Presswell's Notes.

Auckland Star, Volume LXIV, Issue 150, 28 June 1933, Page 18

Presswell's Notes.

USE OF CONTOURS. ■""" No. VII. The series of conventional signs draws near to a close with the publication below of the method of irdicating the shape of raised land. Next week the last of this series will bo published; this will take the form of an aerial photograph of a section of country with, the natural features represented on a map (plan) below. The use of contour lines to show topography (shape of the land) is clearly illustrated in the sketches below. Floods have submerged the land, leaving visible only the cone —the highest point in a small range. (See sketch A.) (Note: In all signs the artist has represented both sides of the mountain range in his contour lines. This is only to make their appearance coincide with those on a map and to avoid confusion. However, all contours shown above the heavy dividing line are purely imaginary.)

The contour line coincides with the water line.

The waters arc receding, and after they have dropped 100 ft the hill appears as at B. The dotted lines show £>oft drops. Note how contours, widen on the gently sloping saddle.

The water has dropped a further 100 ft. Note how the contours narrow on the steeply-sloping left side. Valleys and ridges can b. clearlv seen from the contours also.