12.4 GUI - Modifying Image and Graphics Colors
Modifying Image Colors
In this exercise, you will display an image over Europe, restore the default
enhancement, and modify the image and graphics colors.
- Display a Meteosat image and map on the current frame, using data from
band 8 of the MET/B dataset.
- In the Display/Image GUI, select: the MET/B dataset, band 8,
and to display a map on the image.
- Select one image from the image list, load the image, and dismiss the
Image Select window.
- Obviously, these colors are not the colors of a normal water vapor image.
Even though the frames were erased, the NEXRAD enhancement is still assigned to that frame.
So, you'll need to restore the correct colors by modifying the Image Colors.
- Select: Colors/Change Image Colors
- Click: the Reset tab
The default option in the Reset tab is to reset the current frame only.
- Click: Reset
- Activate the GUI where you'll create your own enhancement.
- Click: Make
The Make tab of the Image Colors GUI contains four options in which you can
change or create image colors:
'Using Color Names,' 'Using Color Intensities,' 'Using ENH,' and 'Using EB.'
- The 'Using Color Names' button consists of two scroll bars labeled
'Begin' and 'End.' The scroll bars allow you to select a beginning and ending color
from one of the
35 predefined McIDAS colors.
- The 'Using Color Intensities' button also has the two scroll bars, but allows you
to choose the exact amount of red, green,
and blue intensities to create your own colors.
- The 'Using ENH' button is a graphical way to change the intensities of red, green,
and blue.
- The 'Using EB' button starts the EB command which invokes the interactive
mouse-controlled contrast stretching. Press the right mouse button to end the
process, leaving the current enhancement.
Start out by using the predefined McIDAS colors.
- Click: Using Color Names
- Use the predefined color 'Firebrick' to begin at a grayscale of 100, and 'Gold'
to end at a grayscale of 150.
- Slide: the Begin scrollbar to 100.
- Slide: the End scrollbar to 150.
- Select: Beginning Color/Firebrick
- Select: Ending Color/Gold
- Click: Apply Enhancement
Look at the Image window. You should see that all brightness values from 100 to 150
are colored from Firebrick to Gold, depending on the specific value. All other
brightness values will remain in their original grayscale form.
- Repeat Step 4 several times, changing the colors and input values each time.
- Once you have finished altering the image colors, dismiss the color selection GUI and
save the enhancement as LEARNING.ET.
- Click: Dismiss
- Click: Save
- Type: LEARNING
- Click: Save
- Reset the original image enhancement and restore LEARNING.ET to the image once again.
- Click: Restore
- Select: Select Enhancement File/LEARNING.ET
- Click: Restore
- Restore the original image enhancement.
- Click: Reset
- Select: Frame Selection/Set for Current Loop
- Click: Reset
- Click: Dismiss
Modifying Graphics Colors
- Change the color of the map in frame 4.
- Select: Colors/Change Graphic Colors
- Click: Create a New Color
- Slide: the Red, Green, and Blue Intensity bars until you've created a color you like.
- Click: Apply Enhancement
- Click: Dismiss
Look at the image window, and you will notice the changes to graphic color
1 took effect immediately.
- Save the new graphics table as LEARNING.GRX.
- Click: Save
- Type: LEARNING in the File Name field
- Click: Save
- Restore the default graphics colors.
- Click: Reset
- Select: Frame Selection/Current Frame Only
- Click: Reset
- Close the Graphics Colors window.
- Click: Dismiss