Update road sort key values

TileStache/Goodies/VecTiles/transform.py

@@ -291,89 +291,82 @@ def road_classifier(shape, properties, fid, zoom):
 def road_sort_key(shape, properties, fid, zoom):
     # Note! parse_layer_as_float must be run before this filter.
 
-    # Calculated sort value is in the range 0 to 39
-    sort_val = 0
+    floor = 300
+    ceiling = 447
+    sort_val = floor
 
-    # Base layer range is 15 to 24
     highway = properties.get('highway', '')
     railway = properties.get('railway', '')
     aeroway = properties.get('aeroway', '')
     aerialway = properties.get('aerialway', '')
-    service = properties.get('service')
+    service = properties.get('service', '')
+    ne_type = properties.get('type', '')
 
-    is_railway = railway in ('rail', 'tram', 'light_rail', 'narrow_guage', 'monorail')
+    is_railway = railway in (
+        'rail', 'tram', 'light_rail', 'narrow_guage', 'monorail')
 
-    if highway == 'motorway':
-        sort_val += 24
+    if (highway == 'motorway' or
+            ne_type in ('Major Highway', 'Beltway', 'Bypass')):
+        sort_val += 81
     elif is_railway:
-        sort_val += 23
-    elif highway == 'trunk':
-        sort_val += 22
-    elif highway == 'primary':
-        sort_val += 21
+        sort_val += 80
+    elif highway == 'trunk' or ne_type == 'Secondary Highway':
+        sort_val += 79
+    elif highway == 'primary' or ne_type == 'Road':
+        sort_val += 78
     elif highway == 'secondary' or aeroway == 'runway':
-        sort_val += 20
-    elif highway == 'tertiary' or aeroway == 'taxiway':
-        sort_val += 19
+        sort_val += 77
+    elif highway == 'tertiary' or aeroway == 'taxiway' or ne_type == 'Track':
+        sort_val += 76
     elif highway.endswith('_link'):
-        sort_val += 18
-    elif highway in ('residential', 'unclassified', 'road', 'living_street'):
-        sort_val += 17
-    elif highway in ('unclassified', 'service', 'minor'):
-        sort_val += 16
+        sort_val += 75
+    elif (highway in ('residential', 'unclassified', 'road', 'living_street')
+          or ne_type == 'Unknown'):
+        sort_val += 60
+    elif highway in ('service', 'minor'):
+        sort_val += 58
     elif aerialway in ('gondola', 'cable_car'):
-        sort_val += 27
+        sort_val += 92
     elif aerialway == 'chair_lift':
-        sort_val += 26
-    elif aerialway != '':
-        sort_val += 25
+        sort_val += 91
+    elif aerialway:
+        sort_val += 90
     else:
-        sort_val += 15
+        sort_val += 55
 
-    if is_railway and service is not None:
+    if is_railway and service:
         if service in ('spur', 'siding'):
             # make sort val more like residential, unclassified which
             # also come in at zoom 12
-            sort_val -= 6
+            sort_val -= 19
         elif service == 'yard':
-            sort_val -= 7
+            sort_val -= 21
         else:
-            sort_val -= 8
+            sort_val -= 23
 
-    if highway == 'service' and service is not None:
+    if highway == 'service' and service:
         # sort alley, driveway, etc... under service
-        sort_val -= 1
+        sort_val -= 2
 
     if zoom >= 15:
-        # Bridges and tunnels add +/- 10
         bridge = properties.get('bridge')
         tunnel = properties.get('tunnel')
-        if bridge in ('yes', 'true'):
-            sort_val += 10
+        if bridge in ('yes', 'true') or aerialway:
+            sort_val += 50
         elif (tunnel in ('yes', 'true') or
               (railway == 'subway' and tunnel not in ('no', 'false'))):
-            sort_val -= 10
-
-        # Keep aerialways above (almost) everything else, including bridges,
-        # but make sure it doesn't go beyond the 0-34 range. (still need to
-        # leave space for explicit layer).
-        if aerialway != '':
-            sort_val = min(34, sort_val + 10)
+            sort_val -= 50
 
         # Explicit layer is clipped to [-5, 5] range. Note that
         # the layer, if present, will be a Float due to the
         # parse_layer_as_float filter.
         layer = properties.get('layer')
         if layer is not None:
             layer = max(min(layer, 5), -5)
-            # The range of values from above is [5, 34]
-            # For positive layer values, we want the range to be:
-            # [34, 39]
             if layer > 0:
-                sort_val = int(layer + 34)
-            # For negative layer values, [0, 5]
+                sort_val = int(layer + ceiling - 5)
             elif layer < 0:
-                sort_val = int(layer + 5)
+                sort_val = int(layer + floor + 5)
 
     properties['sort_key'] = sort_val