Summary
Calculates the Normalized Difference Water Index (NDWI) from a multiband raster object and returns a raster object with the index values.
Discussion
The Normalized Difference Water Index (NDWI) is an index for delineating and monitoring content changes in surface water. It is computed with the near-infrared (NIR) and green bands.
NDWI = (Green - NIR) / (Green + NIR)For information about other multiband raster indexes, see the Band Arithmetic raster function.
The referenced raster dataset for the raster object is temporary. To make it permanent, you can call the raster object's save method.
Syntax
NDWI (raster, {nir_band_id}, {green_band_id})| Parameter | Explanation | Data Type |
raster | The input raster. | Raster |
nir_band_id | The band ID of the near-infrared band. The ID index uses one-based indexing. (The default value is 5) | Integer |
green_band_id | The band ID of the green band. The ID index uses one-based indexing. (The default value is 3) | Integer |
| Data Type | Explanation |
| Raster | The output raster object with the NDWI index values. |
Code sample
Calculates the Normalized Difference Water Index for a Sentinel-2 image.
import arcpy
NDWI_raster = arcpy.ia.NDWI("Sentinel2.tif", 8, 3)