATION (IPOPT(2)) WHICH DEFAULTS
! TO A SENSIBLE TRUNCATION FOR THE INPUT GRID (IF OPT(2)=-1).
! NOTE THAT IF THE OUTPUT GRID IS NOT FOUND IN A SPECIAL LIST,
! THEN THE TRANSFORM BACK TO GRID IS NOT VERY FAST.
! THIS SPECIAL LIST CONTAINS GLOBAL CYLINDRICAL GRIDS,
! POLAR STEREOGRAPHIC GRIDS CENTERED AT THE POLE
! AND MERCATOR GRIDS.
! ONLY HORIZONTAL INTERPOLATION IS PERFORMED.
! THE GRIDS ARE DEFINED BY THEIR GRID DESCRIPTION SECTIONS
! (PASSED IN INTEGER FORM AS DECODED BY SUBPROGRAM W3FI63).
! THE CURRENT CODE RECOGNIZES THE FOLLOWING PROJECTIONS:
! (KGDS(1)=000) EQUIDISTANT CYLINDRICAL
! (KGDS(1)=001) MERCATOR CYLINDRICAL
! (KGDS(1)=003) LAMBERT CONFORMAL CONICAL
! (KGDS(1)=004) GAUSSIAN CYLINDRICAL (SPECTRAL NATIVE)
! (KGDS(1)=005) POLAR STEREOGRAPHIC AZIMUTHAL
! (KGDS(1)=203) ROTATED EQUIDISTANT CYLINDRICAL (E-STAGGER)
! (KGDS(1)=205) ROTATED EQUIDISTANT CYLINDRICAL (B-STAGGER)
! WHERE KGDS COULD BE EITHER INPUT KGDSI OR OUTPUT KGDSO.
! AS AN ADDED BONUS THE NUMBER OF OUTPUT GRID POINTS
! AND THEIR LATITUDES AND LONGITUDES ARE ALSO RETURNED.
! ON THE OTHER HAND, THE OUTPUT CAN BE A SET OF STATION POINTS
! IF KGDSO(1)<0, IN WHICH CASE THE NUMBER OF POINTS
! AND THEIR LATITUDES AND LONGITUDES MUST BE INPUT.
! OUTPUT BITMAPS WILL NOT BE CREATED.
!
! PROGRAM HISTORY LOG:
! 96-04-10 IREDELL
! 2001-06-18 IREDELL IMPROVE DETECTION OF SPECIAL FAST TRANSFORM
! 2015-01-27 GAYNO REPLACE CALLS TO GDSWIZ WITH NEW MERGED
! VERSION OF GDSWZD.
!
! USAGE: CALL POLATES4(IPOPT,KGDSI,KGDSO,MI,MO,KM,IBI,LI,GI,
! & NO,RLAT,RLON,IBO,LO,GO,IRET)
!
! INPUT ARGUMENT LIST:
! IPOPT - INTEGER (20) INTERPOLATION OPTIONS
! IPOPT(1)=0 FOR TRIANGULAR, IPOPT(1)=1 FOR RHOMBOIDAL;
! IPOPT(2) IS TRUNCATION NUMBER
! (DEFAULTS TO SENSIBLE IF IPOPT(2)=-1).
! KGDSI - INTEGER (200) INPUT GDS PARAMETERS AS DECODED BY W3FI63
! KGDSO - INTEGER (200) OUTPUT GDS PARAMETERS
! (KGDSO(1)<0 IMPLIES RANDOM STATION POINTS)
! MI - INTEGER SKIP NUMBER BETWEEN INPUT GRID FIELDS IF KM>1
! OR DIMENSION OF INPUT GRID FIELDS IF KM=1
! MO - INTEGER SKIP NUMBER BETWEEN OUTPUT GRID FIELDS IF KM>1
! OR DIMENSION OF OUTPUT GRID FIELDS IF KM=1
! KM - INTEGER NUMBER OF FIELDS TO INTERPOLATE
! IBI - INTEGER (KM) INPUT BITMAP FLAGS (MUST BE ALL 0)
! LI - LOGICAL*1 (MI,KM) INPUT BITMAPS (IF SOME IBI(K)=1)
! GI - REAL (MI,KM) INPUT FIELDS TO INTERPOLATE
! NO - INTEGER NUMBER OF OUTPUT POINTS (ONLY IF KGDSO(1)<0)
! RLAT - REAL (NO) OUTPUT LATITUDES IN DEGREES (IF KGDSO(1)<0)
! RLON - REAL (NO) OUTPUT LONGITUDES IN DEGREES (IF KGDSO(1)<0)
!
