Fig 1.
Geological map of Perak state (digitized from geological map of Peninsular Malaysia 1985 using Arc GIS Pro software).
Fig 2.
Histogram of radon activity concentration distribution in soil and statistical indicators.
Fig 3.
Map of radon activity concentration in soil gas Perak state.
Fig 4.
Box plot of radon activity concentration in geological formations of Perak state.
Table 1.
Soil gas permeability classifications [23].
Fig 5.
Box plot of soil gas permeability of Perak state.
Fig 6.
Box plot of soil gas permeability in geological units.
Fig 7.
Soil permeability map of Perak state.
Fig 8.
Box plot of GRP classification Perak state.
Fig 9.
Geogenic radon potential map of Perak state Malaysia.
Fig 10.
Semi-variogram.
Table 2.
Cross-validation results for model.
Fig 11.
Standard error of prediction map for GRP.