Analyze Ground Zero shoreline requirements

2026-05-14 05:53:53 -07:00
parent e9896cdce1
commit fcb3d18b0c
4 changed files with 242 additions and 2 deletions
@@ -0,0 +1,116 @@
+#!/usr/bin/env python3
+"""Analyze first-pass water and shoreline applicability for the Ground Zero tile."""
+
+from __future__ import annotations
+
+import json
+from datetime import datetime, timezone
+from pathlib import Path
+
+import numpy as np
+from osgeo import gdal
+
+gdal.UseExceptions()
+
+
+PROJECT_ROOT = Path(__file__).resolve().parents[1]
+TILE_ID = "gz_us_ca_pacifica_utm10n_e544_n4160"
+DEM_PATH = PROJECT_ROOT / "Data" / "Terrain" / "Extracted" / TILE_ID / f"{TILE_ID}_1m_dem_subset.tif"
+OUTPUT_DIR = PROJECT_ROOT / "Data" / "Terrain" / "Analysis" / TILE_ID
+OUTPUT_PATH = OUTPUT_DIR / f"{TILE_ID}_water_shoreline_analysis.json"
+
+SEA_LEVEL_M = 0.0
+SHORELINE_BUFFER_M = 2.0
+LOW_COASTAL_BUFFER_M = 5.0
+
+
+def summarize_edge(values: np.ndarray) -> dict[str, float | int]:
+    finite = values[np.isfinite(values)]
+    return {
+        "sample_count": int(finite.size),
+        "min_elevation_m": float(np.min(finite)) if finite.size else None,
+        "max_elevation_m": float(np.max(finite)) if finite.size else None,
+        "mean_elevation_m": float(np.mean(finite)) if finite.size else None,
+        "sea_level_or_below_samples": int(np.count_nonzero(finite <= SEA_LEVEL_M)),
+        "near_sea_level_samples": int(np.count_nonzero(finite <= SHORELINE_BUFFER_M)),
+        "low_coastal_samples": int(np.count_nonzero(finite <= LOW_COASTAL_BUFFER_M)),
+    }
+
+
+def main() -> None:
+    dataset = gdal.Open(str(DEM_PATH), gdal.GA_ReadOnly)
+    if dataset is None:
+        raise RuntimeError(f"Could not open DEM: {DEM_PATH}")
+
+    band = dataset.GetRasterBand(1)
+    data = band.ReadAsArray().astype(float)
+    nodata = band.GetNoDataValue()
+    if nodata is not None:
+        data[data == nodata] = np.nan
+
+    finite = data[np.isfinite(data)]
+    if finite.size == 0:
+        raise RuntimeError(f"DEM has no finite elevation samples: {DEM_PATH}")
+
+    total_samples = int(finite.size)
+    sea_or_below = int(np.count_nonzero(finite <= SEA_LEVEL_M))
+    near_sea = int(np.count_nonzero(finite <= SHORELINE_BUFFER_M))
+    low_coastal = int(np.count_nonzero(finite <= LOW_COASTAL_BUFFER_M))
+
+    edge_width = 10
+    edges = {
+        "north": summarize_edge(data[:edge_width, :].reshape(-1)),
+        "south": summarize_edge(data[-edge_width:, :].reshape(-1)),
+        "west": summarize_edge(data[:, :edge_width].reshape(-1)),
+        "east": summarize_edge(data[:, -edge_width:].reshape(-1)),
+    }
+
+    has_open_water = sea_or_below > 0
+    has_shoreline = near_sea > 0
+
+    result = {
+        "schema_version": 1,
+        "tile_id": TILE_ID,
+        "generated_at_utc": datetime.now(timezone.utc).replace(microsecond=0).isoformat().replace("+00:00", "Z"),
+        "source_dem": str(DEM_PATH.relative_to(PROJECT_ROOT)),
+        "thresholds": {
+            "sea_level_m": SEA_LEVEL_M,
+            "shoreline_buffer_m": SHORELINE_BUFFER_M,
+            "low_coastal_buffer_m": LOW_COASTAL_BUFFER_M,
+        },
+        "elevation_summary": {
+            "sample_count": total_samples,
+            "min_elevation_m": float(np.min(finite)),
+            "max_elevation_m": float(np.max(finite)),
+            "mean_elevation_m": float(np.mean(finite)),
+            "sea_level_or_below_samples": sea_or_below,
+            "near_sea_level_samples": near_sea,
+            "low_coastal_samples": low_coastal,
+            "sea_level_or_below_percent": sea_or_below / total_samples * 100.0,
+            "near_sea_level_percent": near_sea / total_samples * 100.0,
+            "low_coastal_percent": low_coastal / total_samples * 100.0,
+        },
+        "edge_summary": edges,
+        "classification": {
+            "contains_open_water": has_open_water,
+            "contains_shoreline": has_shoreline,
+            "water_depth_required_for_mvp_tile": False,
+            "shoreline_mesh_required_for_mvp_tile": False,
+            "freshwater_source_required_for_gameplay": True,
+            "recommended_first_pass": "No ocean/shoreline actor required inside the current Ground Zero tile. Add a small freshwater source for gameplay separately, and defer ocean/bathymetry work to west/southwest neighbor coastal tiles.",
+        },
+        "notes": [
+            "This analysis uses the extracted 1-meter USGS DEM for the selected 1 km tile.",
+            "The selected Ground Zero tile is coastal-influenced but the DEM minimum is above sea level.",
+            "Ocean depth/bathymetry remains required for adjacent coastal/ocean tiles before multi-tile expansion.",
+        ],
+    }
+
+    OUTPUT_DIR.mkdir(parents=True, exist_ok=True)
+    OUTPUT_PATH.write_text(json.dumps(result, indent=2) + "\n", encoding="utf-8")
+    print(f"Wrote {OUTPUT_PATH.relative_to(PROJECT_ROOT)}")
+    print(json.dumps(result["classification"], indent=2))
+
+
+if __name__ == "__main__":
+    main()