! OUTPUT ARGUMENT LIST:
! NO - INTEGER NUMBER OF OUTPUT POINTS (ONLY IF KGDSO(1)>=0)
! RLAT - REAL (MO) OUTPUT LATITUDES IN DEGREES (IF KGDSO(1)>=0)
! RLON - REAL (MO) OUTPUT LONGITUDES IN DEGREES (IF KGDSO(1)>=0)
! IBO - INTEGER (KM) OUTPUT BITMAP FLAGS
! LO - LOGICAL*1 (MO,KM) OUTPUT BITMAPS (ALWAYS OUTPUT)
! GO - REAL (MO,KM) OUTPUT FIELDS INTERPOLATED
! IRET - INTEGER RETURN CODE
! 0 SUCCESSFUL INTERPOLATION
! 2 UNRECOGNIZED INPUT GRID OR NO GRID OVERLAP
! 3 UNRECOGNIZED OUTPUT GRID
! 41 INVALID NONGLOBAL INPUT GRID
! 42 INVALID SPECTRAL METHOD PARAMETERS
!
! SUBPROGRAMS CALLED:
! GDSWZD GRID DESCRIPTION SECTION WIZARD
! SPTRUN SPECTRALLY TRUNCATE GRIDDED SCALAR FIELDS
! SPTRUNS SPECTRALLY INTERPOLATE SCALARS TO POLAR STEREO.
! SPTRUNM SPECTRALLY INTERPOLATE SCALARS TO MERCATOR
! SPTRUNG SPECTRALLY INTERPOLATE SCALARS TO STATIONS
!
! ATTRIBUTES:
! LANGUAGE: FORTRAN 90
!
!$$$
USE GDSWZD_MOD
!
IMPLICIT NONE
!
INTEGER, INTENT(IN ) :: IPOPT(20), KGDSI(200)
INTEGER, INTENT(IN ) :: KGDSO(200), MI, MO
INTEGER, INTENT(IN ) :: IBI(KM), KM
INTEGER, INTENT( OUT) :: IBO(KM), IRET
!
LOGICAL*1, INTENT(IN ) :: LI(MI,KM)
LOGICAL*1, INTENT( OUT) :: LO(MO,KM)
!
REAL, INTENT(IN ) :: GI(MI,KM)
REAL, INTENT(INOUT) :: RLAT(MO),RLON(MO)
REAL, INTENT( OUT) :: GO(MO,KM)
!
REAL, PARAMETER :: FILL=-9999.
REAL, PARAMETER :: RERTH=6.3712E6
REAL, PARAMETER :: PI=3.14159265358979
REAL, PARAMETER :: DPR=180./PI
!
INTEGER :: IDRTI, IDRTO, IG, JG, IM, JM
INTEGER :: IGO, JGO, IMO, JMO
INTEGER :: ISCAN, JSCAN, NSCAN
INTEGER :: ISCANO, JSCANO, NSCANO
INTEGER :: ISKIPI, JSKIPI
INTEGER :: IMAXI, JMAXI, ISPEC
INTEGER :: IP, IPRIME, IPROJ, IROMB, K
INTEGER :: MAXWV, N, NI, NJ, NPS, NO
!
