Do not generate roads and events for tiles at low zoom levels

tile-generator/layers/obs_events/layer.sql

@@ -15,6 +15,7 @@ RETURNS TABLE(event_id bigint, geometry geometry, distance_overtaker float, dist
     FULL OUTER JOIN road ON road.way_id = overtaking_event.way_id
     JOIN track on track.id = overtaking_event.track_id
     WHERE ST_Transform(overtaking_event.geometry, 3857) && bbox
+      AND zoom_level >= 10
       AND (user_id is NULL OR user_id = track.author_id)
       AND time BETWEEN COALESCE(min_time, '1900-01-01'::timestamp) AND COALESCE(max_time, '2100-01-01'::timestamp);
 

tile-generator/layers/obs_roads/layer.sql

@@ -67,6 +67,7 @@ RETURNS TABLE(
     ) e on (e.way_id = road.way_id and (road.directionality != 0 or e.direction_reversed = r.rev))
 
     WHERE road.geometry && bbox
+      AND zoom_level >= 10
     GROUP BY
       road.name,
       road.way_id,