lgtm

pipeline/download/naptan.py

@@ -12,6 +12,7 @@ import polars as pl
 
 NAPTAN_CSV_URL = "https://naptan.api.dft.gov.uk/v1/access-nodes?dataFormat=csv"
 TUBE_STATION_CATEGORY = "Tube station"
+DLR_STATION_CATEGORY = "DLR station"
 TRAM_METRO_CATEGORY = "Tram & Metro stop"
 TUBE_STATION_MERGE_RADIUS_DEGREES = 0.01
 
@@ -24,6 +25,13 @@ TUBE_STATION_MERGE_RADIUS_DEGREES = 0.01
 # WM Metro, Blackpool Tramway, heritage railways, ...).
 LONDON_UNDERGROUND_ATCO_PATTERN = r"(?i)^\d{3}[0G]ZZLU"
 
+# The Docklands Light Railway uses the analogous "ZZDL" system code (e.g.
+# "9400ZZDLBEC" for Beckton). Like ZZLU it is unique to one network, so a
+# TMU/MET stop carrying a ZZDL code is reclassified from the tram/metro family
+# to its own "DLR station" category — restoring DLR to the train/tube station
+# list and giving it the DLR roundel rather than a generic tram icon.
+LONDON_DLR_ATCO_PATTERN = r"(?i)^\d{3}[0G]ZZDL"
+
 
 STOP_TYPES = {
     "AIR": "Airport",
@@ -48,10 +56,11 @@ STOP_TYPES = {
     "TXR": "Taxi rank",
     # Tram/Metro/Underground: TMU is an entrance node, MET the station access
     # area. Both start as "Tram & Metro stop"; merged stations whose ATCO codes
-    # mark them as London Underground (ZZLU) are reclassified to "Tube station"
-    # after dedup (see _deduplicate_station_areas). Heritage railways (RHDR,
-    # Severn Valley, ...) are TMU/MET in NaPTAN with no machine-readable
-    # "heritage" flag, so they remain in "Tram & Metro stop".
+    # mark them as London Underground (ZZLU) or Docklands Light Railway (ZZDL)
+    # are reclassified to "Tube station" / "DLR station" after dedup (see
+    # _deduplicate_station_areas). Heritage railways (RHDR, Severn Valley, ...)
+    # are TMU/MET in NaPTAN with no machine-readable "heritage" flag, so they
+    # remain in "Tram & Metro stop".
     "TMU": TRAM_METRO_CATEGORY,
     "MET": TRAM_METRO_CATEGORY,
 }
@@ -68,6 +77,7 @@ ENTRANCE_STOP_TYPES = {"RSE", "FTD", "TMU", "BCE"}
 STATION_MERGE_CATEGORIES = {
     TRAM_METRO_CATEGORY,
     TUBE_STATION_CATEGORY,
+    DLR_STATION_CATEGORY,
     "Rail station",
     "Ferry",
     "Bus station",
@@ -266,6 +276,7 @@ class StationAccumulator:
     lng_sum: float
     entrance: bool = False
     is_lu: bool = False
+    is_dlr: bool = False
     count: int = 1
     qualifier: str = ""
 
@@ -292,6 +303,7 @@ class StationAccumulator:
         self.lng_sum += float(row["lng"])
         self.count += 1
         self.is_lu = self.is_lu or bool(row.get("is_lu"))
+        self.is_dlr = self.is_dlr or bool(row.get("is_dlr"))
 
         name = str(row["name"] or "")
         row_qualifier = station_name_qualifier(name)
@@ -318,12 +330,19 @@ class StationAccumulator:
 
     @property
     def output_category(self) -> str:
-        # A merged tram/metro station is a genuine Tube station when ANY of its
-        # constituent nodes carries a London Underground ATCO code. Checking
-        # the whole group (not just the winning node) matters because LU
-        # entrance nodes often carry non-ZZLU codes (e.g. 4900VICT...).
+        # A merged tram/metro station is a genuine Tube/DLR station when ANY of
+        # its constituent nodes carries the matching ATCO system code. Checking
+        # the whole group (not just the winning node) matters because LU/DLR
+        # entrance nodes often carry non-ZZLU/ZZDL codes (e.g. 4900VICT...).
+        # A single node is never both (ZZLU vs ZZDL), but a co-located
+        # interchange (Bank, Stratford, Canning Town, West Ham) merges its LU
+        # and DLR halves into one group carrying both flags; Tube is checked
+        # first so these resolve to "Tube station" — their primary identity —
+        # leaving "DLR station" for the DLR-only stops the fix targets.
         if self.category == TRAM_METRO_CATEGORY and self.is_lu:
             return TUBE_STATION_CATEGORY
+        if self.category == TRAM_METRO_CATEGORY and self.is_dlr:
+            return DLR_STATION_CATEGORY
         return self.category
 
 
@@ -336,6 +355,7 @@ def _station_from_row(row: dict[str, object]) -> StationAccumulator:
         lng_sum=float(row["lng"]),
         entrance=bool(row.get("entrance")),
         is_lu=bool(row.get("is_lu")),
+        is_dlr=bool(row.get("is_dlr")),
         qualifier=station_name_qualifier(str(row["name"] or "")),
     )
 
@@ -423,7 +443,8 @@ def deduplicate_naptan(df: pl.DataFrame) -> pl.DataFrame:
     station by normalized name + area, with the primary station/terminal node
     (e.g. RLY, FER, MET, BST) winning over an entrance node (RSE, FTD, TMU,
     BCE). Merged tram/metro stations with a London Underground ATCO code in
-    the group become "Tube station". Other stops are deduplicated by exact
+    the group become "Tube station"; those with a Docklands Light Railway code
+    become "DLR station". Other stops are deduplicated by exact
     name+category+locality.
     """
     station = df.filter(pl.col("category").is_in(list(STATION_MERGE_CATEGORIES)))
@@ -490,6 +511,10 @@ def download_naptan(output: Path) -> None:
         .str.contains(LONDON_UNDERGROUND_ATCO_PATTERN)
         .fill_null(False)
         .alias("is_lu"),
+        pl.col("ATCOCode")
+        .str.contains(LONDON_DLR_ATCO_PATTERN)
+        .fill_null(False)
+        .alias("is_dlr"),
     )
 
     before = len(df)