Click on image to enlarge.

Figure 30. Some potential-field workers use 2nd derivative maps of magnetic data to bring out subtle anomalies, and here I show a 2nd derivative map of the same area of NewMag data in the Powder River Basin as shown in Figure 4. The well spots indicate that the fields essentially lie on the gradients of this map as well. However, NewMag is generally of higher resolution, the reason why I prefer it.