REAL :: DE, DR, DY
REAL :: DLAT, DLON, DLATO, DLONO
REAL :: GO2(MO,KM), H, HI, HJ
REAL :: ORIENT
REAL :: RLAT1, RLON1, RLAT2, RLON2, RLATI
REAL :: XMESH, XP, YP
REAL :: XPTS(MO), YPTS(MO)
! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
! 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)
IF(NO.EQ.0) IRET=3
ENDIF
! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
! AFFIRM APPROPRIATE INPUT GRID
! LAT/LON OR GAUSSIAN
! NO BITMAPS
! FULL ZONAL COVERAGE
! FULL MERIDIONAL COVERAGE
IDRTI=KGDSI(1)
IM=KGDSI(2)
JM=KGDSI(3)
RLON1=KGDSI(5)*1.E-3
RLON2=KGDSI(8)*1.E-3
ISCAN=MOD(KGDSI(11)/128,2)
JSCAN=MOD(KGDSI(11)/64,2)
NSCAN=MOD(KGDSI(11)/32,2)
IF(IDRTI.NE.0.AND.IDRTI.NE.4) IRET=41
DO K=1,KM
IF(IBI(K).NE.0) IRET=41
ENDDO
IF(IRET.EQ.0) THEN
IF(ISCAN.EQ.0) THEN
DLON=(MOD(RLON2-RLON1-1+3600,360.)+1)/(IM-1)
ELSE
DLON=-(MOD(RLON1-RLON2-1+3600,360.)+1)/(IM-1)
ENDIF
IG=NINT(360/ABS(DLON))
IPRIME=1+MOD(-NINT(RLON1/DLON)+IG,IG)
IMAXI=IG
JMAXI=JM
IF(MOD(IG,2).NE.0.OR.IM.LT.IG) IRET=41
ENDIF
IF(IRET.EQ.0.AND.IDRTI.EQ.0) THEN
RLAT1=KGDSI(4)*1.E-3
RLAT2=KGDSI(7)*1.E-3
DLAT=(RLAT2-RLAT1)/(JM-1)
JG=NINT(180/ABS(DLAT))
IF(JM.EQ.JG) IDRTI=256
IF(JM.NE.JG.AND.JM.NE.JG+1) IRET=41
ELSEIF(IRET.EQ.0.AND.IDRTI.EQ.4) THEN
JG=KGDSI(10)*2
IF(JM.NE.JG) IRET=41
ENDIF
! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
! SET PARAMETERS
IF(IRET.EQ.0) THEN
IROMB=IPOPT(1)
MAXWV=IPOPT(2)
IF(MAXWV.EQ.-1) THEN
IF(IROMB.EQ.0.AND.IDRTI.EQ.4) MAXWV=(JMAXI-1)
IF(IROMB.EQ.1.AND.IDRTI.EQ.4) MAXWV=(JMAXI-1)/2
IF(IROMB.EQ.0.AND.IDRTI.EQ.0) MAXWV=(JMAXI-3)/2
IF(IROMB.EQ.1.AND.IDRTI.EQ.0) MAXWV=(JMAXI-3)/4
IF(IROMB.EQ.0.AND.IDRTI.EQ.256) MAXWV=(JMAXI-1)/2
IF(IROMB.EQ.1.AND.IDRTI.EQ.256) MAXWV=(JMAXI-1)/4
ENDIF
IF((IROMB.NE.0.AND.IROMB.NE.1).OR.MAXWV.LT.0) IRET=42
ENDIF
! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
! INTERPOLATE
IF(IRET.EQ.0) THEN
IF(NSCAN.EQ.0) THEN
ISKIPI=1
JSKIPI=IM
ELSE
ISKIPI=JM
JSKIPI=1
ENDIF
IF(ISCAN.EQ.1) ISKIPI=-ISKIPI
IF(JSCAN.EQ.0) JSKIPI=-JSKIPI
ISPEC=0
! SPECIAL CASE OF GLOBAL CYLINDRICAL GRID
IF((KGDSO(1).EQ.0.OR.KGDSO(1).EQ.4).AND. &
MOD(KGDSO(2),2).EQ.0.AND.KGDSO(5).EQ.0.AND.KGDSO(11).EQ.0) THEN
IDRTO=KGDSO(1)
IMO=KGDSO(2)
JMO=KGDSO(3)
