map now working

bincio/extract/simplify.py

@@ -25,6 +25,33 @@ def simplify_track(
     return [p for (p, _, _), keep in zip(gps_pts, mask) if keep]
 
 
+def preview_coords(
+    points: list[DataPoint],
+    max_points: int = 20,
+) -> list[list[float]] | None:
+    """Return a small list of [lat, lon] pairs for card thumbnail rendering.
+
+    Uses a coarser RDP pass, then subsamples to at most max_points.
+    Returns None if there is no GPS data.
+    """
+    gps = [(p.lat, p.lon) for p in points if p.lat is not None and p.lon is not None]
+    if len(gps) < 2:
+        return None
+
+    # Coarse RDP (larger epsilon = fewer points)
+    coords = [[lon, lat] for lat, lon in gps]
+    mask = rdp(coords, epsilon=0.001, return_mask=True)
+    reduced = [gps[i] for i, keep in enumerate(mask) if keep]
+
+    # Subsample if still too many
+    if len(reduced) > max_points:
+        step = len(reduced) / max_points
+        reduced = [reduced[int(i * step)] for i in range(max_points)]
+        reduced.append(gps[-1])  # always include the last point
+
+    return [[round(lat, 5), round(lon, 5)] for lat, lon in reduced]
+
+
 def build_geojson(
     points: list[DataPoint],
     activity_id: str,