USGS Spectral Library Version 7 Data

This data release provides the U.S. Geological Survey (USGS) Spectral Library Version 7 and all related documents. The library contains spectra measured with laboratory, field, and airborne spectrometers. The instruments used cover wavelengths from the ultraviolet to the far infrared (0.2 to 200 microns). Laboratory samples of specific minerals, plants, chemical compounds, and man-made materials were measured. In many cases, samples were purified, so that unique spectral features of a material can be related to its chemical structure. These spectro-chemical links are important for interpreting remotely sensed data collected in the field or from an aircraft or spacecraft. This library also contains physically-constructed as well as mathematically-computed mixtures. Measurements of rocks, soils, and natural mixtures of minerals have also been made with laboratory and field spectrometers. Spectra of plant components and vegetation plots, comprising many plant types and species with varying backgrounds, are also in this library. Measurements by airborne spectrometers are included for forested vegetation plots, in which the trees are too tall for measurement by a field spectrometer.  
The related U.S. Geological Survey Data Series publication, "USGS Spectral Library Version 7", describes the instruments used, metadata descriptions of spectra and samples, and possible artifacts in the spectral measurements (Kokaly and others, 2017).  
Four different spectrometer types were used to measure spectra in the library: (1) Beckman™ 5270 covering the spectral range 0.2 to 3 µm, (2) standard, high resolution (hi-res), and high-resolution Next Generation (hi-resNG) models of ASD field portable spectrometers covering the range from 0.35 to 2.5 µm, (3) Nicolet™ Fourier Transform Infra-Red (FTIR) interferometer spectrometers covering the range from about 1.12 to 216 µm, and (4) the NASA Airborne Visible/Infra-Red Imaging Spectrometer AVIRIS, covering the range 0.37 to 2.5 µm.  
Two fundamental spectrometer characteristics significant for interpreting and utilizing spectral measurements are sampling position (the wavelength position of each spectrometer channel) and bandpass (a parameter describing the wavelength interval over which each channel in a spectrometer is sensitive). Bandpass is typically reported as the Full Width at Half Maximum (FWHM) response at each channel (in wavelength units, for example nm or micron). The linked publication (Kokaly and others, 2017), includes a comparison plot of the various spectrometers used to measure the data in this release. Data for the sampling positions and the bandpass values (for each channel in the spectrometers) are included in this data release. These data are in the SPECPR files, as separate data records, and in the American Standard Code for Information Interchange (ASCII) text files, as separate files for wavelength and bandpass. 
Spectra are provided in files of ASCII text format (files with a .txt file extension). In the ASCII files, deleted channels (bad bands) are indicated by a value of -1.23e34. Metadata descriptions of samples, field areas, spectral measurements, and results from supporting material analyses – such as XRD – are provided in HyperText Markup Language HTML formatted ASCII text files (files with .html file extension). In addition, Graphics Interchange Format (GIF) images of plots of spectra are provided. For each spectrum a plot with wavelength in microns on the x-axis is provided. For spectra measured on the Nicolet spectrometer, an additional GIF image with wavenumber on the x-axis is provided.  
Data are also provided in SPECtrum Processing Routines (SPECPR) format (Clark, 1993) which packages spectra and associated metadata descriptions into a single file (see the linked publication, Kokaly and others, 2017, for additional details on the SPECPR format and freely-available software than can be used to read files in SPECPR format). 
The data measured on the source spectrometers are denoted by the “splib07a” tag in filenames. In addition to providing the original measurements, the spectra have been convolved and resampled to different spectrometer and multispectral sensor characteristics. The following list specifies the identifying tag for the measured and convolved libraries and gives brief descriptions of the sensors. 
splib07a – this is the name of the SPECPR file containing the spectra measured on the Beckman, ASD, Nicolet and AVIRIS spectrometers. The data are provided with their original sampling positions (wavelengths) and bandpass values. The prefix “splib07a_” is at the beginning of the ASCII and GIF files pertaining to the measured spectra. 
