SoilGrid.validator(obj, domain, ground.truth, N.sample=2000, xml.file, z.lim, md.type="INSPIRE", test.URL=FALSE)"GDALobj" object i.e. a pointer to a spatial layer of interest (single slice)"GDALobj" object i.e. a pointer to a spatial layer contain soil mask"SpatialPointsDataFrame"; contains values of the target variable at exactly the same depth / same support size sampled either using Simple Random Sampling or regular sampling on a gridobj file)plotKML::spMetadata