Initial GeoIntel V1 foundation

backend/app/services/detection_georeferencing.py

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+from __future__ import annotations
+
+from typing import Any
+
+from pyproj import Transformer
+from shapely.geometry import Polygon
+
+from app.core.errors import AppError
+
+
+def pixel_bbox_to_epsg4326_polygon(bbox: list[float], tile: dict[str, Any], crs: str | None = None) -> Polygon:
+    if len(bbox) != 4:
+        raise AppError(code="DETECTION_INVALID_BBOX", message="YOLO detection bbox must contain four pixel coordinates", status_code=422)
+
+    x_min, y_min, x_max, y_max = [float(value) for value in bbox]
+    if x_max <= x_min or y_max <= y_min:
+        raise AppError(code="DETECTION_INVALID_BBOX", message="YOLO detection bbox must have positive width and height", status_code=422)
+
+    transform = tile.get("transform")
+    if isinstance(transform, list) and len(transform) >= 6:
+        corners = [
+            _apply_gdal_transform(transform, x_min, y_min),
+            _apply_gdal_transform(transform, x_max, y_min),
+            _apply_gdal_transform(transform, x_max, y_max),
+            _apply_gdal_transform(transform, x_min, y_max),
+            _apply_gdal_transform(transform, x_min, y_min),
+        ]
+    else:
+        corners = _corners_from_bounds(bbox=[x_min, y_min, x_max, y_max], tile=tile)
+
+    source_crs = crs or tile.get("crs") or tile.get("source_crs") or "EPSG:4326"
+    if str(source_crs).upper() not in {"EPSG:4326", "4326"}:
+        transformer = Transformer.from_crs(source_crs, "EPSG:4326", always_xy=True)
+        corners = [transformer.transform(x, y) for x, y in corners]
+
+    polygon = Polygon(corners)
+    if polygon.is_empty or not polygon.is_valid:
+        raise AppError(code="DETECTION_INVALID_GEOMETRY", message="Georeferenced detection geometry is invalid", status_code=422)
+    return polygon
+
+
+def _apply_gdal_transform(transform: list[float], x: float, y: float) -> tuple[float, float]:
+    c, a, b, f, d, e = [float(value) for value in transform[:6]]
+    return (a * x + b * y + c, d * x + e * y + f)
+
+
+def _corners_from_bounds(bbox: list[float], tile: dict[str, Any]) -> list[tuple[float, float]]:
+    bounds = tile.get("bounds")
+    pixel_window = tile.get("pixel_window")
+    if not (isinstance(bounds, list) and len(bounds) == 4 and isinstance(pixel_window, list) and len(pixel_window) == 4):
+        raise AppError(
+            code="DETECTION_TILE_MANIFEST_INVALID",
+            message="Tile manifest entries require transform or bounds plus pixel_window for georeferencing",
+            status_code=422,
+        )
+    x_min, y_min, x_max, y_max = bbox
+    left, bottom, right, top = [float(value) for value in bounds]
+    _, _, width, height = [float(value) for value in pixel_window]
+    if width <= 0 or height <= 0:
+        raise AppError(code="DETECTION_TILE_MANIFEST_INVALID", message="Tile pixel_window must have positive size", status_code=422)
+
+    def project(px: float, py: float) -> tuple[float, float]:
+        x = left + (px / width) * (right - left)
+        y = top - (py / height) * (top - bottom)
+        return (x, y)
+
+    return [
+        project(x_min, y_min),
+        project(x_max, y_min),
+        project(x_max, y_max),
+        project(x_min, y_max),
+        project(x_min, y_min),
+    ]