ex08_gap_limits
This example extends the gap-size limit from merge2d ex09 into three
dimensions. A smooth reference model contains three missing cylinders:
A small internal gap with a 16 km distance between its finite z brackets.
A large internal gap with a 44 km bracketing distance.
A gap connected to the top of the model at
z = 0.
The limited reconstruction uses:
gmt merge3d model.nc?gapped -R0/100/0/100 -I2 -T0/100/1 \
-Fvalue -Sl+g20 -nl -Glimited.nc
The +g20 modifier bridges a missing vertical run only when the distance
between its finite z brackets is no more than 20 km. Consequently, the small
gap is filled while the large gap remains missing. The unrestricted result
uses -Sl+g and fills both internal gaps.
The gap touching z = 0 remains missing in both reconstructions because gap
bridging does not extrapolate beyond the vertical coordinate range of finite
data. The limit is evaluated independently for every vertical column; it is a
z-coordinate distance, not a three-dimensional diameter.
This example intentionally omits -H because it isolates the vertical
z-distance limit. The separate -H+m<maxgap> modifier limits horizontal holes
by their x and y spans in grid nodes, matching merge2d.
Panels (a-d) show horizontal slices at z = 50 km. Panels (e-h) show vertical
sections along y = 50 km, where the top-connected gap is also visible. Blue,
orange, and black dashed outlines identify the small, large, and edge-connected
gaps, respectively. The dashed black line in the horizontal panels marks the
vertical-section location.
Run:
./ex08_gap_limits.sh
The script verifies the expected state of all three gaps for the original,
limited, and unrestricted results. It creates ex08_gap_limits.png and
ex08_gap_limits.pdf.
Figures
