diff --git a/src/komap.py b/src/komap.py
index 199b451..53ad2b2 100644
--- a/src/komap.py
+++ b/src/komap.py
@@ -643,9 +643,9 @@ if options.renderer == "mapnik":
             elif layer_type == "line" and there_are_dashed_lines:
               itags = ", ".join(itags)
               oitags = '"'+ "\", \"".join(oitags) +'"'
-              sqlz = """select %s, ST_LineMerge((ST_SnapToGrid(ST_Union(way),%s))) as way from (SELECT * from planet_osm_line where way && !bbox! and (%s)) as tex
+              sqlz = """select %s, ST_LineMerge(ST_Union(way)) as way from (SELECT %s, ST_SnapToGrid(way, %s) as way from planet_osm_line where way && !bbox! and (%s)) as tex
               group by %s
-              """%(itags,pixel_size_at_zoom(zoom, 0.5),sql,oitags)
+              """%(itags, oitags,pixel_size_at_zoom(zoom, 0.7),sql,oitags)
               mfile.write(xml_layer("postgis-process", layer_type, itags, sqlz, zoom=zoom ))
             else:
               if roads: