# Geological Cross Section¶

Plot a geological cross section in 3D space.

We have a cross section PNG image and we know three coordinates along that section: * This section goes from +200m to -2000m in vertical extent * Coordinates of the start point: 32362837 5769796 * Coordinates of the bend: 32368424 5765456 (the bending point is indicated with a * “K” at around half the section) * Coordinates of the end point: 32374114 5763507

Originally posted: https://github.com/pyvista/pyvista-support/issues/272

```import pyvista as pv
from pyvista import examples
import numpy as np
```

Parameters for cross section

```zrng = [-2000, 200]
start = [32362837, 5769796]
bend = [
32368424,
5765456,
]  # (the bending point is indicated with a "K" at around half the section)
end = [32374114, 5763507]
```
Make a surface mesh representing that coverage/ This mesh consists of 6 points. Generate them:

a—–b—–e | | | | | | d—–c—–f

```a = start + [
zrng,
]
b = bend + [
zrng,
]
c = bend + [
zrng,
]
d = start + [
zrng,
]
e = end + [
zrng,
]
f = end + [
zrng,
]
```

Now make a poly data mesh of these points

```points = np.array([a, b, c, d, e, f])
faces = np.array([4, 0, 1, 2, 3, 4, 1, 4, 5, 2])
surface = pv.PolyData(points, faces)
```

Map the texture to the mesh. - We know the tcoords of a, d, e, & f, but not necessarily b & c - to find them, scale by cell sizes: - Get the width of the two cells to find those coords

```w = surface.compute_cell_sizes()["Area"] / np.ptp(zrng)
tw = (w / np.sum(w))

# Generate Tcoords now!
t_coords = np.array(
[
[0, 1],
[tw, 1],
[tw, 0],
[0, 0],
[1, 1],
[1, 0],
]
)
surface.t_coords = t_coords
```

```path, _ = examples.downloads._download_file("geo-cross-section.png")
texture = pv.Texture(path)
```

Plot it up!

```cpos = [
(32361897.379640546, 5777033.66791174, 341.48314909204873),
(32366747.758752592, 5766374.637744438, -1142.521946006218),
(0.047926147231751065, -0.11631040130754997, 0.9920559333823861),
]
surface.plot(texture=texture, cpos=cpos, show_edges=True)
``` Out:

```[(32361897.379640546, 5777033.66791174, 341.48314909204873),
(32366747.758752592, 5766374.637744438, -1142.521946006218),
(0.047926147231751065, -0.11631040130754997, 0.9920559333823861)]
```

Total running time of the script: ( 0 minutes 2.199 seconds)

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