Ignore inaccessible roads, certain service roads, and areas (fixes #116)

roads_import.lua

@@ -56,6 +56,12 @@ local ADMIN_LEVEL_MAX = 8
 local ONEWAY_YES = {"yes", "true", "1"}
 local ONEWAY_REVERSE = {"reverse", "-1"}
 
+-- https://wiki.openstreetmap.org/wiki/Tag:highway=service
+local IGNORED_SERVICE_TYPES = {"parking_aisle", "driveway", "emergency_access", "drive-through"}
+
+-- https://taginfo.openstreetmap.org/keys/access#values
+local IGNORED_ACCESS_TYPES = {"no", "private", "permit", "official", "service", "emergency"}
+
 local roads = osm2pgsql.define_way_table('road', {
   { column = 'zone', type = 'text', sql_type="zone_type" },
   { column = 'directionality', type = 'int' },
@@ -73,8 +79,21 @@ local regions = osm2pgsql.define_relation_table('region', {
 
 
 function osm2pgsql.process_way(object)
-  if object.tags.highway and contains(HIGHWAY_TYPES, object.tags.highway) then
   local tags = object.tags
+
+  -- only import certain highway ways, i.e. roads and pathways
+  if not tags.highway then return end
+  if not contains(HIGHWAY_TYPES, tags.highway) then return end
+
+  -- do not import areas (plazas etc.)
+  if tags.area == "yes" then return end
+
+  -- ignore certain service roads
+  if contains(IGNORED_SERVICE_TYPES, tags.service) then return end
+
+  -- ignore disallowed roads (often tram tracks and similar)
+  if contains(IGNORED_ACCESS_TYPES, tags.access) then return end
+
   local zone = nil
 
   if tags["zone:traffic"] then
@@ -121,7 +140,6 @@ function osm2pgsql.process_way(object)
     directionality = directionality,
     oneway = oneway,
   })
-  end
 end
 
 function osm2pgsql.process_relation(object)