
elasinfo(1)                  Khoros                   elasinfo(1)

PROGRAM
     elasinfo - Reads and prints an ELAS file format header.

SYNTAX
     elasinfo

     -i             input ELAS data file

     [-f]           output ascii file

     [-V]           Gives the version for elasinfo

     [-U]           Gives the usage for elasinfo

     [-P]           Prompts for command line options

     [-A [file1]]   Creates the answer file called elasinfo.ans
                    or file1

     [-a [file1]]   Uses elasinfo.ans or file1 as the answer file

DESCRIPTION
     elasinfo is a routine that reads and prints an ELAS image
     file format header.  The ELAS image file format describes
     the image format used by the ELAS Image system.

     Record 1 contains all the header information. The remaining
     records, beginning with record 2 store image data one scan-
     line at a time in (BIL) band-interleaved-by-line format for
     any number of bands. Each record contains one scan line of
     one channel, thus each record corresponds to a new scan line
     for a particular channel.

     The Band-Interleaved-By-Line order means that the first
     scanline of the first band is stored first. It is followed
     by the first scanline of the second band, third band, fourth
     band, and so on up to the last band avaliable. This order
     then repeats for the second scanline, the third scanline and
     so on.

     The format is according to the following scheme:

          Record Number         Data Description
          ------------          ----------------
                1               Header Record
                2               Scan line 1, channel 1
                3               Scan line 1, channel 2
                4               Scan line 1, channel 3
                5               Scan line 2, channel 1
                6               Scan line 2, channel 2
                .                        .
                .                        .
                .                        .

     Note that the terminology for band and channel is used
     interchangably, The term band is typically used in the con-
     ventional image processing community, while channel is com-
     monly used in the remote sensing community.  Scan line here
     refers to one row of the image.

     The image header for the ELAS image file format is as fol-
     lows:

      BYTES      TYPE                DESCRIPTION
     -------     ----    -------------------------------------------
     [1-4]       int     (NBIH) Number of bytes in header.
     [5-8]       int     (NBPR) Number of bytes per record.
     [9-12]      int     (IL)   Initial line of data file.
     [13-16]     int     (LL)   Last line of data file.
     [17-20]     int     (IE)   Initial element of each scan line.
     [21-24]     int     (LE)   Last element of each scan line.
     [25-28]     int     (NC)   Number of channels (bands).
     [29-32]     int     (4321) Header record identification.
     [33-36]     ASCII   Grid descriptor for Y-axis: NOR, LSNL, etc.
     [37-40]     int     Y-Offset: Y-coordinate value for scan line 0.
     [41-44]     ASCII   Grid descriptor for X-axis: EAS, LNSE, etc.
     [45-48]     int     X-Offset: X-coordinate value for element 0.
     [49-52]     float   Y Spot size, or pixel element height.
     [53-56]     float   X Spot size, or pixel element width.
     [57-72]     float   Transformation matrix (linear) from line and
                          column (IL, LL, IE, LE) coordinates to the
                          coordinates described by the grid descriptors.
                            1., 0., 0., 1. =  identity transformation
                            1., 0., 0., -1. = data in UTM format
     [73-84]     ---     Not Used.
     [85-88]     int     (Eikonix) Used by modules RFEKDA and VEKS.
     [89-92]     int     (LABL) Used by module LABL.
     [93-96]     ASCII   (HEAD) Used by module HEAD.
     [97-480]    ASCII   Comments - 6 lines at 64 characters each or
                          96 4-character descriptiors for data base use.
     [481-992]   int     Color Table (color map)
     [993-1024]  ---     Not Used.

     IMPORTANT

     The utilities used to read and write the ELAS image file are
     machine dependent.  WE ASSUME THAT THE ELAS IMAGE WILL
     ALWAYS BE IN LITENDIAN BYTE FORMAT.  This means that a
     machine that uses bigendian byte order (i.e. sun, sony, etc)
     must byte swap some fields in the image header. So, the code
     allows conversion between litendian byte order and bigendian
     byte order.

     The only file that has machine dependencies is elas.c in the
     file_formats library (libfile_formats.a).

     1. The not define flag
               This routine can be compiled so that it is not
               machine dependent by using -DNMD option. NMD
               stands for not machine dependent.  When compiled
               with this option the bigendian to litendian
               conversion is not performed.

     2. defines for machine dependencies
               The defines for machine dependencies (conversion
               to and from bigendian) are sun, bigendian, and
               ieeeorder. So elas.c can be compiled with -Dbigen-
               dian. Note, when compiling on a sun machine, sun
               is defined so the conversion code from bigendian
               to litendian will be be compiled. If it is
               unwanted see 1. above.

REQUIRED ARGUMENTS
     -i     type: infile
            desc: input ELAS data file

OPTIONAL ARGUMENTS
     -f     type: outfile
            desc: output ascii file

EXAMPLES
     elasinfo -i image.elas -f image.info

     This will read an image in the ELAS image file format and
     print out the header information to the specified file in
     ASCII format.

     elasinfo -i image.elas -f #

     This will read an image in the ELAS image file format and
     print out the header information to the standard output dev-
     ice.

SEE ALSO
     intro(1), verror(3), vgparms(3), vutils(3), lelasinfo(3)

RESTRICTIONS
COPYRIGHT
     Copyright 1991, University of New Mexico.  All rights
     reserved.

Khoros                    Release: 1.0                          1

