Iron Oxide Index (IOI) identifies iron oxide minerals on the Earth’s surface by comparing reflectance from specific spectral bands. IOI values range from 0 to +1, where higher values indicate the presence of iron-rich minerals or soils, and lower values indicate minimal or no iron oxide content. It is useful in geological mapping, mineral exploration, and environmental studies.

Firefly = (B049)/(B002)
Sentinel = (B04)/(B02)
Landsat 8-9 = (red)/(blue)