NDBI (Normalized Difference Built-up Index)

Normalized Differential Build-up Index (NDBI) is a way of measuring the extent and density of built-up areas using the near-infrared and shortwave infrared bands of the spectrum. It is calculated by comparing the amount of shortwave infrared light (which built-up areas reflect strongly) and near-infrared light (which built-up areas absorb) that is reflected by the land cover. NDBI values range from -1 to +1, where higher values indicate more built-up areas and lower values indicate less or no built-up areas.

NDBI = (SWIR - NIR) / (SWIR + NIR)