Summary
Calculates the Clay Minerals (CM) ratio from a multiband raster object and returns a raster object with the index values.
Discussion
The clay minerals ratio is a ratio of the SWIR1 and SWIR2 bands. This ratio leverages the fact that hydrous minerals such as the clays, alunite absorb radiation in the 2.0–2.3 micron portion of the spectrum. This index mitigates illumination changes due to terrain since it is a ratio.
Clay Minerals Ratio = SWIR1 / SWIR2- SWIR1 = pixel values from the short-wave infrared 1 band
- SWIR2 = pixel values from the short-wave infrared 2 band
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
ClayMinerals (raster, {swir1_band_id}, {swir2_band_id})| Parameter | Explanation | Data Type |
raster | The input raster. | Raster |
swir1_band_id | The band ID of the shortwave infrared 1 (SWIR1) band. The band ID index uses one-based indexing. (The default value is 6) | Integer |
swir2_band_id | The band ID of the shortwave infrared 2 (SWIR2) band. The band ID index uses one-based indexing. (The default value is 7) | Integer |
| Data Type | Explanation |
| Raster | The output raster object with the Clay Minerals ratio values. |
Code sample
Calculates the Clay Minerals ratio for a Sentinel-2 image.
import arcpy
ClayMinerals_raster = arcpy.sa.ClayMinerals("Sentinel2.tif", 11, 12)