ETM+ Yellow/Blue Filter
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To begin fixing the brightness of the image. Select the "Land Brightness" action in the floating "Actions" tool window.
Then click the play icon at the bottom of the floating "Actions" tool window as shown in the image below.
Now we need to select all the water first with the "Magic Wand Tool", select this tool from the floating toolbar.
We need to select all the water first, because the "WaterBrightness" action cannot be played on the Land, and the "Land Color" action cannot be played on the water.
Try it if you want to see the results, but I guarantee that either one will look bad for the other. Just be prepared to undo your test action, as it will look quite bad!
Notice I have set the "Tolerance" to "20", checked "Anti-aliased", and unchecked "Contiguous". These options will need to be adjusted as you proceed with this part of this step in the tutorial. The "Tolerance" setting is quite touchy and can have a big effect on the resulting selection set, as well as how much time it takes you to finalize your selection set to just the water.
Expect to spend LOTS of time doing this!
NOTE: It is recommended that if you step away from the computer, or if you carry on with this procedure that you may want to save your selection work from time to time. To do this, skip here, then back. IMPORTANT!!! KNOW HOW TO SAVE YOUR WORK!!!!
If you are just linking here to save your selection, then return here to continue the process of refining your selection set. Recall that if you want to save your selection again, you will need to do this process again, but when you re-save the "Photoshop .psd" file, you will only need to navigate the menu control "File->Save" NOT "File->Save As..."
Click the "Magic Wand Tool" over a particular section of the ocean. Watch the behavior of the tool and the regions that are selected. This part of the process will require lots of trial and error, and it will take some time not only for you to get it right, but also for you to get the hang of it. That's why I said you should expect LOTS of time to be spent doing this.
Again you will need to adjust the "Tolerance" level of the "Magic Wand Tool", but don't spend all your time just trying out different "Tolerance" levels, and none of them will ever get it right on the first click. You will need to do additional refining of the selection set, and that takes additional time. This is again why I recommended that you KNOW HOW TO SAVE YOUR WORK!!!!
Notice that when you click over the deep ocean with the "Magic Wand Tool", the selection process can take some additional time to complete. Don't expect such advanced procedures to happen instantly, give the computer time to complete each action before proceeding. This also requires a certain level of patience. So CHILL OUT and be patient with your computer. Remember that you are working with MASSIVE images here!
Once that "Magic Wand Tool" is finally done doing its work, you will see the results of an animated selection set around some of the land, and even around some of the ocean areas. But I can almost guarantee you that there are little glitches in the selection set that you cannot see. Look at the following image, the question marks in the image show that there is nothing in that area selected. However use "Ctrl +" or "Ctrl -" on the keyboard, combined with the floating "Navigator" tool window, or the scroll bars on the bottom and right side of the image to zoom and navigate around in the image. When you have zoomed in on those question mark areas, you will see there is a great deal more problems with the selection set. Some of the selection may be over certain parts of the land, some of the selection will almost certainly be missing parts of the ocean.
Click on the image for a larger view.
Here you can see that the little glitches out in the deep ocean are still not visible, however, some of the portions of the bay south west of the island are quite visible. These are BIG problems that will need to be fixed. We will now cover the techniques to clean this up. But again expect to spend some time perfecting the selection set, and of course KNOW HOW TO SAVE YOUR WORK!!!!
Click on the image for a larger view.
Below you can clearly see that I have zoomed in enough to see just how many little errors there are in the selection set even in the deep ocean.
Click on the image for a larger view.
In the image below you can see I have tried a slightly different "Tolerance" value, and I clicked in a different area. The results are REALLY BAD!
The reason we are selecting the water first, is because it is easier to use the "Magic Wand Tool" on the reasonably uniform colors and shades in the ocean and even the reef areas, then it is to use the "Magic Wand Tool" over the decidedly un-uniform areas of the land. So this really is the best way to make this work, and I will admit it isn't that much fun, but the results are worth it!
