An image captured by a satellite sensor.

Advanced Land Observing Satellite (ALOS)

A Japanese satellite launched in 2006. After five years of service, the satellite lost power and ceased communication with Earth, but remains in orbit.

Advanced Spaceborne Thermal and Reflection radiometer (ASTER)

An imaging instrument onboard Terra, the flagship satellite of NASA's Earth Observing System (EOS) launched in December 1999. ASTER data is used to create detailed maps of land surface temperature, reflectance, and elevation.

For more information, see NASA: ASTER

Advanced Very-High Resolution Radiometer (AVHRR)

A radiation-detection sensor that can be used for remotely determining cloud cover and the surface temperature. AVHRR instruments are carried by the National Oceanic and Atmospheric Administration (NOAA) family of polar orbiting platforms and European MetOp satellites.

For more information, see ESA: AVHRR.

Aerosol optical depth

Aerosol optical depth is a measure of the extinction of the solar beam by dust and haze.


In the context of remote sensing, algorithms generally specify how to determine higher-level data products from lower-level source data. For example, algorithms prescribe how atmospheric temperature and moisture profiles are determined from a set of radiation observations originally sensed by satellite sounding instruments.

Analysis Ready Data (ARD)

Satellite data that has been processed to a minimum set of requirements and organised into a form that allows immediate analysis and interoperability through time and with other datasets.

Application Programming Interface (API)

A software intermediary that allows two applications to talk to each other.

Atmospheric correction

The process of removing the effects of the atmosphere on the reflectance values of images taken by satellite or airborne sensors.

Australian Geoscience Data Cube (AGDC)

A collaborative project between Geoscience Australia, CSIRO and NCI, which aims to provide better public access to NASA’s extensive Landsat archive. 

AGDC was replaced by Digital Earth Australia's Open Data Cube. 

For more information, see Glossary: Open Data Cube (ODC)


The angle of an object’s position from true north.