fragmentation detection, forest change detection, world agriculture supply and demand estimates, wildfire management, and coastal change analysis.
Recently, the Landsat Advisory Group of the National Geospatial Advisory Committee15 was asked by the Department of the Interior to investigate the feasibility of once again charging for Landsat data. The Group strongly advised that Landsat data should continue to be distributed at no cost. It found that charging for Landsat data would
• Severely restrict data use;
• Violate existing Office of Management and Budget guidelines, federal law, Office of Science and Technology Policy, and U.S. National Space Policy,
• Require statutory changes;
• Cost more than the amount of revenue generated by the charges;
• Create a circular payment basis for public agencies;
• Stifle the innovation and business activity that create jobs;
• Inhibit data analysis in scientific and technical analyses;
• Negatively impact international relations with respect to national, homeland, and food security; and
• Negatively impact foreign policy and U.S. standing as the leader in space technology.
To meet the requirements for continuity in the face of technological development and ongoing understanding of the land surface, the Sustained and Enhanced Land Imaging Program (SELIP) relies on well-defined users with clear scientific or operational requirements so that program goals are clearly articulated. Because users of land imaging data are widely spread across the government and private sector, current and future users groups will be diverse and broadly inclusive. Agreement on a set of core measurements simplifies the development of standardized sensors, data archiving, processing, and dissemination.
Although it will always be difficult to satisfy every user need, the committee found remarkable consistency in user requirements. The core scientific and operational requirement for the SELIP is the capture and distribution of global, moderate-resolution (30-100 m), multispectral data products, enhanced by a panchromatic band at finer resolution. The suite of applications for analyses of the data requires the full range of spectral capabilities—visible, near infrared, shortwave infrared, and thermal infrared—but there are no requirements to provide all measurements on the same platform, nor to continue to fly the same sensor, nor to restrict future systems to the current viewing angles and swath width. It is no coincidence that these requirements echo the present capability of the Landsat sensor suite, because assuring continuity of the ongoing data stream is the key aim for the future program.
The following requirements would satisfy a broad range of key federal and nonfederal users, both scientific and operational:
• Spatial resolution
— 30 m except in the thermal band, which would have coarser spatial resolution.
— Finer resolution (10-15 m), perhaps in a panchromatic band, was desired by some.
• Spectral requirements
— Visible and near-infrared region (VNIR, 0.4-1.1 µm).
— Shortwave infrared region (SWIR, 1.2-2.8 µm).
— Thermal infrared region (8-12 µm, with some interest in 3.5-4.0 µm).
— Calibration sufficient to allow backwards-compatible comparisons of future image products to earlier image collections.
— A larger dynamic range in the VNIR region to prevent saturation over snow and clouds; this requirement has been met in the Landsat 8 Operational Land Imager, with its 12-bit instead of 8-bit quantization.
15 National Geospatial Advisory Committee-Landsat Advisory Group Statement on Landsat Data Use and Charges, September 18, 2012, available at http://www.fgdc.gov/ngac/meetings/september-2012/ngac-landsat-cost-recovery-paper-FINAL.pdf.