Applying Analytics

2-Dimensional Data Sets 159

not possible to determine whether the small closed contour at −72

◦

W and

38.5

◦

N corresponds to an increase or decreas e in depth. From look ing directly

at the data, it turns out that this is a small depression in the sea floor. By

leaving this ambiguity in the contour’s value, I made a mistake in drawing

the contour plot. I did not correct the error because I wanted to demonstrate

how careful you need to be when making these plots – there is a lot of detail

to pay attention to. In fa c t, similar concerns could be raised about many of

the contours drawn below s e a level.

In Section 7.5.1, I will discuss the climate data set and display more e x-

amples of contour plots. The climate data set is a particularly good example ...