Glossary - D

Tools| A| B| C| D| E| F| G| H| I| J| K| L| M| N| O| P| Q| R| S| T| U| V| W| X| Y| Z| All

Data Continuity - A NASA requirement to ensure that Landsat 7 data are compatible to those obtained by earlier Landsat satellites.

Data set - A logically meaningful grouping or collection of similar or related data.

Descending node - Direction a satellite is traveling relative to the Equator. A descending node implies a southbound Equatorial crossing.

Digital - A means for encoding information in a communications signal by using bits (binary digits). Conversion of information into bits of data for transmission through wire, fiber optic cable, satellite, or over air techniques. Method allows simultaneous transmission of voice, data or video.

Downlink - A communications channel for receiving transmissions from a spacecraft.

Dynamic Range - The range between the maximum and minimum amount of input radiant energy that an instrument can measure.