Index: trunk/resources/data/validator/geometry.mapcss
===================================================================
--- trunk/resources/data/validator/geometry.mapcss	(revision 18914)
+++ trunk/resources/data/validator/geometry.mapcss	(revision 18921)
@@ -199,5 +199,8 @@
 
 /* Overlapping areas (spatial test) */
-area[natural =~ /^(water|wetland|coastline)$/], area[waterway=riverbank], area[landuse=reservoir] {
+area[natural =~ /^(water|wetland)$/],
+area[natural=coastline]:clockwise,
+area[waterway=riverbank],
+area[landuse=reservoir] {
   set water_area;
 }
@@ -211,8 +214,10 @@
 
 /* Water area inside water area (spatial test) */
-area:closed[natural =~ /^(water|wetland|coastline)$/] ⊆  area:closed.water_area,
+area:closed[natural =~ /^(water|wetland)$/]           ⊆  area:closed.water_area,
+area:closed[natural=coastline]:clockwise              ⊆  area:closed.water_area,
 area:closed[waterway=riverbank]                       ⊆  area:closed.water_area,
 area:closed[landuse=reservoir]                        ⊆  area:closed.water_area,
-area:closed[natural =~ /^(water|wetland|coastline)$/] ⊇  area:closed.water_area,
+area:closed[natural =~ /^(water|wetland)$/]           ⊇  area:closed.water_area,
+area:closed[natural=coastline]:clockwise              ⊇  area:closed.water_area,
 area:closed[waterway=riverbank]                       ⊇  area:closed.water_area,
 area:closed[landuse=reservoir]                        ⊇  area:closed.water_area {