I’m posting about the University of Maryland’s Global Land Cover Facility, a massive archive (13 terabytes and growing) of various kinds of satellite imagery and derived data, even though I suspect many readers of this blog are already familiar with it. Most of the data is freely downloadable, accessible through a browser-based interface, and georeferenced for use in GIS and satellite image analysis software. Images are typically at moderate resolution (15-250 meters per pixel); free access to Ikonos high-resolution imagery is available only to NASA-affiliated researchers. For multi-wavelength data, you can usually download separate images for every spectral band as well as composite images.
Direct satellite imagery includes:
ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer))
- L1B Imagery (three different sets of IR imagery at various resolutions, covering the spectral range of 0.52-11.65 microns)
Landsat (Multiple bands, visible and IR, at 15-60 meter resolution from all Landsat missions)
- Landsat ETM+
- Landsat MSS
- Landsat TM
MODIS (Moderate Resolution Imaging Spectroradiometer) (7 bands covering the visible and near-infrared ranges)
- 32-day Composites
- 16-day Composite
There are also many datasets derived from the multi-spectral satellite imagery and data from the Advanced Very High Resolution Radiometer (AVHRR).