Geoscience Reference
In-Depth Information
15.0
12.5
10.0
7.5
5.0
2.5
0.0
15.0
12.5
10.0
7.5
5.0
2.5
0.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
Distance (m)
(a)
Distance (m)
(b)
15.0
12.5
10.0
7.5
5.0
2.5
0.0
15.0
12.5
10.0
7.5
5.0
2.5
0.0
N
0.0
5.0
10.0
15.0
20.0
25.0
30.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
Distance (m)
(c)
Distance (m)
(d)
fIGURe 28.3
Ground-penetrating radar (GPR) 9 to 15 ns (0.38 to 0.68 m depth interval) time-slice ampli-
tude map computer-processing results: (a) raw data; (b) signal saturation correction filter (SSCF) and signal
trace enveloping (STE); (c) SSCF, 2-D migration (2DM), and STE; and (d) SSCF, spatial background subtrac-
tion filter (SBSF), 2DM, and STE.
The Figure 28.3d GPR time-slice amplitude map processing sequence began with the SSCF,
then a spatial background subtraction filter (SBSF), followed by 2DM, and finally, STE. Not only is
the areal extent of the golf course green obvious, the herringbone subsurface drainage pipe pattern is
easily distinguishable. The SBSF used for the Figure 28.3d GPR time-slice amplitude map employed
a seven signal trace moving average sequence. The SBSF helped substantially by removing most
of the constructed soil layer response, thereby enhancing drainage pipe signals. Consequently, for
mapping golf course green subsurface drainage pipe systems, a computer-processing sequence of a
SSCF, a SBSF, 2DM, and STE is the best choice.
Figure 28.4 depicts the effects of different golf course green GPR field survey setups in rela-
tion to a time-slice amplitude map (1000 MHz center antenna frequency data) depiction of the
subsurface drainage system present. For reference, Figure 28.4a is an interpreted schematic map
showing the Muirfield Village Golf Club seventeenth hole USGA Method green areal extent (gray
shaded area) and drain line locations (solid black lines for strong evidence and dashed black lines
for weaker evidence). This schematic map is based on 250, 500, and 1000 MHz center antenna fre-
quency GPR data collected in July 2004.
All Figure 28.4 time-slice amplitude maps were produced using a computer-processing sequence
of a SSCF, a SBSF, 2DM, and STE. The Figure 28.4b time-slice amplitude map is based on a bidi-
rectional survey (two sets of parallel measurement transects oriented perpendicular to one another)
with a 1 m spacing distance between adjacent measurement lines. The complete subsurface drain-
age pipe network shows up very clearly in Figure 28.4b, given the possible exception of the far left
portion of the map. The Figure 28.4c time-slice amplitude map is based on a bidirectional survey
with a 2 m spacing distance between adjacent measurement lines. The main conveyance line and
the lateral drain lines in the lower half of the Figure 28.4c time-slice amplitude map still show
up well, but the rest of the subsurface drainage system is not nearly as visible. The Figure 28.4d
time-slice amplitude map is based on a bidirectional survey with a 3 m spacing distance between