Click on the image for a larger view.
In the image below I have further refined the "Tolerance" value, and clicked in yet another location to try and get a different result. Keep in mind that when you are zoomed in on one portion of the image, and focusing on one area of that selection, you are not able to see all the other areas of the image, and all the other areas of the selection set. So by that logic you are also not able to see all the other possible problems you are experiencing with a given selection technique. It's a good idea to take a look around the rest of the image from time to time and make sure that the other areas of your selection set in the image are also improving rather than getting worse.
Click on the image for a larger view.
Below you can again see that I have refined my technique again, this time with disastrous results. Recall that we are using the "Magic Wand Tool" over the ocean areas first because it is more uniform. Well here you can see that there are regions inland that have very close, and in some cases exactly the same color profile as the pixels out in the deep sea. Our eyes can perceive the difference, but the program cannot always have that much control as your eyes and your brain. For this reason I am open to new tools and machine vision techniques that can be imbedded within Photoshop to accomplish this process more effectively.
Remember that it is always easier to refine the selection set from the ocean, then it is from the land. That is why the example below shows that I would have a great deal of refining of the selection set to do over the land. Subtracting each of those tinny little areas over the land from the selection set would literally take me weeks. Fortunately there is another way!
Click on the image for a larger view.
Click on the image for a larger view.
Now below you can see I have a really messy selection in the deep ocean. But the land selection is quite clean. Though there are still areas in the bay that need cleaning up.
Now I have a good base selection set from which to work from. The trick to cleaning up the mess in the deep ocean is to navigate the menu control as shown in the image below "Select->Modify->Expand".
You will get the following dialog box. Set the "Expand By:" field to "2" and click the "OK" button.
You will notice that this step fully cleaned up the deep ocean, and now the only mess remaining is inland and in the bay, as well as along the shore as shown in the image below.
You will have to work to clean up these areas individually.
Hold down the "Shift" key on the keyboard, you will see a small "+" sign appear next to your "Magic Wand Tool". This means that when you click on a region that is not selected, or even that is selected, the pixel that you click on will be evaluated using the existing "Tolerance" level and run through a series of heuristics within Photoshop to determine the correct pixels to add to the current selection. It will take some time to process all the pixels in the image, but when this is done, the selection set will expand accordingly.
Hold down the "Alt" key on the keyboard, you will see a small "-" sign appear next to your "Magic Wand Tool". This means that when you click on a region that is selected, or even that is not selected, the pixel that you click on will be evaluated using the existing "Tolerance" level and run through a series of heuristics within Photoshop to determine the correct pixels to subtract from the current selection. It will take some time to process all the pixels in the image, but when this is done, the selection set will contract accordingly.
Click on the image for a larger view.
The image below shows a selection set that is a lot cleaner, however there are still areas in the bay, and on land that need to be removed or added appropriately.
You can further narrow your "Magic Wand Tool" by checking the "Contiguous" check box as shown in the image below. When you do so, be aware that it might be a good idea to increase significantly the "Tolerance" level. Again you will need to tweak the settings to get them to behave in the desired manner. MAKE SURE TO SAVE YOUR WORK!!!!
Click on the image for a larger view.
Now that the bay above is cleaned up, you need to work your way around the island and clean up any additional bays or reefs that are not included in the water selection. See the image below for an example.
Click on the image for a larger view.
Don't forget to remove any selections from the land that are not supposed to be there. In the image below you can clearly see that the dark regions in the selection set are not lakes, but rather shadows of the clouds. Make sure to remove these areas from your selection set, or the land will have far more lakes than it is supposed to, and that is only good if you are working on Minnesota the land of 10,000 lakes.
While you are looking for cloud shadows to remove, also keep you eyes open for any lakes, rivers, ponds, canals, or other waterways that may have missed the selection process.
Click on the image for a larger view.
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