Add intersection.rst to docs

doc/source/index.rst

@@ -12,3 +12,5 @@
 
    skspatial.objects
    skspatial.measurement
+
+   intersection

doc/source/intersection.rst

@@ -0,0 +1,77 @@
+
+Intersection
+============
+
+Line-Line intersection
+----------------------
+
+The intersection of a `Line` with a `Line` is a `Point`.
+
+>>> from skspatial.objects import Point, Vector, Line
+
+>>> line_a = Line(Point([0, 0]), Vector([1, 1]))
+>>> line_b = Line(Point([10, 0]), Vector([0, 1]))
+
+>>> line_a.intersect_line(line_b)
+Point([10. 10.  0.])
+
+
+In order to intersect, the lines must be coplanar and not parallel. An error is returned otherwise.
+
+>>> line_b = Line(Point([10, 0]), Vector([1, 1, 1]))
+>>> line_a.intersect_line(line_b)
+Traceback (most recent call last):
+...
+dpcontracts.PreconditionError: The lines must be coplanar.
+
+>>> line_b = Line(Point([10, 0]), Vector([1, 1]))
+>>> line_a.intersect_line(line_b)
+Traceback (most recent call last):
+...
+dpcontracts.PreconditionError: The lines must not be parallel.
+
+
+
+Line-Plane intersection
+-----------------------
+
+The intersection of a `Line` with a `Plane` is a `Point`.
+
+>>> from skspatial.objects import Plane
+
+>>> line = Line(Point([5, 5, 3]), Vector([0, 0, -1]))
+>>> plane = Plane(Point([0, 0, 0]), Vector([0, 0, 1]))
+
+>>> plane.intersect_line(line)
+Point([5. 5. 0.])
+
+
+The line must not be parallel to the plane.
+
+>>> line = Line(Point([5, 5, 3]), Vector([0, 1, 0]))
+>>> plane.intersect_line(line)
+Traceback (most recent call last):
+...
+dpcontracts.PreconditionError: The line and plane must not be parallel.
+
+
+
+Plane-Plane intersection
+-----------------------
+
+The intersection of a `Plane` with a `Plane` is a `Line`.
+
+>>> plane_a = Plane(Point([0, 0, 0]), Vector([-1, 1, 0]))
+>>> plane_b = Plane(Point([8, 0, 0]), Vector([1, 1, 0]))
+
+>>> plane_a.intersect_plane(plane_b)
+Line(point=Point([4. 4. 0.]), direction=Vector([ 0.  0. -1.]))
+
+
+The planes must not be parallel.
+
+>>> plane_b = Plane(Point([8, 0, 0]), Vector([-1, 1, 0]))
+>>> plane_a.intersect_plane(plane_b)
+Traceback (most recent call last):
+...
+dpcontracts.PreconditionError: The planes must not be parallel.