Normalized Difference Enhanced Sand Index for desert sand dunes detection using Sentinel-2 and Landsat 8 OLI data, application to the north of Figuig, Morocco

Abstract

This paper discusses developing a novel spectral index for desert sand dunes detection using four bands from Sentinel-2 data. This index, called Normalized Difference Enhanced Sand Index (NDESI), uses the blue band (492 nm), the red (664 nm) or the Vegetation Red Edge (VRE) band (782 nm), and two of the Shortwave Infrared (SWIR) bands (1613 and 2202 nm) to generate a grayscale image, where DN values are within −2 to 2. The lowest and highest values represent water bodies and sand dunes, respectively. A threshold calculation technique was used to generate a unique threshold for each image. This index application on several images covering the northern region of Figuig city seems to perfectly highlight sand dunes all over the image, with an overall accuracy of 97.9% and a kappa coefficient of 83.4%. This index is adapted for Landsat 8 data and can track sand dunes change over time.