User's Guide

TRANSLAS5

Copy and convert an image to LAS 5.0 format.

Function:

Converts a LAS 6.0 or newer image into a LAS 5.0 image.

Parameters:

IN
Input image. A LAS 6.0 or newer image to be converted. The name of the image is given in LAS file naming conventions.

OUT
Output image. The ouput image will be in the LAS 5.0 format.

ODTYPE(SAME)
Output data type. The data type of the output image. TRANSLAS5 truncates when converting from a higher (REAL*4) to lower (BYTE) data type. The MAP module should be used to rescale images.

  = SAME:   Same as first input image data type
  = BYTE:   BYTE
  = I*2:    INTEGER*2
  = I*4:    INTEGER*4
  = R*4:    REAL*4

COMPFLG(-- )
Compression flag. Flag indicating if the output image should be compressed or not.

  = YES:    The output image will be compressed.
  = NO:     The output image will not be compresed.
  = --:     Compression will be based on the TAE global $COMPFLG. If 
            $COMPFLG is not specified as YES or NO, compression will
            be based on the unix environment variable $COMPRES. This
            variable must be set to ON for compression to take
            place.

Examples:

  1. LAS> translas5 in=ny.dat out=out.dat

    NY.DAT;IMG is converted into a LAS 5.0 image, OUT.DAT;IMG. OUT.DAT;IMG has the same number of lines, number of samples, and data type as NY.DAT;IMG because window and band options were not specified and ODTYPE is SAME by default.

  2. LAS> translas5 in="image1(:1,3) + image2(100,200,500,512:4)" out=out.dat odtype=i*4

    Bands 1 and 3 of IMAGE1;img and band 4 of IMAGE2;img will be combined and converted to a LAS 5.0 image, OUT.DAT;img. It is assumed that IMAGE1;img is a 500 line by 512 sample image; otherwise, an error would result because the window sizes are not the same. Image OUT.DAT;img is a LAS 5.0 image consisting of a three-band, 500 line by 512 sample image with a data type of 32-bit signed integer.

Description/Algorithm:

Error checking is done on the input image(s) to ensure that they all have equal window sizes. The input image is then converted into a LAS 5.0 format. This is done by reading in an image with LAS 6.0 I/O support routines and writing it out with LAS 5.0 I/O support routines.

Nonfatal Error Messages:

    None.

Fatal Error Messages:

  1. [translas5-fatal] Fatal error encountered

    A fatal error was encountered during processing. Processing is terminated. The error message that is displayed immediately preceding this message is the specific error that was encountered.

  2. [translas5-window] Input images do not have the same window sizes

    Error occurs if multiple input images are specified with different window sizes.

User Notes:

  1. When subwindowing an image, the output image origin is reset to (1,1).

  2. TRANSLAS5 may also be used to combine several separate LAS images into a single LAS 5.0 image.

  3. Some images may not compress and may actually expand when the COMPFLG is set to YES. Some example images that do this are created by TESTGEN-RAN. Images that expand generally contain a random dispersion of most of the possible intensities.

  4. A LAS 5.0 image is placed in band sequential order. Each line of the image is padded so that each line completely fills a discrete number of 512 byte blocks. There is also a 512 byte header block with descriptive information. The last line is not padded.

  5. A LAS 6.0 image is placed in band sequential order with no padding. There is no header block either.

  6. TRANSLAS5 generates image files compatible with older software such as CALPLOT.