gf_getfld.f

计算线性趋势 回归系数 主要用于气象站点值的线性趋势计算

      subroutine gf_getfld(cgrib,lcgrib,ifldnum,unpack,expand,gfld,ierr)
!$$$  SUBPROGRAM DOCUMENTATION BLOCK
!                .      .    .                                       .
! SUBPROGRAM:    gf_getfld 
!   PRGMMR: Gilbert         ORG: W/NP11    DATE: 2000-05-26
!
! ABSTRACT: This subroutine returns the Grid Definition, Product Definition,
!   Bit-map ( if applicable ), and the unpacked data for a given data
!   field.  All of the information returned is stored in a derived
!   type variable, gfld.  Gfld is of type gribfield, which is defined
!   in module grib_mod, so users of this routine will need to include
!   the line "USE GRIB_MOD" in their calling routine.  Each component of the 
!   gribfield type is described in the OUTPUT ARGUMENT LIST section below.
!
!   Since there can be multiple data fields packed into a GRIB2
!   message, the calling routine indicates which field is being requested
!   with the ifldnum argument.
!
! PROGRAM HISTORY LOG:
! 2000-05-26  Gilbert
! 2002-01-24  Gilbert  - Changed to pass back derived type gribfield
!                        variable through argument list, instead of
!                        having many different arguments.
! 2004-05-20  Gilbert  - Added check to see if previous a bit-map is specified,
!                        but none was found.
!
! USAGE:    CALL gf_getfld(cgrib,lcgrib,ifldnum,unpack,expand,gfld,ierr)
!   INPUT ARGUMENT LIST:
!     cgrib    - Character array that contains the GRIB2 message
!     lcgrib   - Length (in bytes) of GRIB message array cgrib.
!     ifldnum  - Specifies which field in the GRIB2 message to return.
!     unpack   - Logical value indicating whether to unpack bitmap/data
!                .true. = unpack bitmap and data values
!                .false. = do not unpack bitmap and data values
!     expand   - Boolean value indicating whether the data points should be
!                expanded to the correspond grid, if a bit-map is present.
!                1 = if possible, expand data field to grid, inserting zero
!                    values at gridpoints that are bitmapped out.
!                    (SEE REMARKS2)
!                0 = do not expand data field, leaving it an array of
!                    consecutive data points for each "1" in the bitmap.
!                This argument is ignored if unpack == 0 OR if the
!                returned field does not contain a bit-map.
!
!   OUTPUT ARGUMENT LIST:      
!     gfld - derived type gribfield ( defined in module grib_mod )
!            ( NOTE: See Remarks Section )
!        gfld%version = GRIB edition number ( currently 2 )
!        gfld%discipline = Message Discipline ( see Code Table 0.0 )
!        gfld%idsect() = Contains the entries in the Identification
!                        Section ( Section 1 )
!                        This element is actually a pointer to an array
!                        that holds the data.
!            gfld%idsect(1)  = Identification of originating Centre 
!                                    ( see Common Code Table C-1 )
!                             7 - US National Weather Service
!            gfld%idsect(2)  = Identification of originating Sub-centre
!            gfld%idsect(3)  = GRIB Master Tables Version Number
!                                    ( see Code Table 1.0 )
!                             0 - Experimental
!                             1 - Initial operational version number
!            gfld%idsect(4)  = GRIB Local Tables Version Number
!                                    ( see Code Table 1.1 )
!                             0     - Local tables not used
!                             1-254 - Number of local tables version used
!            gfld%idsect(5)  = Significance of Reference Time (Code Table 1.2)
!                             0 - Analysis
!                             1 - Start of forecast
!                             2 - Verifying time of forecast
!                             3 - Observation time
!            gfld%idsect(6)  = Year ( 4 digits )
!            gfld%idsect(7)  = Month
!            gfld%idsect(8)  = Day
!            gfld%idsect(9)  = Hour
!            gfld%idsect(10)  = Minute
!            gfld%idsect(11)  = Second
!            gfld%idsect(12)  = Production status of processed data
!                                    ( see Code Table 1.3 )
!                              0 - Operational products
!                              1 - Operational test products
!                              2 - Research products
!                              3 - Re-analysis products
!            gfld%idsect(13)  = Type of processed data ( see Code Table 1.4 )
!                              0  - Analysis products
!                              1  - Forecast products
!                              2  - Analysis and forecast products
!                              3  - Control forecast products
!                              4  - Perturbed forecast products
!                              5  - Control and perturbed forecast products
!                              6  - Processed satellite observations
!                              7  - Processed radar observations
!        gfld%idsectlen = Number of elements in gfld%idsect().
!        gfld%local() = Pointer to character array containing contents
!                       of Local Section 2, if included
!        gfld%locallen = length of array gfld%local()
!        gfld%ifldnum = field number within GRIB message
!        gfld%griddef = Source of grid definition (see Code Table 3.0)
!                      0 - Specified in Code table 3.1
!                      1 - Predetermined grid Defined by originating centre
!        gfld%ngrdpts = Number of grid points in the defined grid.
!        gfld%numoct_opt = Number of octets needed for each 
!                          additional grid points definition.  
!                          Used to define number of
!                          points in each row ( or column ) for
!                          non-regular grids.  
!                          = 0, if using regular grid.
!        gfld%interp_opt = Interpretation of list for optional points 
!                          definition.  (Code Table 3.11)
!        gfld%igdtnum = Grid Definition Template Number (Code Table 3.1)
!        gfld%igdtmpl() = Contains the data values for the specified Grid 
!                         Definition Template ( NN=gfld%igdtnum ).  Each 
!                         element of this integer array contains an entry (in 
!                         the order specified) of Grid Defintion Template 3.NN
!                         This element is actually a pointer to an array
