Station maps and overlays

The starting point for every pycsamt.map view is a station map — a plan view of the survey with each site plotted at its true coordinates. The high-level MapView façade loads a whole survey once and renders it many ways; this example builds the map up from bare locations to a contoured apparent-resistivity surface.

Every figure below is a live Plotly map: drag to pan, scroll to zoom, and hover a station to read its values.

Load the survey

MapView.from_folder reads every EDI line under a folder into one geo-referenced view. WILLY_DATA has five lines and 128 stations.

import os

from pycsamt.map import MapView

# Card thumbnail: a pre-rendered static PNG (interactive figures below have
# no raster the gallery can thumbnail).

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 across {len(mv.lines)} lines: {mv.lines}")
print("geo-referenced:", mv.has_geo)

53 stations across 2 lines: ('L18PLT', 'L22PLT')
geo-referenced: True

Station locations

The simplest overlay, index, colours each station by its position along the line — enough to see the survey geometry. Hover any point for its ID and coordinates.

fig = mv.station(overlay="index")
fig.update_layout(height=560)
fig

Coloured by apparent resistivity

Switch the overlay to rho and pick a frequency: now each station is coloured by its apparent resistivity at ~100 Hz. Lateral resistivity variation across the survey becomes visible at a glance.

fig = mv.station(overlay="rho", component="xy", frequency=100.0)
fig.update_layout(height=560)
fig

Add an interpolated contour surface

show_contours=True interpolates the station values onto a grid and draws filled contours beneath the markers — a continuous resistivity map rather than discrete points.

fig = mv.station(
    overlay="rho",
    component="xy",
    frequency=100.0,
    show_contours=True,
    contour_levels=14,
)
fig.update_layout(height=600)
fig

Phase instead of resistivity

The same map keyed on impedance phase highlights different structure — phase responds to gradients in resistivity, so it often sharpens boundaries the resistivity map smooths over.

fig = mv.station(
    overlay="phase", component="xy", frequency=100.0, show_contours=True
)
fig.update_layout(height=600)
fig

Frequency is depth: compare two bands

Higher frequencies sense shallower structure. Rendering the same survey at ~1000 Hz (shallow) shows a different pattern than the ~100 Hz map above — the basis for reading a station map as a depth-dependent slice.

fig = mv.station(
    overlay="rho",
    component="xy",
    frequency=1000.0,
    show_contours=True,
    title="Apparent resistivity ~1000 Hz (shallow)",
)
fig.update_layout(height=600)
fig

Next. These plan views collapse all depth into one frequency. The following examples open up the third dimension — first as per-line profiles and pseudo-sections, then as full 3-D fence diagrams and volumes.