| The united state geology society: http://www.usgs.gov/ |
| European space agency: http://www.esa.int |
| Nationa Areonautics and space asministration: http://www.nasa.gov/ |
| Earth observatory: http://earthobservatory.nasa.gov/ |
| The Earth observing system: http://eospso.gsfc.nasa.gov/ |
| Jet Propulsion laboratory: http://www.jpl.nasa.gov/ |
| Landsat page: http://geo.arc.nasa.gov/sge/landsat/landsat.html |
| GIS |
| Geocomputation: http://www.geocomputation.org |