In learner-centred methods, the teacher/instructor is both a teacher and a learner at the same time. In the words of Lawrence Stenhouse, the teacher plays a dual role as a learner as well âso that in his classroom extends rather than constricts his intellectual horizonsâ.
Two-point perspective has one set of lines parallel to the picture plane and two sets oblique to it. Parallel lines oblique to the picture plane converge to a vanishing point, which means that this set-up will require two vanishing points. Walls in 2-point perspective, converging toward two vanishing points.
Analysis of the projection shows little distortion in an area the size of the US. The figure below shows the Albers Equal-Area Conic projection of the world with shorelines on a 15 degree graticule. The standard parallels are 20 and 60 degrees N. The central meridian is 90 degrees W. For more about these parameters and other projections, see Map Projection Basics.