geoprimsField-grade geospatial math

NDBI

The normalized difference built-up index from shortwave-infrared and near-infrared reflectance, which highlights roofs, roads, and other built surfaces.

Experimental: not yet fully verified. How results are checked

0.0877

NDBI is 0.0877.

Provenance
Computed by
raster.index.ndbi 1.0.0, core 0.1.0
Model
NDBI = (SWIR1 - NIR) / (SWIR1 + NIR) on surface reflectance (Zha, Gao, and Ni 2003)
Accuracy
Exact arithmetic on the reflectance given.
Notes
1 shown with the answer
Cites
Zha, Y., Gao, J., and Ni, S., International Journal of Remote Sensing, Use of normalized difference built-up index in automatically mapping urban areas from TM imagery

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How we got thisFormula, worked example, sources, and proof

Model: NDBI = (SWIR1 - NIR) / (SWIR1 + NIR) on surface reflectance (Zha, Gao, and Ni 2003)

Accuracy: Exact arithmetic on the reflectance given.

When to use this: Use this to separate built surfaces from vegetation: roofs, pavement, and bare construction reflect shortwave-infrared more than near-infrared, so they come out positive while vegetation is negative. It is usually read beside NDVI rather than alone.

Limitations: Bare soil and dry ground behave much like built-up surfaces here, which is the index's main weakness, and the original work paired it with NDVI to tell them apart. It is not a measure of impervious fraction, and the result depends on the sensor's shortwave band.

Worked example: NDBI. Source: Zha and others 2003: SWIR1 0.31 and NIR 0.26 give 0.0877. It is golden test vector v004, and every build checks the tool still gives its answer within its tolerance.

You enter

Near-infrared reflectance
0.26
Shortwave-infrared reflectance
0.31

You get

NDBI
0.0877

Review: Not yet independently reviewed by a GIS professional.

Last verified: 2026-09-22, when a maintainer last confirmed this tool's sources at the issuer. See the sources ledger.

Status: version 1.0.0, core 0.1.0. See this tool in the verification report.

Checked against: 10 golden test vectors (download the test vectors, each with its source and tolerance). See how results are checked and every source.

Sources

Terms

NDBI: normalized difference built-up index
The difference between shortwave-infrared and near-infrared reflectance over their sum, which highlights roofs, pavement, and bare construction. Source: Use of normalized difference built-up index in automatically mapping urban areas from TM imagery

Experimental means this tool has not yet met the stable bar: at least 20 golden vectors, differential tests, and an independent worked example.