splib07b – this is the name of the SPECPR file containing a modified version of the original measurements. The results from using spectral convolution to convert measurements to other spectrometer characteristics can be improved by oversampling (increasing sample density). Thus, splib07b is an oversampled version of the library, computed using simple cubic-spline interpolation to produce spectra with fine sampling interval (therefore a higher number of channels) for Beckman and AVIRIS measurements. The spectra in this version of the library are the data used to create the convolved and resampled versions of the library. The prefix “splib07b_” is at the beginning of the ASCII and GIF files pertaining to the oversampled spectra. 
s07_ASD – this is the name of the SPECPR file containing the spectral library measurements convolved to standard resolution ASD full range spectrometer characteristics. The standard reported wavelengths of the ASD spectrometers used by the USGS were used (2151 channels with wavelength positions starting at 350 nm and increasing in 1 nm increments). The bandpass values of each channel were determined by comparing measurements of reference materials made on ASD spectrometers in comparison to measurements made of the same materials on higher resolution spectrometers (the procedure is described in Kokaly, 2011, and discussed in Kokaly and Skidmore, 2015, and Kokaly and others, 2017). The prefix “s07ASD_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_AV95 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 1995 (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV95_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_AV96 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 1996  (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV96_” is at the beginning of the ASCII, and GIF files.  
s07_AV97 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 1997 (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV97_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_AV98 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 1998 (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV98_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_AV99 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 1999 (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV99_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_AV00 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 2000 (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV00_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_AV01 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 2001 (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV01_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_AV05 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 2005 (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV05_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_AV06 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 2006 (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV06_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_AV09 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 2009 (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV09_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_AV10 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 2010 (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV10_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_AV11 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 2011 (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV11_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_AV12 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 2012 (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV12_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_AV13 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 2013 (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV13_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_AV14 – this is the name of the SPECPR file containing the spectral library measurements convolved to AVIRIS-Classic with spectral characteristics determined in the year 2014 (wavelength and bandpass values for the 224 channels provided with AVIRIS data by NASA/JPL). The prefix “s07_AV14_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_HY07 – this is the name of the SPECPR file containing the spectral library measurements convolved to Hyperspectral Mapper (HyMap) with spectral characteristics determined in the year 2007 (wavelength and bandpass values for the 124 channels provided with HyMap data by HyVista Corp). The wavelength and bandpass values were validated by comparing measurements of reference materials made using the HyMap 2007 imaging spectrometer to measurements of the same materials made on higher resolution laboratory spectrometers (the procedure is described in Kokaly (2011) and discussed in Kokaly and others (2013). The prefix “s07_HY07_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer.  
s07_HY14 – this is the name of the SPECPR file containing the spectral library measurements convolved to Hyperspectral Mapper (HyMap) with spectral characteristics determined in the year 2014 (wavelength and bandpass values for the 126 channels provided with HyMap data by HyVista Corp). The wavelength and bandpass values were validated by comparing measurements of reference materials made using the HyMap 2014 imaging spectrometer to measurements of the same materials made on higher resolution laboratory spectrometers (the procedure is described in Kokaly (2011) and discussed in Kokaly and others (2013). The prefix “s07_HY14_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer. 
s07HYPRN - this is the name of the SPECPR file containing the spectral library measurements convolved to the Hyperion imaging spectrometer. The oversampled spectra in splib07b were convolved to Hyperion’s average spectral characteristics (accessed January 10, 2017, at https://eo1.usgs.gov/sensors/hyperioncoverage). The prefix “s07HYPRN_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer. 
s07_VIMS – this is the name of the SPECPR file containing the spectral library measurements convolved to the Cassini spacecraft’s Visual and Infrared Mapping Spectrometer (VIMS) with spectral characteristics determined by Clark and others (2016), wavelength and bandpass values for the 352 channels. The prefix “s07_VIMS_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer. 
s07CRSMg – convolved to the global mapping mode of the Mars Reconnaissance Orbiter spacecraft’s Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) with spectral characteristics determined by Murchie and others (2009), wavelength and bandpass values for the 72 channels. The prefix “s07CRSMg_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer. 
