Category: Foundations
Band
A band is a single spectral channel in an image, measuring energy within a specific wavelength range.
Also known as: spectral band, channel
Expanded definition
A band is one layer of a multi-spectral image. Each band measures a different part of the electromagnetic spectrum such as blue, red, near-infrared (NIR), or shortwave infrared (SWIR).
Different bands respond differently to vegetation, water, soil, and built-up surfaces. That is why indices like NDVI combine two bands rather than using one band alone.
Bands are not interchangeable across sensors. Even if two bands have similar names, their wavelength ranges and calibration can differ, which matters when you compare or fuse datasets.
Related terms
Spectral Resolution
Spectral resolution describes how finely a sensor samples wavelengths and how narrow its bands are.
NDVI
NDVI is a vegetation index that uses red and near-infrared reflectance to approximate vegetation greenness and vigor.
Optical Imagery
Optical imagery measures reflected sunlight, providing rich spectral information but being sensitive to clouds and illumination.