read_subsets.f

      program  read_subsets

      implicit none

C

C     Parameter declaration.

C

      character*7  FILE_NAME

      parameter   (FILE_NAME  = 'SDS.hdf')

      integer      DFACC_READ, DFNT_INT32

      parameter   (DFACC_READ = 1,

     +             DFNT_INT32 = 24)

      integer      SUB1_LENGTH, SUB2_LENGTH, SUB3_LENGTH1,

     +             SUB3_LENGTH2 

      parameter   (SUB1_LENGTH  = 5,

     +             SUB2_LENGTH  = 4, 

     +             SUB3_LENGTH1 = 2,

     +             SUB3_LENGTH2 = 3)

C

C     Function declaration.

C

      integer sfstart, sfselect, sfrdata, sfendacc, sfend

C

C**** Variable declaration *******************************************

C

      integer sd_id, sds_id, sds_index, status

      integer start(2), edges(2), stride(2)

      integer sub1_data(SUB1_LENGTH)

      integer sub2_data(SUB2_LENGTH)

      integer sub3_data(SUB3_LENGTH1,SUB3_LENGTH2)

      integer i, j

C

C**** End of variable declaration ************************************

C

C

C     Open the file and initialize the SD interface.

C

      sd_id = sfstart(FILE_NAME, DFACC_READ)

C

C     Select the first data set.

C

      sds_index = 0

      sds_id =sfselect(sd_id, sds_index)

C

C            Reading the first subset.

C

C     Set elements of start, stride, and edges arrays to read 

C     every 3d element in in the 2nd row starting in the 4th column. 

C

      start(1) = 1 

      start(2) = 3 

      edges(1) = 1 

      edges(2) = SUB1_LENGTH

      stride(1) = 1

      stride(2) = 3 

C

C     Read the data from sub1_data array. 

C

      status = sfrdata(sds_id, start, stride, edges, sub1_data)

C

C     Print what we have just read, the following numbers should be displayed:

C

C           5 8 1000 14 17 

C

      write(*,*) (sub1_data(j), j = 1, SUB1_LENGTH)

C

C            Reading the second subset.

C

C     Set elements of start, stride, and edges arrays to read 

C     first 4 elements of 10th column. 

C

      start(1) = 0 

      start(2) = 9 

      edges(1) = SUB2_LENGTH 

      edges(2) = 1 

      stride(1) = 1

      stride(2) = 1 

C

C     Read the data into sub2_data array. 

C

      status = sfrdata(sds_id, start, stride, edges, sub2_data)

C

C     Print what we have just read; the following numbers should be displayed:

C

C          10 1000 12 13 

C

      write(*,*) (sub2_data(j), j = 1, SUB2_LENGTH)

C

C            Reading the third subset.

C

C     Set elements of start, stride and edges arrays to read 

C     every 6th element in the row and every 4th element in the column

C     starting at 1st row, 3rd column.  

C

      start(1) = 0 

      start(2) = 2 

      edges(1) = SUB3_LENGTH1 

      edges(2) = SUB3_LENGTH2 

      stride(1) = 4 

      stride(2) = 6 

C

C     Read the data from the file into sub3_data array. 

C

      status = sfrdata(sds_id, start, stride, edges, sub3_data)

C

C     Print what we have just read; the following numbers should be displayed:

C

C         3 9 15

C         7 13 19 

C

      do 50 i = 1, SUB3_LENGTH1

         write(*,*) (sub3_data(i,j), j = 1, SUB3_LENGTH2)

50    continue    

C

C     Terminate access to the data set.

C

      status = sfendacc(sds_id)

C

C     Terminate access to the SD interface and close the file.

C

      status = sfend(sd_id)

      end