
SPECTRUM(HELP)               Khoros                SPECTRUM(HELP)

     SCATTER PLOT SUBFORM

     The "Scatter Plot" subform allows you to create a 2D scatter
     plot of the columns of map information associated with pre-
     clustered data.  You may zoom in on the plot for greater
     accuracy;  you may also use the scatter plot in either its
     normal or zoomed forms to add or delete clusters from a
     selected class category.   The scatter plot displayed may be
     proportional or non-proportional.

     When the scatter plot is displayed, every cluster in the map
     columns will be plotted;  however, some points may overlap
     others -- it may be necessary to use the "Zoom" option to
     see all the points.  The scatter plot will be presented in
     different colors; unassigned clusters will appear in white,
     while assigned clusters will appear in the same color that
     was specified for their associated class category on the
     Legend subform.

     An additional feature of the scatter plot is the "roving"
     highlighted point.  This feature highlights the point on the
     scatter plot that represents the cluster located directly
     under the cursor when the cursor is in the image window.  It
     is sometimes difficult to see;  look closely to see the rov-
     ing orange point.

     1)   Control of Map Columns Displayed

     2)   Control of Function of Map Columns Displayed

     3)   Zoom Control

     4)   Adding & Deleting Clusters with the Scatter Plot

     5)   Control of Proportional/Non-Proportional Plotting

     CONTROL OF MAP COLUMNS DISPLAYED

     A pair of action buttons are provided, with which you may
     specify which columns of map information are displayed as
     the X and Y coordinates of the points in the plot.  Pre-
     clustered images may have any number of map columns stored
     in the map data; which map columns are displayed as the X
     and Y coordinates of the scatter plot 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, the X coordinates come from map column 0 and Y
     coordinates come from map column 1.  For example, this might
     translate into meaning that X coordinates provide an indica-
     tion of vegetation, and Y coordinates provide an indication
     of moisture.  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 X or Y.

     CONTROL OF FUNCTIONS OF MAP COLUMNS DISPLAYED

     A pair of string selections are available, with which you
     may specify any desired function of the columns of map
     information which will be displayed as the X and Y coordi-
     nates of the points in the plot.  If desired, instead of
     selecting a map column to be displayed as the X or Y coordi-
     nates of the scatter plot, a function of map columns may be
     displayed as the X or Y coordinates.  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 actually 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.  Accord-
     ing to how the Normalization Control is set on the "Display"
     subform, the resulting column of information might be nor-
     malized before display, for example, as the X coordinates of
     the plot.

     ZOOM CONTROL

     On the Scatter Plot subform is a float selection in which to
     enter the desired zoom factor, and a button labelled "Set
     Zoom" with which to initiate the zooming action.  After the
     zooming action has taken place, this button will change its
     name to "Reset", as you use the same button to reset the
     plot to its original appearance with a zoom factor of 1.

     To zoom in on the plot, enter the desired zoom factor in the
     Zoom Factor parameter box, and hit <cr>.  This will set the
     zoom factor;  the region to be zoomed in on will appear in a
     white box.  Note that the white zoom box will NOT appear
     until you hit <cr>.  Now, you may move the zoom box about by
     clicking on a point in the plot.  Note that you must click
     exactly on a point in the plot in order to make the zoom box
     move to that location.  When you have the zoom box located
     at the area of interest, click on the "Set Zoom" button. The
     region that previously appeared inside the white box will be
     expanded to fill the entire plot area.  Add and/or delete
     clusters from class categories as desired within the zoom
     window, using the "Select Current Class" button to specify
     which class category is being added to or deleted from.
     When you are finished, click on the "Reset" button  (notice
     that the same button functions both as "Set Zoom" and
     "Reset").  The original plot will be re-displayed, the white
     box appearing over the region that was just zoomed on.  You
     may repeat this process as desired.

     ADDING & DELETING CLUSTERS FROM A CLASS USING THE SCATTER
     PLOT

     There is an action button labelled, "Select Current Class";
     when this button is click on, a list widget will come up,
     from which you may select the current class category to
     which you may add or delete clusters.  A logical button
     labelled, "Operation" allows you may switch from "Add Clus-
     ters" to "Delete Clusters", depending on whether you wish to
     add or delete clusters from the current class category.

     First, use the "Select Current Class" button to select the
     class category in which you are interested.  Second, toggle
     the "Operation" button to "Add Clusters" or "Delete Clus-
     ters", depending on which operation you want to perform.
     Now, move the cursor into the plot window.  Holding the but-
     ton down, move the cursor over the points representing the
     clusters that you wish to add/delete from the class
     category.  Release the mouse button when you are finished
     with the operation.

     CONTROL OF PROPORTIONAL/NON-PROPORTIONAL PLOTTING

     There is a logical selection with which you may specify:
     "Proportional Plotting:"  as "True" or "False".  The default
     is True.  A proportional scatter plot means that the minimum
     and maximum values across both the map columns (functions of
     map columns) being displayed as X and Y are found before the
     plot is displayed.  Then, the lower left corner of the plot
     window is set to the minimum; the upper right corner of the
     plot window is set to the maximum.  This is proportional
     plotting;  the range of numbers covered by the X and Y axes
     are the same.  The "sense of proportion" conveyed by the
     plot is correct, but details of the plot may be lost if the
     range spanned by X varies greatly from that spanned by Y.

     In some cases, proportional plotting may be an inconvenient
     method of display.  For example, suppose the data displayed
     as X ranges from 0 to 255, but the data displayed as Y
     ranges from 0 to 1.  Obviously, the plot will not be very
     informative, as all the points will be bunched against the X
     axis.  In cases like this, non-proportional plotting may be
     more useful.  In non- proportional plotting, the x minimum
     value of the plot window is set to the the minimum value in
     the data represented as X, and the y minimum value of the
     plot window is set to the minimum value in the data
     represented as Y.  Thus, the plot window is not propor-
     tional;  X values may cover a range that is significantly
     larger or smaller than that covered by Y values.  While the
     "sense of proportion" conveyed by the plot is incorrect,
     details of the plot are correctly preserved even when the
     range spanned by X varies greatly from that spanned by Y.

     Information Displayed in the Position Widget

     When you move the cursor over a point displayed in the
     scatter plot, its (x, y) coordinates will be displayed in
     the position widget.

     HELP           Displays this help section.

     CLOSE          Exits the "Legend" subform and returns to the
                    main Spectrum subform.

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

Khoros                    Release: 1.0                          1

