feat(seaborn): implement column-stratigraphic (#4903)

## Implementation: `column-stratigraphic` - seaborn

Implements the **seaborn** version of `column-stratigraphic`.

**File:** `plots/column-stratigraphic/implementations/seaborn.py`

**Parent Issue:** #4573

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/pyplots/actions/runs/23121198560)*

---------

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Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

plots/column-stratigraphic/implementations/seaborn.py

@@ -0,0 +1,237 @@
+""" pyplots.ai
+column-stratigraphic: Stratigraphic Column with Lithology Patterns
+Library: seaborn 0.13.2 | Python 3.14.3
+Quality: 89/100 | Created: 2026-03-15
+"""
+
+import matplotlib.patches as mpatches
+import matplotlib.pyplot as plt
+import numpy as np
+import pandas as pd
+import seaborn as sns
+
+
+# Set seaborn theme for polished styling
+sns.set_theme(
+    style="ticks",
+    context="talk",
+    font_scale=1.0,
+    rc={"axes.linewidth": 1.2, "patch.linewidth": 1.5, "hatch.linewidth": 1.0},
+)
+
+# Data - synthetic sedimentary section (Western Interior Seaway)
+layers = [
+    {"top": 0, "bottom": 15, "lithology": "sandstone", "formation": "Dakota Fm", "age": "Late Cretaceous"},
+    {"top": 15, "bottom": 30, "lithology": "shale", "formation": "Graneros Sh", "age": "Late Cretaceous"},
+    {"top": 30, "bottom": 52, "lithology": "limestone", "formation": "Greenhorn Ls", "age": "Late Cretaceous"},
+    {"top": 52, "bottom": 65, "lithology": "shale", "formation": "Carlile Sh", "age": "Late Cretaceous"},
+    {"top": 65, "bottom": 78, "lithology": "siltstone", "formation": "Niobrara Fm", "age": "Late Cretaceous"},
+    {"top": 78, "bottom": 100, "lithology": "limestone", "formation": "Fort Hays Ls", "age": "Late Cretaceous"},
+    {"top": 100, "bottom": 118, "lithology": "conglomerate", "formation": "Morrison Fm", "age": "Late Jurassic"},
+    {"top": 118, "bottom": 140, "lithology": "sandstone", "formation": "Entrada Ss", "age": "Middle Jurassic"},
+    {"top": 140, "bottom": 162, "lithology": "shale", "formation": "Chinle Fm", "age": "Late Triassic"},
+    {"top": 162, "bottom": 180, "lithology": "dolomite", "formation": "Kaibab Fm", "age": "Early Permian"},
+]
+
+df = pd.DataFrame(layers)
+df["thickness"] = df["bottom"] - df["top"]
+df["mid_depth"] = (df["top"] + df["bottom"]) / 2
+df["col_width"] = 1.0
+
+# Use seaborn color palette for distinct lithology colors (colorblind-safe)
+lith_types = ["sandstone", "shale", "limestone", "siltstone", "conglomerate", "dolomite"]
+palette = sns.color_palette("colorblind", n_colors=len(lith_types))
+lith_color_map = dict(zip(lith_types, [sns.desaturate(c, 0.7) for c in palette], strict=True))
+
+lithology_styles = {
+    "sandstone": {"color": lith_color_map["sandstone"], "hatch": "...", "label": "Sandstone"},
+    "shale": {"color": lith_color_map["shale"], "hatch": "---", "label": "Shale"},
+    "limestone": {"color": lith_color_map["limestone"], "hatch": "+++", "label": "Limestone"},
+    "siltstone": {"color": lith_color_map["siltstone"], "hatch": "//", "label": "Siltstone"},
+    "conglomerate": {"color": lith_color_map["conglomerate"], "hatch": "ooo", "label": "Conglomerate"},
+    "dolomite": {"color": lith_color_map["dolomite"], "hatch": "xxx", "label": "Dolomite"},
+}
+
+# Age period background colors via seaborn palette
+age_bg_palette = sns.color_palette("pastel", n_colors=5)
+age_list = ["Late Cretaceous", "Late Jurassic", "Middle Jurassic", "Late Triassic", "Early Permian"]
+age_bg_colors = {age: (*age_bg_palette[i], 0.10) for i, age in enumerate(age_list)}
+
+total_depth = 180
+
+# Build thickness data for side panel (seaborn distinctive feature)
+thickness_df = df[["lithology", "thickness"]].copy()
+thickness_df["lithology"] = thickness_df["lithology"].str.title()
+
+# Plot - three-panel layout: age brackets | stratigraphic column | thickness strip
+fig, (ax_age, ax, ax_thick) = plt.subplots(1, 3, figsize=(16, 9), width_ratios=[0.16, 0.54, 0.30])
+
+# Use sns.barplot for the lithology layers (seaborn plotting function)
+sns.barplot(
+    data=df,
+    y="formation",
+    x="col_width",
+    color="#306998",
+    ax=ax,
+    edgecolor="black",
+    linewidth=1.5,
+    order=df["formation"].tolist(),
+    width=0.98,
+)
+
+# Reposition bars from categorical to proportional depth scale and add hatching
+col_width = 0.55
+for i, (_, row) in enumerate(df.iterrows()):
+    bar = ax.patches[i]
+    style = lithology_styles[row["lithology"]]
+    bar.set_facecolor(style["color"])
+    bar.set_hatch(style["hatch"])
+    bar.set_y(row["top"])
+    bar.set_height(row["thickness"])
