U.S. GEOLOGICAL SURVEY OPEN FILE REPORT 94-255


          The Southern Lake Michigan Coastal Erosion Study CD-ROM


        By  C.F. Polloni1, C.L. Brown2, D.W. Folger1, D.S. Foster1,
                             and A.L. Brill3


                  Display software by Russell A. Ambroziak4
                  Documentation by Christine A. Cook4



	1U.S. Geological Survey, Woods Hole, MA 02543
	2U.S. Forest Service, Jacksonville, OR 97530
	3Duke University, Durham, NC 27708
	4U.S. Geological Survey, Reston, VA 22092



                           How to Use VIEWLBL




         VIEWLBL is a simple image viewer which uses ASCII label
    files to describe the binary image data files.  The heart of the
    program is the label file, which is patterned after the Jet
    Propulsion Laboratory's (JPL's) 'IMDISP' ASCII label file.  For
    program VIEWLBL, each image must contain its own separate label
    file.  The simplest label file possible is a file of type '.lbl'
    containing the rows, columns, and image data file name.  The
    following is an example of a simple '.lbl' file:  (Please note:
    the examples contained within this document are for demonstration
    purposes only; the example '.lbl' files are not found on the
    OF94-255 CD-ROM.  The '.lbl' files contained on the disc are
    patterned after the following examples and can be viewed with the
    DOS 'type' command.)
    
         IMAGE_LINES    = 2057
         LINE_SAMPLES   = 1435
         IMAGE_POINTER  = PD356001.dat
    
         This will tell VIEWLBL to view the file 'PD356001.dat'. 
    This '.lbl' file tells VIEWLBL that the image has 2057 lines and
    that each line contains 1435 pixels (picture elements).  The
    image is assumed to be a gray-scale image with no color palette
    file.  Each pixel will be one byte in size and there is no header
    in the image data file.  There are a number of varieties to the
    above '.lbl' file, some of which appear on the OF94-255 disc.
    
         In order for VIEWLBL to function properly, the label,
    palette, and binary data files for the image should be located in
    the same directory.  After typing 'viewlbl' at the DOS prompt,
    you will see a list of available '.lbl' files appear on the right
    side of the screen along with the following instructions:
    
         Use up and down arrow keys, PgUp or 
         PgDn, or type the filename to position
         highlighted cursor.  Hit 'Enter' to   
         select the file or 'Esc' to leave this
         menu.                                   
           
    
    Move the highlight bar over the image you wish to view, and
    hit <Enter> or the left mouse button.  You will then see the
    image displayed.  Next, you will see a box appear in the upper 
    right corner of the screen.  This is the zoom box and can be
    manipulated with the above instructions.  If you wish to zoom,
    hit <Enter>; if you do not wish to zoom, hit <Esc>.  Note: the
    mouse is inactive while in the zoom function.  You will then see
    the following list of options at the top of the screen:
    
         System        Zoom        Analyze        Plot        Quit
         ------        ----        -------        ----        ----
         color                     pixel info     boundary     
         targa file                histogram      labels .grf
         hide  menu                shade          caption
                                   smooth
                                   rescale
    
    The following describes the functions:
    
    System
    ------
    color
    The following functions alter the color of the image.
    
         change +/-,789,123:
         This allows you to change the color image as a whole.  '+'
         increases the intensity and '-' decreases it.  The number   
         pad controls the hues.  It is operated as follows:
            Red         Green         Blue
            ---         -----         ----
             7            8             9    increases the hue value
             1            2             3    decreases the hue value
              
    
         stretch RGB:
         If the color image does not use the full range of intensity 
         in its color palette, you can stretch the colors.  The      
         option will have no effect on gray-tone images.  There is no
    
         change in the hues or saturations of the colors.  Only      
         intensities are changed.
    
         reset:
         This will set the palette back to the original.     
    
         change one color:
         If you wish one color on your image to be different, this   
         function allows you to change that one color without        
         changing any of the other colors.
    
         save new table:
         After you have altered the image colors, you can save the   
         new palette information in place of the old information.  It
         is a good idea to save a copy of the old palette file first 
         before using this option.  To save the old palette to a     
         backup file, you must exit from VIEWLBL.
    
         exit color:
         This allows you to exit the color functions and returns you 
         to the main SYSTEM menu.
    
    
    targa file:
    This allows you to output a 32-bit targa file of the image you
    are working with.
    
    hide menu:
    This will hide the menu.  Hit <Esc> or the right mouse button to
    see the menu again.
    