!                         that holds the data.
!        gfld%igdtlen = Number of elements in gfld%igdtmpl().  i.e. number of
!                       entries in Grid Defintion Template 3.NN  
!                       ( NN=gfld%igdtnum ).
!        gfld%list_opt() = (Used if gfld%numoct_opt .ne. 0)  This array 
!                          contains the number of grid points contained in 
!                          each row ( or column ).  (part of Section 3)
!                          This element is actually a pointer to an array
!                          that holds the data.  This pointer is nullified
!                          if gfld%numoct_opt=0.
!        gfld%num_opt = (Used if gfld%numoct_opt .ne. 0)  The number of entries
!                       in array ideflist.  i.e. number of rows ( or columns )
!                       for which optional grid points are defined.  This value
!                       is set to zero, if gfld%numoct_opt=0.
!        gfdl%ipdtnum = Product Definition Template Number (see Code Table 4.0)
!        gfld%ipdtmpl() = Contains the data values for the specified Product 
!                         Definition Template ( N=gfdl%ipdtnum ).  Each element
!                         of this integer array contains an entry (in the 
!                         order specified) of Product Defintion Template 4.N.
!                         This element is actually a pointer to an array
!                         that holds the data.
!        gfld%ipdtlen = Number of elements in gfld%ipdtmpl().  i.e. number of
!                       entries in Product Defintion Template 4.N  
!                       ( N=gfdl%ipdtnum ).
!        gfld%coord_list() = Real array containing floating point values 
!                            intended to document the vertical discretisation
!                            associated to model data on hybrid coordinate
!                            vertical levels.  (part of Section 4)
!                            This element is actually a pointer to an array
!                            that holds the data.
!        gfld%num_coord = number of values in array gfld%coord_list().
!        gfld%ndpts = Number of data points unpacked and returned.
!        gfld%idrtnum = Data Representation Template Number 
!                       ( see Code Table 5.0)
!        gfld%idrtmpl() = Contains the data values for the specified Data 
!                         Representation Template ( N=gfld%idrtnum ).  Each 
!                         element of this integer array contains an entry 
!                         (in the order specified) of Product Defintion 
!                         Template 5.N.
!                         This element is actually a pointer to an array
!                         that holds the data.
!        gfld%idrtlen = Number of elements in gfld%idrtmpl().  i.e. number 
!                       of entries in Data Representation Template 5.N 
!                       ( N=gfld%idrtnum ).
!        gfld%unpacked = logical value indicating whether the bitmap and
!                        data values were unpacked.  If false, 
!                        gfld%bmap and gfld%fld pointers are nullified.
!        gfld%expanded = Logical value indicating whether the data field
!                         was expanded to the grid in the case where a
!                         bit-map is present.  If true, the data points in
!                         gfld%fld match the grid points and zeros were
!                         inserted at grid points where data was bit-mapped
!                         out.  If false, the data values in gfld%fld were
!                         not expanded to the grid and are just a consecutive
!                         array of data points corresponding to each value of
!                         "1" in gfld%bmap.
!        gfld%ibmap = Bitmap indicator ( see Code Table 6.0 )
!                     0 = bitmap applies and is included in Section 6.
!                     1-253 = Predefined bitmap applies
!                     254 = Previously defined bitmap applies to this field
!                     255 = Bit map does not apply to this product.
!        gfld%bmap() = Logical*1 array containing decoded bitmap, 
!                      if ibmap=0 or ibap=254.  Otherwise nullified.
!                      This element is actually a pointer to an array
!                      that holds the data.
!        gfld%fld() = Array of gfld%ndpts unpacked data points.
!                     This element is actually a pointer to an array
!                     that holds the data.
!     ierr     - Error return code.
!                0 = no error
!                1 = Beginning characters "GRIB" not found.
!                2 = GRIB message is not Edition 2.
!                3 = The data field request number was not positive.
!                4 = End string "7777" found, but not where expected.
!                6 = GRIB message did not contain the requested number of
!                    data fields.
!                7 = End string "7777" not found at end of message.
!                8 = Unrecognized Section encountered.
!                9 = Data Representation Template 5.NN not yet implemented.
!               15 = Error unpacking Section 1.
!               16 = Error unpacking Section 2.
!               10 = Error unpacking Section 3.
!               11 = Error unpacking Section 4.
!               12 = Error unpacking Section 5.
!               13 = Error unpacking Section 6.
!               14 = Error unpacking Section 7.
!               17 = Previous bitmap specified, but none exists.
!
! REMARKS: Note that derived type gribfield contains pointers to many
!          arrays of data.  The memory for these arrays is allocated
!          when the values in the arrays are set, to help minimize
!          problems with array overloading.  Because of this users
!          are encouraged to free up this memory, when it is no longer
!          needed, by an explicit call to subroutine gf_free.
!          ( i.e.   CALL GF_FREE(GFLD) )
!
!          Subroutine gb_info can be used to first determine
!          how many data fields exist in a given GRIB message.
!
! REMARKS2: It may not always be possible to expand a bit-mapped data field.
!           If a pre-defined bit-map is used and not included in the GRIB2
!           message itself, this routine would not have the necessary
!           information to expand the data.  In this case, gfld%expanded would
!           would be set to 0 (false), regardless of the value of input
!           argument expand.
!
! ATTRIBUTES:
!   LANGUAGE: Fortran 90
!   MACHINE:  IBM SP
!
!$$$
      use grib_mod
    