+    bar.set_x(0)
+    bar.set_width(col_width)
+
+# Switch to continuous depth axis
+ax.set_ylim(total_depth, 0)
+ax.set_yticks([])
+
+# Formation labels to the right of each layer
+for _, row in df.iterrows():
+    ax.text(
+        col_width + 0.05,
+        row["mid_depth"],
+        row["formation"],
+        fontsize=15,
+        fontweight="medium",
+        va="center",
+        ha="left",
+        color="#2C2C2C",
+    )
+
+# Mark major unconformities with wavy lines for data storytelling
+unconformities = [(100, "Cretaceous–Jurassic"), (140, "Jurassic–Triassic"), (162, "Triassic–Permian")]
+
+for depth, label in unconformities:
+    x_wave = np.linspace(0, col_width, 80)
+    y_wave = depth + 0.8 * np.sin(x_wave * 40)
+    ax.plot(x_wave, y_wave, color="#CC3333", linewidth=2.5, zorder=5)
+    # Place unconformity labels above the wavy line, inside column
+    ax.text(
+        col_width / 2,
+        depth - 2.0,
+        label,
+        fontsize=10,
+        fontweight="bold",
+        va="bottom",
+        ha="center",
+        color="#CC3333",
+        fontstyle="italic",
+        zorder=6,
+        bbox={"facecolor": "white", "alpha": 0.85, "edgecolor": "none", "pad": 1.5},
+    )
+
+# Age labels on the left panel
+age_positions = {}
+for _, row in df.iterrows():
+    age = row["age"]
+    if age not in age_positions:
+        age_positions[age] = {"top": row["top"], "bottom": row["bottom"]}
+    age_positions[age]["top"] = min(age_positions[age]["top"], row["top"])
+    age_positions[age]["bottom"] = max(age_positions[age]["bottom"], row["bottom"])
+
+ax_age.set_xlim(0, 1)
+ax_age.set_ylim(total_depth, 0)
+ax.set_xlim(-0.02, 1.20)
+
+for age, pos in age_positions.items():
+    mid_y = (pos["top"] + pos["bottom"]) / 2
+    bg = age_bg_colors[age]
+
+    # Subtle background band across both panels
+    ax_age.axhspan(pos["top"], pos["bottom"], color=bg, zorder=0)
+    ax.axhspan(pos["top"], pos["bottom"], color=bg, zorder=0)
+
+    # Bracket lines
+    ax_age.plot(
+        [0.85, 0.85], [pos["top"] + 1, pos["bottom"] - 1], color="#555555", linewidth=2.5, solid_capstyle="butt"
+    )
+    ax_age.plot([0.80, 0.90], [pos["top"] + 1, pos["top"] + 1], color="#555555", linewidth=2)
+    ax_age.plot([0.80, 0.90], [pos["bottom"] - 1, pos["bottom"] - 1], color="#555555", linewidth=2)
+
+    # Age text
+    ax_age.text(
+        0.35,
+        mid_y,
+        age.replace(" ", "\n"),
+        fontsize=15,
+        fontweight="bold",
+        va="center",
+        ha="center",
+        fontstyle="italic",
+        color="#333333",
+    )
+
+# Style age axis
+ax_age.set_ylabel("Depth (m)", fontsize=20, labelpad=10)
+ax_age.tick_params(axis="y", labelsize=16)
+ax_age.set_yticks(np.arange(0, total_depth + 1, 20))
+ax_age.set_xticks([])
+sns.despine(ax=ax_age, top=True, right=True, bottom=True)
+
+ax.set_xticks([])
+ax.set_xlabel("")
+ax.set_ylabel("")
+ax.tick_params(axis="y", left=False, labelleft=False)
+sns.despine(ax=ax, left=True, bottom=True, top=True, right=True)
+
+# Right panel: seaborn stripplot showing layer thicknesses by lithology
+# Uses distinctive seaborn categorical visualization (strip plot with jitter)
+lith_order = [s["label"] for s in lithology_styles.values()]
+strip_palette = {s["label"]: s["color"] for s in lithology_styles.values()}
+sns.stripplot(
+    data=thickness_df,
+    x="thickness",
+    y="lithology",
+    ax=ax_thick,
+    palette=strip_palette,
+    hue="lithology",
+    order=lith_order,
+    size=14,
+    marker="D",
+    edgecolor="black",
+    linewidth=1.0,
+    jitter=False,
+    legend=False,
+)
+ax_thick.set_xlabel("Thickness (m)", fontsize=16)
+ax_thick.set_ylabel("")
+ax_thick.tick_params(axis="both", labelsize=13)
+ax_thick.set_title("Layer Thickness", fontsize=16, fontweight="medium", pad=8)
+ax_thick.xaxis.grid(True, alpha=0.3, linewidth=0.8)
+sns.despine(ax=ax_thick, top=True, right=True)
+
+# Lithology legend on the thickness panel (avoids overlapping column labels)
+legend_handles = [
+    mpatches.Patch(facecolor=style["color"], edgecolor="black", hatch=style["hatch"], label=style["label"])
+    for style in lithology_styles.values()
+]
+
+ax_thick.legend(
+    handles=legend_handles,
+    loc="lower right",
+    fontsize=12,
+    framealpha=0.95,
+    title="Lithology",
+    title_fontsize=14,
+    edgecolor="#CCCCCC",
+    fancybox=True,
+)
+
+# Title
+fig.suptitle("column-stratigraphic · seaborn · pyplots.ai", fontsize=24, fontweight="medium", y=0.97)
+
+plt.subplots_adjust(wspace=0.08)
+plt.tight_layout(rect=[0, 0, 1, 0.95])
+
+# Save
+plt.savefig("plot.png", dpi=300, bbox_inches="tight")