USGS Spectroscopy Laboratory

USGS Spectral Library Version 7

Explore and download spectra | Spectral library publication | Data Release

Example sample and spectra.
Example spectra and sample photo.

Spectral Library Links

  • Interactive website with the current version of the library: USGS Spectral Library Version 7
  • USGS publication and official citation for the current version of the library:
    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.
  • USGS Data Release (ScienceBase - download zip file with all library files):
    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 Data: U.S. Geological Survey data release, https://dx.doi.org/10.5066/F7RR1WDJ.
  • Access software to read SPECPR versions of the spectral library: Software for Library Files in SPECPR format

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Spectral Library Description

Researchers at the USGS Spectroscopy Laboratory have measured the spectral reflectance of thousands of materials in the lab and compiled them in the USGS Spectral Library.

  • The spectral library was assembled to facilitate laboratory and field spectroscopy and remote sensing for identifying and mapping minerals, vegetation, and manmade materials.
  • For many of the samples, wavelength coverage spans the ultraviolet, visible, near-infrared, mid-infrared, and far-infrared regions (0.2 to 200 microns).
  • A wide range of materials are included in the library:
    • Minerals
    • Soils (including rocks, and mineral mixtures)
    • Coatings on rock surfaces
    • Liquids, including mixtures of liquids, water and other volatiles, and frozen volatiles
    • Organic compounds, including biochemical constituents of plants and chemical compounds
    • Manmade materials, including materials introduced into the environment by human activity
    • Vegetation and other biologic materials
  • Detailed sample descriptions are provided with the spectra, including the results of X-ray Diffraction, Electron Probe Micro-Analysis, and other analytical methods.

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Software for SPECPR Files

SPECPR files provided in the library contain spectra along with linked sample descriptions.

Free software is available for reading spectral library files in SPECPR format:

  • PRISM (Processing Routings in IDL for Spectroscopic Measurements)
    • A graphical user interface for working with spectra in SPECPR files (such as the USGS spectral library).
    • Can be installed as a plug-in to ENVI.
    • Can run as an IDL Virtual Machine application without need for an ENVI license.
    • Includes a programmer’s interface so that functions can be called from user’s code.
    • Users can define and search for character strings (keywords) in the titles of spectra and/or in their associated metadata descriptions.
  • SPECPR (SPECtrum Processing Routines)
    • A command line interface for SPECPR files.
    • Has a macro scripting capability.

Both software packages run in UNIX, LINUX, Microsoft Windows, and Apple Macintosh operating systems.

These programs allow users to:

  • plot spectra
  • read sample descriptions
  • analyze spectral features
  • convolve spectra to the characteristics of other spectrometers and sensors
  • export spectra to other file formats

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Superseded Spectral Library Versions

NOTE: USGS Spectral Library Version 7 supersedes older versions of the library, although versions 4, 5, and 6 may still be accessed here.

Spectral Library 6 (2007)

Clark, R.N., Swayze, G.A., Wise, R.A., Live, K.E., Hoefen, T.M., Kokaly, R.F., and Sutley, S.J., 2007, USGS Digital Spectral Library splib06a: U.S. Geological Survey Data Series 231. View Spectral Library 06.

The UV to mid-infrared 0.2-150 micron library (splib06) contains over 1300 spectra including mid-infrared data as well as spectra from Spectral Library Version 05 and additional visible and near-infrared spectra. The library includes many more minerals, organic and volatile compounds, vegetation, and man-made materials than our previous libraries. The database is over 6,000 web pages, figures, sample images and data listings.

Spectral Library 5 (2003)

Clark, R.N., Swayze, G.A., Wise, R.A., Livo, E., Hoefen, T.M., Kokaly, R.F., and Sutley, S.J., 2003, USGS Digital Spectral Library splib05a: U.S. Geological Survey Open-File Report 2003-395, 5 figs, 3 tables. View Spectral Library 05.

The library contains spectral covering wavelengths from the ultraviolet to near-infrared along with sample documentation and spectra from Spectral Library Version 4. The library includes samples of minerals, rocks, soils, physical constructed as well as mathematically computed mixtures, vegetation, microorganisms, and man-made materials.

Spectral Library 4 (1993)

Clark, R.N., Swayze, G.A., Gallagher, A.J., King, T.V.V., and Calvin, W.M., 1993, The U.S. Geological Survey, Digital Spectral Library: Version 1 (0.2 to 0.3 μm): U.S. Geological Survey Open-File Report 93-592, 1326 p. View Spectral Library 04.

Spectral Library 4 (splib04a) includes original laboratory as well as instrument spectral libraries for terrestrial and planetary spectrometers.

Older Versions

For your information, libraries 01, 02, and 03 were experimental exercises on what to include in a spectral library.

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