RLON2=KGDSO(8)*1.E-3
DLONO=(MOD(RLON2-1+3600,360.)+1)/(IMO-1)
IGO=NINT(360/ABS(DLONO))
IF(IMO.EQ.IGO.AND.IDRTO.EQ.0) THEN
RLAT1=KGDSO(4)*1.E-3
RLAT2=KGDSO(7)*1.E-3
DLAT=(RLAT2-RLAT1)/(JMO-1)
JGO=NINT(180/ABS(DLAT))
IF(JMO.EQ.JGO) IDRTO=256
IF(JMO.EQ.JGO.OR.JMO.EQ.JGO+1) ISPEC=1
ELSEIF(IMO.EQ.IGO.AND.IDRTO.EQ.4) THEN
JGO=KGDSO(10)*2
IF(JMO.EQ.JGO) ISPEC=1
ENDIF
IF(ISPEC.EQ.1) THEN
CALL SPTRUN(IROMB,MAXWV,IDRTI,IMAXI,JMAXI,IDRTO,IMO,JMO, &
KM,IPRIME,ISKIPI,JSKIPI,MI,0,0,MO,0,GI,GO)
ENDIF
! SPECIAL CASE OF POLAR STEREOGRAPHIC GRID
ELSEIF(KGDSO(1).EQ.5.AND. &
KGDSO(2).EQ.KGDSO(3).AND.MOD(KGDSO(2),2).EQ.1.AND. &
KGDSO(8).EQ.KGDSO(9).AND.KGDSO(11).EQ.64) THEN
NPS=KGDSO(2)
RLAT1=KGDSO(4)*1.E-3
RLON1=KGDSO(5)*1.E-3
ORIENT=KGDSO(7)*1.E-3
XMESH=KGDSO(8)
IPROJ=MOD(KGDSO(10)/128,2)
IP=(NPS+1)/2
H=(-1.)**IPROJ
DE=(1.+SIN(60./DPR))*RERTH
DR=DE*COS(RLAT1/DPR)/(1+H*SIN(RLAT1/DPR))
XP=1-H*SIN((RLON1-ORIENT)/DPR)*DR/XMESH
YP=1+COS((RLON1-ORIENT)/DPR)*DR/XMESH
IF(NINT(XP).EQ.IP.AND.NINT(YP).EQ.IP) THEN
IF(IPROJ.EQ.0) THEN
CALL SPTRUNS(IROMB,MAXWV,IDRTI,IMAXI,JMAXI,KM,NPS, &
IPRIME,ISKIPI,JSKIPI,MI,MO,0,0,0, &
60.,XMESH,ORIENT,GI,GO,GO2)
ELSE
CALL SPTRUNS(IROMB,MAXWV,IDRTI,IMAXI,JMAXI,KM,NPS, &
IPRIME,ISKIPI,JSKIPI,MI,MO,0,0,0, &
60.,XMESH,ORIENT,GI,GO2,GO)
ENDIF
ISPEC=1
ENDIF
! SPECIAL CASE OF MERCATOR GRID
ELSEIF(KGDSO(1).EQ.1) THEN
NI=KGDSO(2)
NJ=KGDSO(3)
RLAT1=KGDSO(4)*1.E-3
RLON1=KGDSO(5)*1.E-3
RLON2=KGDSO(8)*1.E-3
RLATI=KGDSO(9)*1.E-3
ISCANO=MOD(KGDSO(11)/128,2)
JSCANO=MOD(KGDSO(11)/64,2)
NSCANO=MOD(KGDSO(11)/32,2)
DY=KGDSO(13)
HI=(-1.)**ISCANO
HJ=(-1.)**(1-JSCANO)
DLONO=HI*(MOD(HI*(RLON2-RLON1)-1+3600,360.)+1)/(NI-1)
DLATO=HJ*DY/(RERTH*COS(RLATI/DPR))*DPR
IF(NSCANO.EQ.0) THEN
CALL SPTRUNM(IROMB,MAXWV,IDRTI,IMAXI,JMAXI,KM,NI,NJ, &
IPRIME,ISKIPI,JSKIPI,MI,MO,0,0,0, &
RLAT1,RLON1,DLATO,DLONO,GI,GO)
ISPEC=1
ENDIF
ENDIF
! GENERAL SLOW CASE
IF(ISPEC.EQ.0) THEN
CALL SPTRUNG(IROMB,MAXWV,IDRTI,IMAXI,JMAXI,KM,NO, &
IPRIME,ISKIPI,JSKIPI,MI,MO,0,0,0,RLAT,RLON,GI,GO)
ENDIF
DO K=1,KM
IBO(K)=0
DO N=1,NO
LO(N,K)=.TRUE.
ENDDO
ENDDO
ELSE
DO K=1,KM
IBO(K)=1
DO N=1,NO
LO(N,K)=.FALSE.
GO(N,K)=0.
ENDDO
ENDDO
ENDIF
! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
END SUBROUTINE POLATES4