s07CRSMj – convolved to the targeted mode (joined visible and infrared sensors) of the Mars Reconnaissance Orbiter spacecraft’s Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) with spectral characteristics determined by Murchie and others (2009), wavelength and bandpass values for the 489 channels. The prefix “s07CRSMj_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer. 
s07_M3t – convolved to the target mode of the Moon Mineralogy Mapper spectrometer with spectral characteristics determined by Green and others (2011), wavelength and bandpass values for the 256 channels. The prefix “s07_M3t_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer. 
s07ASTER – the library in SPECPR format, resampled to response functions of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The spectral response functions for this sensor’s nine bands covering the visible through shortwave infrared wavelengths came from NASA (ASTER instrument characteristics accessed January 3, 2017, at https://asterweb.jpl.nasa.gov/content/01_mission/03_instrument/archive/vnir.txt and https://asterweb.jpl.nasa.gov/content/01_mission/03_instrument/archive/swir.txt). The prefix “s07ASTER_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer. 
s07LSAT8 – the library in SPECPR format, resampled to response functions of Landsat-8 Operational Land Imager (OLI). The spectral response functions for this sensor’s seven bands covering the visible through shortwave infrared wavelengths came from spectral libraries included as part of the ENVI 5.3 software release. The ENVI data were compared to values of the pre-launch sensor response functions (Barsi and others, 2014; spreadsheet with values was accessed December 27, 2016, at http://landsat.gsfc.nasa.gov/?p=5779)  and found to be identical. The prefix “s07LSAT8_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer. 
s07SNTL2 – the library in SPECPR format, resampled to response functions of Sentinel-2 Multispectral Instrument (MSI). The spectral response functions for this sensor’s 13 bands covering the visible through shortwave infrared wavelengths came from the European Space Agency (ESA, 2015). The prefix “s07SNTL2_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer. 
s07_WV3 – the library in SPECPR format, resampled to response functions of WorldView3 (WV3). The spectral response functions for this sensor’s 16 bands covering the visible through shortwave infrared wavelengths came from DigitalGlobe (2016). The prefix “s07_WV3_” is at the beginning of the ASCII and GIF files pertaining to this spectrometer. 
Alternative SPECPR files containing only the spectra (and not the metadata) with consistent data record numbering from spectrometer to spectrometer are included in the folder “alternativeSPECPR”. The SPECPR files mentioned previously contain the resampled spectra along with their associated metadata descriptions. The filenames of these alternative SPECPR files are similar to those listed previously, except all characters are in lowercase. 
The spectra in the data release are organized in these chapters:  
Chapter M = Minerals 
Chapter S = Soils (including rocks and mineral mixtures) 
Chapter C = Coatings 
Chapter L = Liquids (including mixtures of liquids, water and other volatiles, and frozen volatiles) 
Chapter O = Organics (including biochemical constituents of plants and chemical compounds) 
Chapter A = Artificial (manmade materials, including construction materials, fabrics, manufactured chemicals, processed materials, paint pigments, plastics, and materials introduced into the environment by human activity) 
Chapter V = Vegetation (including biological materials, plant components such as leaves, flowers, and bark, vegetated areas having more than one species present, lichens, biological soil crusts, and mixtures with vegetation) 
Chapter M includes native elements and minerals from arsenate, borate, carbonate, halide, hydroxide, nitrate, oxide, phosphate, silicate (cyclosilicate, inosilicate, phyllosilicate, nesosilicate, sorosilicate, and tectosilicate), sulfate, and sulfide classes are represented. The chapter also contains compositional end- and intermediate-members for the olivine, garnet, scapolite, montmorillonite, muscovite, jarosite, and alunite solid-solution series. We have included representative spectra of kerogen, ammonium-bearing minerals, Lanthanide element oxides, desert varnish coatings, kaolinite crystallinity series, kaolinite-smectite series, zeolite series, and an extensive evaporite series. In some cases, a number of spectra span a compositional solid-solution series or a grain-size series or both. 
