In this exercise, you will use the EU command to assign colors to brightness values. You will create a simple enhancement that assigns brightness values to colors and another enhancement that assigns various brightness ranges to color ranges.

1. Start a McIDAS session.

   At the Unix prompt:

   Type: mcidas

   Your session should still be set for six frames from the last time you edited your .mcidasrc file. If not, set it for six frames, as described in Getting Started.

2. Log on and initialize the workstation.

   Type: LOGON   initials   project#   I

3. Set the loop sequence to frames 1 through 6.

   Type: LS 1-6

4. Display the first GOES-7 4km IR image on frame 1 centered on New Orleans. Decrease the image resolution by a factor of 2 and place a grayscale bar on the frame.

   Type: IMGDISP GI4.1 1 STA=NEW MAG=-2 SF=YES;BAR LINT=10

5. Assign the color red to the brightness range 180 to 220 to color enhance the cloud tops.

   Type: EU MAKE 180 220 RED

   Notice how the grayscale bar also changes to reflect the changes to the enhancement.

6. List the enhancement table. The brightness values between 180 and 220 are assigned to a red intensity range of 255 to 255.

   Type: EU TABLE

    Brightness  Blue      Green      Red                                           
     min max   min max   min max   min max                                         
     --- ---   --- ---   --- ---   --- ---                                         
       0 179     0 179     0 179     0 179                                         
     180 220     0   0     0   0   255 255                                         
     221 255   221 255   221 255   221 255                                         
   

7. Assign the brightness range 180 to 220 to the range of colors between yellow and red.

   Type: EU MAKE 180 220 YELLOW RED

   The brightness value 180 is yellow, the brightness value 220 is red, and the values in between are displayed as various shades between the two colors.

8. List the enhancement table.

   Type: EU TABLE

   The enhancement table is listed as shown below. The blue, green, and red intensity values of 0, 255, and 255 create the color yellow and are assigned to brightness value 180. The blue, green, and red intensity values of 0, 0, and 255 create the color red and are assigned to brightness value 220.

    Brightness  Blue      Green      Red                                      
     min max   min max   min max   min max                                    
     --- ---   --- ---   --- ---   --- ---                                    
       0 179     0 179     0 179     0 179                                    
     180 220     0   0   255   0   255 255                                    
     221 255   221 255   221 255   221 255                                    
   

9. Save the enhancements with the name STORM.

   Type: EU SAVE STORM

10. Restore the default enhancement to the frame.

    Type: EU REST

11. Restore the enhancement STORM to the frame.

    Type: EU REST STORM

12. List the enhancement tables in your account on the workstation.

    Type: EU LIST

    The file STORM.ET should be listed.

13. Delete the enhancement STORM.

    Type: EU DEL STORM

14. Restore the default enhancement to frames 1 through 6.

    Type: EU REST X 1 6

    The X after the REST parameter indicates to use the default enhancement.

15. Erase the image and the graphics from frame 1.

    Type: ERASE