Glossary

Enhanced Thematic Mapper Plus (ETM+)

The sensor aboard Landsat 7 that picks up solar radiation reflected by or emitted from the Earth. It is an enhanced version of the Thematic Mapper (TM).

For more information, see NASA: The Enhanced Thematic Mapper Plus, Glossary: Thematic Mapper (TM)

Ephemeris

A table of satellite orbital locations for specific time intervals. The ephemeris data helps characterise the conditions under which remotely sensed data is collected and is commonly used to correct the sensor data before analysis.

European Space Agency (ESA)

A European intergovernmental organisation dedicated to the exploration of space. Established in 1975 and headquartered in Paris, it currently comprises 22 member states. 

For more information, see ESA

External product

A product that was not generated by GA. These products have fewer information field requirements.