LibGrid
Satellites
Non-military satellites that provide imagery world-wide:
| Satellite | commercial | panchromatic | spectral | company |
|---|---|---|---|---|
| GeoEye-1 | x | 0.5m | 1.65m | GeoEye (Space Imaging) |
| QuickBird | x | 0.61m | 2.44m | DigitalGlobe |
| Eros C | x | 0.82m | 3.28m | ImageSat |
| Ikonos | x | 0.82m | 3.28m | Space Imaging |
| Formosat-2 | o | 2m | 8m | Taiwan |
| Spot-5 | x | 2.5m | 10m | Spot Image |
| Landsat ETM+ | - | 15m | 30m | NASA |
| Landsat MSS | - | 30m | 60m | NASA |
| Modis | - | 500m | 1000m | NASA |
Landsat 7 or Landsat ETM+ (Enhanced Thematic Mapper) is the most available free source of high-resolution imagery.
Landsat 7 specification: 705km 95min orbit, coverage in 16 days.
Landsat channels: 1–7 for varying spectral wave lengths from infrared to thermal.
Landsat imagery can be downloaded at the GLCF (Global LandCover Facility).
The best available free source of elevation maps is SRTM (Space Shuttle Radar Topography Mission). Also available from the GLCF.
Global bathymetry is available from Smith&Sandwell.
They offer SRTM30 gap-filled global altimetry as well.