Table 1.

The interaction relationship of Geodetector q statistic

Interaction relationship	Interaction effect
$q(X_1\cap X_2)$ < $Min(q(X_1),q(X_2))$	Weaken, nonlinear
$Min(q(X_1),q(X_2))$ < $q(X_1\cap X_2)$ < $Max(q(X_1),q(X_2))$	Weaken, univariate
$q(X_1\cap X_2)$ > $Max(q(X_1),q(X_2))$	Enhance, bivariate
$q(X_1\cap X_2)$ = $q(X_1)$ + $q(X_2)$	Independent
$q(X_1\cap X_2)$ > $q(X_1)$ + $q(X_2)$	Enhance, nonlinear

$X_1\cap X_2$ means the new stratum created by overlaying X₁ and X₂