! f90 easy BYU SIR file format include file
!
! This include file defines an easy record based fortran interface for the
! BYU SIR file format.  A fortran data structure which stores the key
! SIR header information is defined in this file to simplify transfer
! of the SIR information to the various routines.
!
!
! written by DGL  30 Jan. 2002
!
! ***************************************************************
!
!	define a TYPE to hold the standard SIR file header info
!

TYPE :: sirhead
!
!     the following variables are defined in the standard SIR file
!     header (version 3.0) and are fixed length
!
	INTEGER :: nhead         ! number of 512 byte header records
	INTEGER :: nhtype	 ! version number of SIR file header
	INTEGER :: nsx, nsy	 ! image size
	INTEGER :: iopt	         ! projection option
	REAL :: xdeg, ydeg, ascale, bscale, a0, b0 ! projection parameters

	INTEGER :: ixdeg_off, iydeg_off, ideg_sc, iscale_sc ! projection scale
	INTEGER :: ia0_off, ib0_off, i0_sc	            ! factors 

	INTEGER :: idatatype	 ! data storage type
	INTEGER :: ioff, iscale	 ! data storage scale factor and offset value
	REAL :: anodata, vmin, vmax	     ! no data value, visible range
	INTEGER :: iyear, isday, ismin, ieday, iemin ! file time codes
	INTEGER :: iregion, itype, ipol, ifreqhm     ! region id number, etc
	INTEGER :: ispare1	         ! spare integer in header

	CHARACTER (len=100) :: title     ! title for image
	CHARACTER (len=40)  :: sensor	 ! sensor description
	CHARACTER (len=138) :: type	 ! image type description
	CHARACTER (len=100) :: tag	 ! file tag
	CHARACTER (len=100) :: crproc	 ! file creation process name
	CHARACTER (len=28)  :: crtime	 ! file createion time/date
!
!     After the first 512 byte header of variables defined above,
!     the SIR file format permits optional additional 512 byte headers
!     containing an optional user-defined string 'descrip' and an 
!     array of INTEGER*2 (kind=2) 'iaopt'.  These may be arbitrarily long, but 
!     are stored in a multiple of 512 byte records).   Here, we have choosen to 
!     store a small number of maximum of MAXDES characters and MAXI 
!     in the type variable integerss.  
!
	INTEGER :: ndes		! number of chars of extra description string
	INTEGER :: ldes	        ! number of 512 records devoted to descript
	INTEGER :: nia	        ! number of extra integerss

! note: some f90 compilers do not like the initializations of MAXDES and MAXI in
!       the type definition.  If this is the case, remove the initializations
!       and set the values before first use.

	INTEGER :: MAXDES = 512 ! maximum chars in extra description string 
	CHARACTER (len=512) :: descrip ! size should match MAXDES above

	INTEGER :: MAXI = 128   ! maximum number of extra integers
	INTEGER(kind=2), dimension(128) :: iaopt   ! integer storage

END TYPE sirhead