The AVIRIS Concept

The AVIRIS instrument contains 224 different detectors, each with a wavelength sensitive range (also known as spectral bandwidth) of approximately 10 nanometers (nm), allowing it to cover the entire range between 380 nm and 2500 nm. When the data from each detector is plotted on a graph, it yields a spectrum. Comparing the resulting spectrum with those of known substances reveals information about the composition of the area being viewed by the instrument.

AVIRIS uses a scanning mirror to sweep back and forth ("whisk broom" fashion), producing 614 pixels for the 224 detectors each scan. Each pixel produced by the instrument covers an approximately 20 meter square area on the ground (with some overlap between pixels), thus yielding a ground swath about 11 kilometers wide.

The ground data is recorded on board the instrument along with navigation and engineering data and the readings from the AVIRIS on-board calibrator. When all of this data is processed and stored on the ground, it yields approximately 140 Megabytes (MB) for every 512 scans (or lines) of data. Each 512 line set of data is called a "scene", and corresponds to an area about 10km long on the ground.

Every time AVIRIS flies, the instrument takes several "runs" of data (also known as "flight lines"). AVIRIS tapes have had anywhere from one to fifteen runs on them, with each run having anywhere from one to almost forty scenes. A full AVIRIS tape can yield about 16 Gigabytes (GB) of data per day.

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Contact information

Ordering AVIRIS Data:: avorders@ophelia.jpl.nasa.gov
Questions about AVIRIS:: question@ophelia.jpl.nasa.gov
Technical queries about AVIRIS data and quicklooks:: av_tech@ophelia.jpl.nasa.gov
Comments and suggestions for improving this documentation:: av_tech@ophelia.jpl.nasa.gov

Last update: 7 Dec 1995

Lisa M. Barge / lisab@gomez.jpl.nasa.gov / AVIRIS Data Facility