Address PR feedback: simplify Hessen coordinate extraction

- Remove redundant URL validation (already in XPath selector)
- Add type annotation to _extract_coords_from_osm_url()
- Remove mlat/mlon and bbox fallbacks (never used)
- Remove link fallback (iframe always present with coordinates)
- Add example URL for placeholder coordinates (-1.0, -1.0)
- Replace broad Exception with specific ValueError/IndexError
- Update README with geolocation statistics (1,863/2,054 schools)

Analysis confirmed Hessen iframes always use 'marker' parameter format.
The mlat/mlon format only appears in links, which are not needed.

Author: tim

README.md

@@ -49,7 +49,7 @@ When available, we try to use the geolocations provided by the data publishers.
 | BB    | ✅ Yes                | WFS                                          |
 | HB    | ❌ No                 | -                                            |
 | HH    | ✅ Yes                | WFS                                          |
-| HE    | ⚠️  Partial (90.7%)    | Extracted from OSM iframes on detail pages   |
+| HE    | ⚠️  Partial (90.7%)    | Extracted from OSM on detail pages (1,863/2,054 schools). The 191 schools without coordinates include both schools with placeholder coordinates (-1.0, -1.0) that are filtered to null and schools with no map data at all. |
 | MV    | ❌ No                 | -                                            |
 | NI    | ❌ No                 | -                                            |
 | NW    | ✅ Yes                | Converted from EPSG:25832 in source CSV data |

jedeschule/spiders/hessen.py

@@ -53,34 +53,16 @@ def parse_list(self, response):
         for school in schools:
             yield scrapy.Request(school, callback=self.parse_details)
 
-    def _extract_coords_from_osm_url(self, url):
-        """Extract coordinates from OpenStreetMap URL query parameters"""
-        if not url or "openstreetmap.org" not in url:
-            return None, None
-
+    def _extract_coords_from_osm_url(self, url: str) -> tuple[float | None, float | None]:
+        """Extract coordinates from OpenStreetMap iframe URL marker parameter"""
         qs = parse_qs(urlparse(url).query)
 
-        # Try marker parameter first (most precise)
+        # Extract marker parameter (format: "latitude,longitude")
         if "marker" in qs and qs["marker"]:
             try:
                 lat_str, lon_str = qs["marker"][0].split(",", 1)
                 return float(lat_str), float(lon_str)
-            except Exception:
-                pass
-
-        # Try mlat/mlon parameters
-        if "mlat" in qs and "mlon" in qs:
-            try:
-                return float(qs["mlat"][0]), float(qs["mlon"][0])
-            except Exception:
-                pass
-
-        # Fallback: bbox center
-        if "bbox" in qs and qs["bbox"]:
-            try:
-                west, south, east, north = map(float, qs["bbox"][0].split(",", 3))
-                return (south + north) / 2.0, (west + east) / 2.0
-            except Exception:
+            except (ValueError, IndexError):
                 pass
 
         return None, None
@@ -125,21 +107,14 @@ def parse_details(self, response):
         # Extract school ID from URL query parameter
         school["id"] = response.request.url.split("=")[-1]
 
-        # Extract coordinates from OpenStreetMap iframe or link
+        # Extract coordinates from OpenStreetMap iframe
         latitude, longitude = None, None
-
-        # Try iframe first
         iframe_src = response.xpath('//iframe[contains(@src, "openstreetmap.org")]/@src').get()
         if iframe_src:
             latitude, longitude = self._extract_coords_from_osm_url(iframe_src)
 
-        # Fallback: try "Größere Karte" link
-        if latitude is None:
-            osm_link = response.xpath('//a[contains(@href, "openstreetmap.org")]/@href').get()
-            if osm_link:
-                latitude, longitude = self._extract_coords_from_osm_url(osm_link)
-
         # Filter out placeholder coordinates (-1.0, -1.0) used by Hessen DB for missing data
+        # Example: https://schul-db.bildung.hessen.de/schul_db.html/details/?school_no=9642
         if latitude == -1.0 and longitude == -1.0:
             latitude = None
             longitude = None