Table 1. The functional relationships of two pairs of scatterplots defined for spatial cross-correlation analysis.

Scatterplot	Abscissa (x-axis)	Ordinate (y-axis)		Effect
		Scattered points	Trend line
The first plot	x	f (y) = nWy	f (xy) = xy T Wx	x acts on y
The second plot	x	f (y) = nWy	f (xx) = xx T Wy	x acts on y
The third plot	y	f (x) = nWx	f (yx) = yx T Wy	y reacts on x
The fourth plot	y	f (x) = nWx	f (yy) = yy T Wx	y reacts on x