Geoscience Reference
In-Depth Information
Plot amplitude range
Plot amplitude range
-100
-20
-40
-50
90
90
60
60
30
30
0
0
0.0
0.0
29.3
58.7
88.0
29.3
58.7
88.0
385447. to 395509.
395447. to 395509.
Easting
Easting
fIGURe 6.13
Contour shaded magnetic maps using different amplitude cutoff values.
Color scale
-48
200
30
20
10
0
Profile A
96
0
30
Distance
60
64
30
20
10
0
Profile B
32
0
30
Distance
60
0
0.0
29.7
395451. to 395515.
Contoured Grid
59.3
89.0
fIGURe 6.14
Extraction of profile lines from gridded data.
locate and define anomalies. If the orientation of an object of search is known, and the object is
elongated in one direction, then profile lines may be the preferred means to find the location of the
object. Profile lines may also be used to extract data from gridded data for modeling. Profiles can
be extracted from the gridded data and can be stacked in their relative spatial position based on a
level of the variable representing the position of the profile. The resulting stacked profile map gives
a three-dimensional view of the data set focusing on the shorter wavelength components that may
be lost in the normal contouring process. A simulated profile extraction from a set of gridded data
is shown in Figure 6.14.
6.5.2 i
n t e R P R e t a t i of n
Interpretation of EM data is conducted as different levels of complexity, depending upon the objec-
tive. A simple metal detector beeps when it supposedly passes over a very shallow buried object,
and EM data measured with more sophisticated geophysical instruments need to be plotted and
