This week's lab continued with ERDAS Imagine to add various filters to raster imagery data, as well as editing the band color combinations. Available filters that can be applied include high pass, low pass, mean, range, etc. Each filter produces different variation to the photo and can be useful to highlight certain features in an image. For example, the high pass filter created a photo with more detail and more defined edges, while the low pass filter created an image with softer, smoother edges. Band combinations can also be changed. For the images above, we were given clues on what pixel values to look for when identifying an unknown feature. The first feature was a river with had pixel values between 12 and 18 on layer 4 and I chose to use a band combo of 4, 2, 1 which made the forested areas appear red and the water appear black. The second feature was the snow capped mountains. A band combo of 5, 4, 3 showed the snow as bright blue and the forested areas as a bright green. The Inquiry tool was used to test points on the image to find a feature that matched the description. The final feature was the shallow area of the river, which was best highlighted by the 4, 3, 2 band combo.
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