Given 2 geometries a and b, a.Touches(b) is true if and only if the intersection of the interior of a and the interior of b is empty and the intersection of a and b is not empty.
Remarks:
A Point cannot touch a Point because a Point has no boundary and so the intersection of the interiors of the two geometries is not empty.
A Point can touch a non-closed Line at one of the end points of the Line.
A Point cannot touch a closed Line because all of the points in the Line are interior to it.
Illustration
e are MultiPoint geometries and f is a LineString.
