
SPECTRUM(HELP)               Khoros                SPECTRUM(HELP)

     DISPLAY SUBFORM

     The "Display" subform allows you to control which map
     columns or functions of map columns are displayed as Red,
     Green, and Blue;  thus, it is primarily used with images
     that have been pre-clustered.  In addition, you may control
     whether or not values are normalized, and how they are nor-
     malized.

     1)  Control of Map Columns Displayed

     A)   An action button with which to change the map column
          displayed as Red

     A)   An action button with which to change the map column
          displayed as Green

     A)   An action button with which to change the map column
          displayed as Blue

          2)  Control of Function of Map Columns Displayed

     A)   A string selection in which to specify a function of
          map columns displayed as Red

     A)   A string selection in which to specify a function of
          map columns displayed as Green

     A)   A string selection in which to specify a function of
          map columns displayed as Blue

          3)  Control of Normalization

     A)   A logical selection with which to specify the type of
          normalization

     B)   A logical selection with which to specify when to nor-
          malize

     C)   A logical selection with which to specify how to nor-
          malize

          4) File Viewer feature

     CONTROL OF MAP COLUMNS DISPLAYED

     Pre-clustered images may have any number of map columns
     stored in the map data; which map columns are displayed as
     Red, Green, and Blue are controlled by clicking on one of
     the action buttons and selecting the desired map column from
     the list widget that will pop up.  Remember that numbering
     of map columns begins with 0.  By default, map column 0 is
     Red, map column 1 is Green, and map column 2 is blue.  For
     example, this might translate into meaning that sand is
     displayed in red, vegetation is displayed as green, and
     water is displayed as blue.  Next to the action button will
     appear a label in the form, "M#" where "M" stands for "Map
     Column" and "#" represents the number of the map column
     currently displayed as that color.

     CONTROL OF FUNCTIONS OF MAP COLUMNS DISPLAYED

     If desired, instead of specifying a map column to be
     displayed in Red, Green, or Blue, a function of map columns
     may be displayed as Red, Green, or Blue.  When specifying a
     function, you must ALWAYS use "M#" to specify the map column
     number.  Remember that numbering of map columns begins with
     0.  For example, "M3" would stand for the 4th column, and
     the specification, "M0 + M3 / M4" would indicate that you
     wanted to take each value of map column 3, divide it by the
     corresponding value in map column 4, and add the result to
     the corresponding value in map column 0.  Depending on the
     values set with normalization control, the resulting column
     of information might be normalized before display, for exam-
     ple, as red.

     NORMALIZATION

     When values in the map columns exceed the values that can be
     displayed on your screen, or when functions of map columns
     are used, normalization is often desired.  For example, a
     certain function of map columns may cause the resulting map
     column to have values from -1 to 1.  Obviously, these values
     must be normalized before they can be displayed as red,
     green, or blue.  Control of normalization provides a variety
     of possible normalization methods.  Note that "map column"
     as it is used here can apply to either a map column of the
     map data as it is displayed as Red, Green, or Blue,  or it
     can apply to the resulting column that is displayed when a
     function of map columns is used to produce a new column to
     be displayed as Red, Green, or Blue.

     Type of Normalization
          Type of normalization may be none, local, or global.
          When type of normalization is none, there is no normal-
          ization performed unless absolutely necessary;  in this
          case the user is prompted before the normalization is
          performed.  When local normalization is done, values
          are automatically normalized with respect to the larg-
          est and smallest values of a single map column;  when
          global normalization is done, values are automatically
          normalized with respect to the largest and smallest
          values of all three map columns currently displayed.

     When to Normalize
          Normalization may be done every time a map column is
          displayed, or only when it is necessary.  "Only when
          neccessary" means when the smallest value in the map
          column is less than zero, or when the largest value in
          the map column is greater than 255.

     How to Normalize
          Normalization may be done with respect to the colors
          displayable on the screen (at this time, limited to 8-
          plane), or it may be done with respect to the region
          within plus or minus 2 points of the standard devia-
          tion.

     Below is a table which helps to describe the relationship
     between when to normalize and the type of normalization.

              Normalize When Neccessary             Normalize Always
           ----------------------------------|----------------------------------
             Columns are normalized          |  Columns are normalized
             Only when values lie outside.   |  at all times.  Max & Mins used
     Local   Max & Mins used are wrt Column  |  are wrt Column in question.
             in question.                    |
                                             |
           ---------------------------------------------------------------------
             Columns are normalized          |  Columns are normalized
             when any of the entire range    |  at all times.  Max & Mins used
             of displayed values lie outside.|  are wrt all columns currently
     Global  Max & Mins used are wrt all     |  displayed.
             columns currently displayed.    |
                                             |
           ---------------------------------------------------------------------
             When automatic normalization    |
     OFF     is OFF, user is prompted to     |
             normalize only when values of   |
             column lie outside range.       |          Not Applicable
             If they say they want to normal-|
             ize, the procedure for Local    |
             normalization When Necessary    |
             is followed.                    |
           ---------------------------------------------------------------------

     THE FILE VIEWER FEATURE

     One enhancement that was suggested for spectrum was that a
     pre-defined set of equations for setting colormaps should be
     provided, such as principle component analysis, greeness
     index, and so on.  For example, in a pre-clustered image
     with six map columns, the brightness of a region might be
     defined by:
     ((M0*.3037)+(M1*.2793)+(M2*.4743)+(M3*.5585)+(M4*.5082)+(M5*.1863)).
     However, the exact equations to be provided could not be
     decided upon, and so this feature was left out for the time
     being.  As a compromise, this file viewer option was
     integrated.  Thus, if you are using pre-defined equations,
     you can bring up the ascii file in which these equations are
     defined.  Then, using the mouse buffer mechanism, you may
     yank the desired equation from the displayed file, and dump
     it directly into the string parameter box for the function
     of red, green, or blue.  (see CONTROL OF FUNCTIONS OF MAP
     COLUMNS DISPLAYED, above).

     HELP           Displays this help section.

     CLOSE          Exits the "PrintClass" subform and returns to
                    the main Spectrum form.

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

Khoros                    Release: 1.0                          1

