Skip to main content
U.S. flag

An official website of the United States government

On the terminology of the spectral vegetation index (NIR – SWIR)/(NIR + SWIR)

January 1, 2011

The spectral vegetation index (ρNIR – ρSWIR)/(ρNIR + ρSWIR), where ρNIR and ρSWIR are the near-infrared (NIR) and shortwave-infrared (SWIR) reflectances, respectively, has been widely used to indicate vegetation moisture condition. This index has multiple names in the literature, including infrared index (II), normalized difference infrared index (NDII), normalized difference water index (NDWI), normalized difference moisture index (NDMI), land surface water index (LSWI), and normalized burn ratio (NBR), etc. After reviewing each term’s definition, associated sensors, and channel specifications, we found that the index consists of three variants, differing only in the SWIR region (1.2–1.3 µm, 1.55–1.75 µm, or 2.05–2.45 µm). Thus, three terms are sufficient to represent these three SWIR variants; other names are redundant and therefore unnecessary. Considering the spectral representativeness, the term’s popularity, and the “rule of priority” in scientific nomenclature, NDWI, NDII, and NBR, each corresponding to the three SWIR regions, are more preferable terms.

Publication Year 2011
Title On the terminology of the spectral vegetation index (NIR – SWIR)/(NIR + SWIR)
DOI 10.1080/01431161.2010.510811
Authors Lel Ji, Li Zhang, Bruce K. Wylie, Jennifer R. Rover
Publication Type Article
Publication Subtype Journal Article
Series Title International Journal of Remote Sensing
Index ID 70043293
Record Source USGS Publications Warehouse
USGS Organization Earth Resources Observation and Science (EROS) Center