    
    Zoom
    ----
    If the image is too large to fit on the screen, a subsampled
    image is displayed.  This function allows a selected area of the
    sampled image to be viewed at full resolution.  If the full-
    resolution image will fit on the screen, then this option is
    inoperative.  A box appears on the image which represents the
    size and shape of a full-resolution (every pixel) sample of the
    image.  The box can be moved 16 pixels at a time in any direction
    by using the arrow keys.  To change the distance the box moves
    each time, use '+' and '-' keys to double and halve this value,
    respectively.  The size (not the shape) of this box can be
    changed by using 'l' for larger and 's' for smaller.  Hit <Enter>
    to select a portion of the image or <esc> to exit without
    changing the display.  Note, if the zoom box is  made to be
    smaller than full-resolution, the box will change color.  Beware
    of zooming in too far and thus causing replication of pixels to
    occur. 
    
    
    
    Analyze
    -------
    pixel info:
    This puts a cursor in the middle of the screen which can be moved
    to get pixel information.  The cursor is moved with the arrow or
    number pad ('Num Lock' = off), and the amount of movement is con-
    trolled with '+' and '-'.  The display at the bottom will change
    with available information but it will look something like this:
    
        x=256 y=416  84  r: 57 g: 31 b: 26
        3520  5120 lat =  47.76468 lon = -126.63266
    
    Not all images will have all of the above information.  Some will
    only give x and y locations.  In this example, the cursor on the
    screen is at pixel (256,416) which is pixel (3520,5120) in the
    image file.  The value of the pixel on the screen is 84, while
    the values of the red, green, and blue pixels used to make the
    color image are 57, 31 and 26, respectively.  These RGB values
    come directly from the files used to make the composite image and
    are not scaled in any way.
    
    histogram:
    This does a histogram of the screen data by data number (dn). 
    The first choice is a box that asks where you want the graph. 
    Use the following to position the histogram box:
    
            (l)arger
            (s)maller
            (H)igher
            (S)horter
            (W)ider
            (N)arrower
            '+' move more
            '-' move less
    
    Do not cover data with this box as it will be destroyed (on the
    screen only, not in the file.)  When you are satisfied with the
    position of the histogram box, hit <Enter>.  After <Enter> is
    hit, any information existing under the box will be blanked
    out.  Next, a smaller box appears on the screen.  This box is
    also operated by the commands above.  After you have sized this
    box, hit <Enter>; the histogram of information contained within
    this box is then graphed in the area determined by the first box
    placement.  To end this function, hit <Esc>.
    
    shade:
    Makes a shaded-relief of the image with the light source to the
    right.  This function asks for the contrast value (between 1 and
    20).  Trial and error will determine which is best; start with a
    contrast of 10 and work from there.
    
    smooth:
    Does a 3x3 average of the pixels.  Use this before 'Shade'.
    
    rescale:
    This rescales the image to fit on the screen.
    
    
    Plot
    ----
    boundary plot:
    If a vector section exists within the image .LBL file, this
    function allows you to plot those vectors.  After you have called
    this function, a menu will appear on the right side of the
    screen with the vector sets listed.  Move the highlight bar over
    the linework you want and hit <Enter>.  You will see the vectors
    plotted over the image.  After they have finished plotting, the
    menu of vector sets will return. Either plot more linework, or
    exit this function to return to the main menu.
    
    labels .grf:
    This will plot point information found within a '.grf' file.
    
    caption:
    If a caption section exists within your image '.lbl' file, this
    option allows you to plot the caption.  The caption will automat-
    ically plot on the subsampled image, but if you have zoomed into
    a section of the image, then the caption will not automatically
    plot; you have to call it up.  After you have selected the
    caption function, you will see the caption plot in the lower
    right corner of the screen.
    
    
    Quit
    ----
    This will return you to the list of all '.lbl' files.  If you hit
    <Esc> a couple of times, you will return to the DOS prompt.