text: drop materialized view if exists details_poly;
  create materialized view details_poly (
    gid,
    wkb,
    geom,
    kind
  ) as
  SELECT
    osm_id,
    ST_AsBinary(way),
    way,
    coalesce(leisure, landcover) AS kind
  FROM
    planet_osm_polygon
  WHERE
    leisure in ('stadium', 'pitch') or
    landcover in ('grass', 'trees');
  