Spatial heterogeneity analysis and source identification of heavy metals in soil: a case study of Chongqing, Southwest China

Chemical and Biological Technologies in Agriculture

Table 3 Cross-validation results of the four interpolation methods for As, Cu, and Mn

Element	Interpolation method	RMSE	ME	IP²
As	OK	2.827	− 0.036	7.988
	IDW	3.108	0.079	9.653
	LPI	2.978	0.015	8.868
	RBF	3.240	0.067	10.493
Cu	OK	7.125	− 0.120	50.749
	IDW	7.495	0.057	56.166
	LPI	7.012	− 0.026	49.170
	RBF	7.119	0.024	50.688
Mn	OK	162.305	− 0.249	26,342.950
	IDW	170.745	− 0.712	29,153.501
	LPI	176.729	0.078	31,233.405
	RBF	171.962	1.556	29,568.343