User Manual - pancroma

Note that the band 6 (TIR) track bar is not set. This must be done manually.Reading Data from NASA JPL ASCII Spectra FilesNASA/JPL also publishes ASCII spectral libraries, found athttp://speclib.jpl.nasa.gov/ . These are more comprehensive than the USGSlibraries as they offer spectra for the visible, VNIR, SWIR and TIR spectralranges. You must inspect the XStart and XStop limits carefully in order todetermine the range of wavelengths included in a particular file. If the targetwavelengths are not in the file you will obviously not get a match.In order to read one of these ASCII files, select ‘File’ | ‘Open’ and open the file.Next, select ‘Spectral Analysis’ | ‘Read Spectrum from ASTER ASCII File’. Thesubmenus will specify your target wavelengths as described above for the USGSspectral files.Landsat Linear Spectral UnmixingSpectral unmixing represents an interesting approach to understanding andusing multispectral data. The method starts with an assumption that thecharacteristics of observed image pixels constitute mixtures of the characteristicsof a small number of basic cover types, called endmembers. If the mixtures areassumed to consist of linear combinations of the contributions of the individual266