Skip to main content

Table 1 Environmental covariates obtained from the WorldClim database, ASTER-GDEM, and Landsat-8 OLI/TIRS and applied in the modeling regime

From: Mapping soil nutrients via different covariates combinations: theory and an example from Morocco

Environmental covariates

Sources

Resolution

Resample resolution

Bioclimatic parameters

   

Annual mean temperature (bio_1)

Max temperature of the warmest month (bio_5)

Min temperature of the coldest month (bio_6)

Annual precipitation (bio_12)

WorldClim database version 2

10 min (~ 340 km2)

30 m

Terrain attributes

   

Elevation; slope; profile curvature; plan curvature, Multi-resolution Valley Bottom Flatness (MrVBF); Multi-resolution Ridge Top Flatness (MrRTF); Topographic wetness index (TWI); convergence index and aspect

ASTER-GDEM

30 m

30 m

Remote sensing indices

   

Normalized difference vegetation index (NDVI)

Transformed normalized difference vegetation index (TNDVI)

Soil adjusted vegetation index (SAVI)

Ratio vegetation index (RVI)

Difference vegetation index (DVI)

Chlorophyll vegetation index (CVI)

Landsat OLI 8

30 m

30 m

  1. All the input data were resampled at 30 m pixel size