Some samples were not easily placed into a specific chapter. For example, pure minerals are often difficult to find, or it may be difficult to process the sample to purify the mineral. Such a sample could be considered a mixture. Some samples of this type were put in the minerals chapter (Chapter 1: M) because they have spectral features that are representative of one mineral in the sample. The mixture chapter (Chapter 2: S) contains spectra of multiphase samples used for identifying and mapping mixtures. Usually, the materials in these mixtures have overlapping absorption features in their spectra. The samples in the coatings chapter (Chapter 3: C) are also mixtures. However, the mineral coatings on the surfaces of the rock samples may be optically thick and obscure the spectral signatures of the underlying minerals. Frozen water, in the form of snow and ice, is included in Chapter 4: L. 
Organic compounds are a vast category with great chemical diversity. We have added more than 200 organic compounds to a new chapter in this release of the library (Chapter 5: O). The additions are focused on compounds of smaller molecular weight that form the functional groups for larger molecules. Major groups represented include alkanes, alkenes, alkynes, aromatic hydrocarbons based on the benzene ring, and amino acids. Many of these compounds are known by multiple names because of different naming conventions and use of the common name before systematic naming conventions were created. We endeavored to use the name that was in most common use in the spectrum titles. The sample description has the Chemical Abstract Services Registry Number. The metadata descriptions also list the various names that have been applied to a particular chemical. Biochemical constituents of plants are also in this chapter of the library. Spectra of major components of plants, including lignin, cellulose, amylose, and starch, and less abundant components, including many plant phenolics, were added. 
Terrestrial remote sensing may be used in urban areas covered by manmade materials, so the library includes spectra of plastics, roofing materials, processed wood, paint, and other artificial materials (Chapter 6: A). Also in this chapter are materials that might be considered natural, for example oil and vermiculite insulation; however, they are present in the environment because of human activity or they have been altered or concentrated during a manufacturing process. In the data release, spectra of oil residues from the British Petroleum (BP) Deepwater Horizon spill (DWH) have been added. Materials that we use to process spectra and monitor the performance of our spectrometers have been added, specifically, Spectralon and mylar plastic. 
The spectra in the vegetation chapter (Chapter 7: V) are representative of areas in which we have conducted research and for which we have published results, including: grasslands, semiarid shrublands, biological soil crusts, temperate evergreen forests, California chaparral, and coastal wetlands. The spectra span a range of measurement scales, from laboratory spectra of leaves, stems, flowers, and other plant components to remotely-sensed spectra of vegetated areas of mixed species. Because the SPECPR database file format has a limitation of 40 characters for spectrum titles, scientific names of organisms are rarely used in spectrum titles. Instead, scientific names are specified in the metadata descriptions of spectra. Spectra of leaves or a plant of a single species are often listed by a generic common name of the plant (for example, “manzanita” to represent Arctostaphylos viscida Parry). Field and AVIRIS spectra of mixed vegetation areas (plant communities) are sometimes listed by the common name of the dominant species (for example, lodgepole pine), by biome (such as grassland or shrubland), or by a land-use term (such as rangeland). In some cases, the title contains the biome name and the dominant species indicated by symbols comprising the genus and species of the dominant plant, for example, “Marsh_SPAL80%...” in the title describing a coastal wetland area where the most abundant species is Spartina alterniflora Loisel. with 80 percent (%) cover. 
Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 
References: 
Barsi, J. A., Lee, K., Kvaran, G., Markham, B.L., and Pedelty, J.A., 2014, The spectral response of the Landsat-8 operational land imager: Remote Sensing, v. 6 n. 10, p. 10232-10251. 
