WELCOME TO THE GLOBE DEMO

   The globe demo illustrates a number of features of
   the IDL language, including texture mapping, model
   rotations, and the concept of a color palette.

   The globe demo illustrates texture mapping,
   a method of warping images to polygons. The 
   polygons in this demo make up the Earth. Specifically,
   the datasets are texture mapped onto a sphere object.
   You can change the texture map that is displayed over 
   the continents or over the oceans.

   You can also rotate the globe interactively. Position
   the cursor on the image and, while holding down the 
   left mouse button, move the cursor to rotate the 
   globe. Release the mouse button when you are 
   satisfied with the position of the globe. This 
   functionality is new to IDL 5.0 and uses IDL's new 
   object graphics. The Trackball object is used for the 
   Globe Demo.

   The globe demo also illustrates the concept of
   a color palette.  A color palette is a color lookup 
   table used to map values (of an image) to red, green, 
   and blue intensities. Temperatures are displayed with 
   colors that range from red to blue and topography is 
   displayed in grayscale.  The color palette is divided 
   so that one dataset uses one portion of the color
   palette and another dataset uses another portion of
   the color palette.

   You can also "stretch" the color palette within the
   globe demo, which alters only the color palette; 
   image values remain constant. A stretch remaps the 
   red, green, and blue values to new image values. For
   instance, the red to blue portion of the color
   palette is mapped to the temperature values. You
   can shift the color palette associated with
   temperatures so that red is mapped to lower 
   temperatures.  The entire color palette is stretched 
   with this shift.  Conversely, one may shift the color 
   palette so that blue is mapped to higher 
   temperatures. Shifting the color palette can 
   accentuate image features. In this demo, you can 
   emphasize regional variability in temperature or 
   topography.


   MENU OPTIONS
   ------------

   File Menu:
      Select "Quit" to exit the Globe Demo and return to
      the IDL Demo main screen.

   Options Menu:
      Select "Reset Orientation" to return to the initial
      globe perspective. 
 
   Help Menu:
      Select "About the Globe Demo" for information about 
      the Globe Demo.


   FEATURES
   --------

   <<Continents:Temperature/Topography>> radio button
      Displays either temperatures or topography over 
      the continents.
 
   <<Oceans:Temperature/Topography>> radio button
      Displays either temperatures or topography over
      the oceans.

   <<Stretch temperature minimum>> slider
       Stretches the temperature color palette; the
       color associated with the minimum temperature
       is shifted to a higher temperature. The entire
       temperature palette is stretched.
 
   <<Stretch temperature maximum>> slider
       Stretches the temperature color palette; the
       color associated with the maximum temperature
       is shifted to a lower temperature. The entire
       temperature palette is stretched.
 
    <<Stretch topography minimum>> slider
       Stretches the topography color palette; the
       color associated with the minimum elevation
       is shifted to a higher elevation. The entire
       topography palette is stretched.
 
    <<Stretch topography maximum>>
       Stretches the topography color palette; the
       color associated with the maximum elevation
       is shifted to a lower elevation. The entire
       topography palette is stretched.