Profiles and pseudo-sections

Between the flat station map and a full 3-D volume sit the per-line views: a profile of resistivity/phase along each survey line, and a pseudo-section that images one line as station (x) against period (a proxy for depth, y). These are the interpretive workhorses — the first place lateral and vertical structure show up together.

All figures are interactive Plotly panels; hover for values, zoom into a band of interest.

Load the survey

import os

from pycsamt.map import MapView


DATA = os.path.join(
    os.environ.get("PYCSAMT_DOCS_REPO_ROOT", "."), "data", "AMT", "WILLY_DATA"
)
mv = MapView.from_folder(DATA, recursive=True)
print(f"{mv.n_stations} stations, lines: {mv.lines}")

53 stations, lines: ('L18PLT', 'L22PLT')

Line profiles

MapView.profile draws apparent resistivity and phase for every station, grouped by line — the quickest read on how each line behaves across the frequency band.

fig = mv.profile()
fig.update_layout(height=560)
fig

Resistivity pseudo-section

MapView.pseudosection images apparent resistivity as station vs period. High frequencies (top) sense shallow structure, low frequencies (bottom) sense deep — so the vertical axis reads as increasing depth.

fig = mv.pseudosection(quantity="rho")
fig.update_layout(height=520)
fig

Phase pseudo-section

The phase pseudo-section of the same line complements resistivity: phase tracks the rate of change of resistivity with depth, so a phase high often flags a conductor the resistivity image only hints at.

fig = mv.pseudosection(quantity="phase")
fig.update_layout(height=520)
fig

Distance along the profile

Setting x_axis="distance" spaces stations by their true separation (metres) instead of by index — important when station spacing is uneven, so lateral features are not distorted.

fig = mv.pseudosection(quantity="rho", x_axis="distance")
fig.update_layout(height=520)
fig

Next. A pseudo-section flattens one line. The fence diagram hangs every line’s section in a single 3-D scene at its true map position.