      character(len=1),intent(in) :: cgrib(lcgrib)
      integer,intent(in) :: lcgrib,ifldnum
      logical,intent(in) :: unpack,expand
      type(gribfield),intent(out) :: gfld
      integer,intent(out) :: ierr
!      integer,intent(out) :: igds(*),igdstmpl(*),ideflist(*)
!      integer,intent(out) :: ipdsnum,ipdstmpl(*)
!      integer,intent(out) :: idrsnum,idrstmpl(*)
!      integer,intent(out) :: ndpts,ibmap,idefnum,numcoord
!      logical*1,intent(out) :: bmap(*)
!      real,intent(out) :: fld(*),coordlist(*)
      
      character(len=4),parameter :: grib='GRIB',c7777='7777'
      character(len=4) :: ctemp
      real,pointer,dimension(:) :: newfld
      integer:: listsec0(2),igds(5)
      integer iofst,ibeg,istart
      integer(4) :: ieee
      logical*1,pointer,dimension(:) :: bmpsave
      logical have3,have4,have5,have6,have7

      interface
         subroutine gf_unpack1(cgrib,lcgrib,iofst,ids,idslen,ierr)
            character(len=1),intent(in) :: cgrib(lcgrib)
            integer,intent(in) :: lcgrib
            integer,intent(inout) :: iofst
            integer,pointer,dimension(:) :: ids
            integer,intent(out) :: ierr,idslen
         end subroutine gf_unpack1
         subroutine gf_unpack2(cgrib,lcgrib,iofst,lencsec2,csec2,ierr)
            character(len=1),intent(in) :: cgrib(lcgrib)
            integer,intent(in) :: lcgrib
            integer,intent(inout) :: iofst
            integer,intent(out) :: lencsec2
            integer,intent(out) :: ierr
            character(len=1),pointer,dimension(:) :: csec2
         end subroutine gf_unpack2
         subroutine gf_unpack3(cgrib,lcgrib,iofst,igds,igdstmpl,
     &                         mapgridlen,ideflist,idefnum,ierr)
            character(len=1),intent(in) :: cgrib(lcgrib)
            integer,intent(in) :: lcgrib
            integer,intent(inout) :: iofst
            integer,pointer,dimension(:) :: igdstmpl,ideflist
            integer,intent(out) :: igds(5)
            integer,intent(out) :: ierr,idefnum
         end subroutine gf_unpack3
         subroutine gf_unpack4(cgrib,lcgrib,iofst,ipdsnum,ipdstmpl,
     &                      mappdslen,coordlist,numcoord,ierr)
            character(len=1),intent(in) :: cgrib(lcgrib)
            integer,intent(in) :: lcgrib
            integer,intent(inout) :: iofst
            real,pointer,dimension(:) :: coordlist
            integer,pointer,dimension(:) :: ipdstmpl
            integer,intent(out) :: ipdsnum
            integer,intent(out) :: ierr,numcoord
         end subroutine gf_unpack4
         subroutine gf_unpack5(cgrib,lcgrib,iofst,ndpts,idrsnum,
     &                         idrstmpl,mapdrslen,ierr)
            character(len=1),intent(in) :: cgrib(lcgrib)
            integer,intent(in) :: lcgrib
            integer,intent(inout) :: iofst
            integer,intent(out) :: ndpts,idrsnum
            integer,pointer,dimension(:) :: idrstmpl
            integer,intent(out) :: ierr
         end subroutine gf_unpack5
         subroutine gf_unpack6(cgrib,lcgrib,iofst,ngpts,ibmap,bmap,ierr)
            character(len=1),intent(in) :: cgrib(lcgrib)
            integer,intent(in) :: lcgrib,ngpts
            integer,intent(inout) :: iofst
            integer,intent(out) :: ibmap
            integer,intent(out) :: ierr
            logical*1,pointer,dimension(:) :: bmap
         end subroutine gf_unpack6
         subroutine gf_unpack7(cgrib,lcgrib,iofst,igdsnum,igdstmpl,
     &                         idrsnum,idrstmpl,ndpts,fld,ierr)