Mammoth Mountain/Horseshoe Lake
The image on the left is of Horseshoe Lake in the center with Lake Mary in the distance to the left. It's taken from the top of Mammoth Mountain looking to the south. The picture on the right is of Mammoth Mountain taken looking to the west from the caldera floor.
The following images are part of a spectral classification of our newly acquired HyMap imagery. The first image is a subset of a much longer flightline. North is image-left. The central part of Mammoth Mountain is image center. This is a simple RGB image created from wavelengths 0.6419,0.5496,and 0.4723 microns
The subsequent images are matched filter results which is an algorithm within the ENVI suite of processing tactics that uses pure endmember spectra to map spatial occurances of said spectra. In these images, red indicates the highest degree of match while blue is the lowest degree of match.
| RGB | Alunite | Halloysite | Montmorillinite | Dv/Gyp/Mont/Bass |
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The endmembers used both in the above classifications and the ones to follow were determined through a suite of processing in ENVI. The data was both spectrally and spatially subset. The purest pixels from this processing are then analyzed by plotting them in a "n-dimensional" fashion illustrated below:
Spatially and spectrally extreme pixels clump together and suggest an endmember. Spectra of the main endmembers gleaned from this processing thus far are below:
| Full Wavelength Spectra | Spectra subset to SWIR |
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Using these endmembers, the following simple classification was done as well as the matched filter classifications presented at the beginning of the page.
| RGB | Parallelpiped Classification |
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Exhalation of CO2 from the flanks of Mammoth Mtn. has been occuring since 1989-1990. This has resulted in massive tree-kills in several locations around the mountain. The largest is located near Horseshoe Lake on the southern flank. We suggest that physiological stress in the forest communities due to the elevated gas levels can be seen in hyperspectral imagery if resolutions (both spatial and spectral) are good enough. We are attempting this analysis with the new 5-m Hymap imagery. Preliminary data follows:
| Band 109 (2.2 um) | |
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The following analysis is a simple parallelpiped classification using the endmembers gleaned from the above analysis of 2-D MNF scatter plot information. Tree-kills seem to be picked out by the regions in the image in seagreen, coral, and sienna. The red in the lakes are the shallow parts of the lake. The yellow at the bottom of the image is predominatly grassy marsh land around the Twin Lakes while the purple is water.
| Band 109 (2.2 um) | Parallelpiped Classification |
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