Clark, R.N., 1993, SPECtrum Processing Routines user's manual version 3 (program SPECPR): U.S. Geological Survey Open File Report 93–595, 210 p., software online, accessed November 3, 2016, at http://speclab.cr.usgs.gov/software.html 
Clark, R. N., R. H. Brown, and D. M. Lytle, 2016, The VIMS Wavelength and Radiometric Calibration, NASA Planetary Data System,  http://atmos.nmsu.edu/data_and_services/atmospheres_data/Cassini/vims.html 
DigitalGlobe, 2016, WorldView-3 Relative Radiometric Response Curves, Attachment A to Radiometric Use of WorldView-3 Imagery, accessed January 3, 2017, at https://dg-cms-uploads-production.s3.amazonaws.com/uploads/document/file/208/WV03_technote_raduse_AttachmentA.pdf. 
ESA (European Space Agency), 2015, Sentinel-2A Spectral Response Functions (S2A-SRF) COPE-GSEG-EOPG-TN-15-0007, accessed December 28, 2016, at https://earth.esa.int/documents/247904/685211/Sentinel-2A+MSI+Spectral+Responses. 
Green, R. O., C. Pieters, P. Mouroulis, M. Eastwood, J. Boardman, T. Glavich1, S Besse, D. Barr, B. Buratti, D. Cate, A. Chatterjee, R. Clark, L. Cheek, J. Combe, D. Dhingra, V. Essandoh, S. Geier, R. Green, V. Haemmerle, J. Head, L. Hoveland, S. Hyman, P. Isaacson, R. Klima, T. Koch, G. Kramer, K. Lee, S. Lundeen, E. Malaret, T. McCord, J. Mustard, J. Nettles, N. Petro, K. Plourde, C. Racho, J. Rodriquez, C. Runyon, G. Sellar, C. Smith, H. Sobel, M. Staid, J. Sunshine, L Taylor, S. Tompkins, H. Tseng, G. Vane, P. Varanasi, M. White, and D. Wilson, 2011. The Moon Mineralogy Mapper (M3) Imaging Spectrometer for Lunar Science: Instrument Description, Calibration, On-Orbit Measurements, Science Data Calibration and Initial On-Orbit Validation, J. of Geophysical Research E00G19, doi:10.1029/2011JE003797.  
Kokaly, R.F., 2011, PRISM—Processing routines in IDL for spectroscopic measurements (installation manual and user's guide, version 1.0): U.S. Geological Survey Open-File Report 2011–1155, 432 p, accessed November 3, 2016, at http://pubs.usgs.gov/of/2011/1155/. 
Kokaly, R.F., King, T.V.V., and Hoefen, T.M., 2013, Surface mineral maps of Afghanistan derived from HyMap imaging spectrometer data, version 2: U.S. Geological Survey Data Series 787, 29 p., accessed November 3, 2016, at http://pubs.usgs.gov/ds/787/. 
Kokaly, R.F., and Skidmore, A.K., 2015, Plant phenolics and absorption features in vegetation reflectance spectra near 1.66 µm: International Journal of Applied Earth Observation and Geoinformation, v. 43, p. 55-83, accessed November 3, 2016, at http://dx.doi.org/10.1016/j.jag.2015.01.010.  
Kokaly, R.F., Clark, R.N., Swayze, G.A., Livo, K.E., Hoefen, T.M., Pearson, N.C., Wise, R.A., Benzel, W.M., Lowers, H.A., Driscoll, R.L., and Klein, A.J., 2017, USGS Spectral Library Version 7: U.S. Geological Survey Data Series 1035, 61 p., https://doi.org/10.3133/ds1035. 
Murchie, S. L., F. P. Seelos, C. D. Hash, D. C. Humm, E. Malaret, J. A. McGovern, T. H. Choo, K. D. Seelos, D. L. Buczkowski, M. F. Morgan, O. S. Barnouin-Jha, H. Nair, H. W. Taylor, G. W. Patterson, C. A. Harvel, J. F. Mustard, R. E. Arvidson, P. McGuire, M. D. Smith, M. J. Wolff, T. N. Titus, J.-P. Bibring, and F. Poulet (2009), The Compact Reconnaissance Imaging Spectrometer for Mars investigation and data set from the Mars Reconnaissance Orbiter's primary science phase, J. Geophys. Res., 114(CRISM special issue), doi:10.1029/2009JE003344.

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Organization: Department of the Interior