diff --git a/gen_etl_graph_landcover.sh b/gen_etl_graph_landcover.sh
new file mode 100755
index 00000000..008b0ce7
--- /dev/null
+++ b/gen_etl_graph_landcover.sh
@@ -0,0 +1,19 @@
+
+
+DOT=landcover.dot
+
+echo "digraph G
+{    
+rankdir=LR;
+" > $DOT
+
+cat ./layers/landcover/mapping.yaml   | grep    "# etldoc:" |  sed 's/# etldoc://g'  >>$DOT
+cat ./layers/landcover/landcover.sql  | grep "\-\- etldoc:" |  sed 's/-- etldoc://g' >>$DOT
+
+echo "
+}
+" >> $DOT
+
+cat $DOT
+
+dot -Tpng $DOT > layer_landcover_etl.png
diff --git a/layers/landcover/landcover.sql b/layers/landcover/landcover.sql
index ca84f935..a3549240 100644
--- a/layers/landcover/landcover.sql
+++ b/layers/landcover/landcover.sql
@@ -20,83 +20,108 @@ CREATE OR REPLACE FUNCTION landcover_class(landuse VARCHAR, "natural" VARCHAR, w
     END;
 $$ LANGUAGE SQL IMMUTABLE;
 
+-- etldoc: ne_110m_glaciated_areas ->  landcover_z0 
 CREATE OR REPLACE VIEW landcover_z0 AS (
     SELECT NULL::int AS osm_id, geom AS geometry, NULL AS landuse, 'glacier' AS "natural", NULL::text AS wetland FROM ne_110m_glaciated_areas
 );
 
 CREATE OR REPLACE VIEW landcover_z2 AS (
+    -- etldoc: ne_50m_glaciated_areas ->  landcover_z2 
     SELECT NULL::bigint AS osm_id, geom AS geometry, NULL::text AS landuse, 'glacier' AS "natural", NULL::text AS wetland FROM ne_50m_glaciated_areas
     UNION ALL
+    -- etldoc: ne_50m_antarctic_ice_shelves_polys ->  landcover_z2     
     SELECT NULL::bigint AS osm_id, geom AS geometry, NULL::text AS landuse, 'ice_shelf' AS "natural", NULL::text AS wetland FROM ne_50m_antarctic_ice_shelves_polys
 );
 
 CREATE OR REPLACE VIEW landcover_z5 AS (
+    -- etldoc: ne_10m_glaciated_areas ->  landcover_z5
     SELECT NULL::bigint AS osm_id, geom AS geometry, NULL::text AS landuse, 'glacier' AS "natural", NULL::text AS wetland FROM ne_10m_glaciated_areas
     UNION ALL
+    -- etldoc: ne_10m_antarctic_ice_shelves_polys ->  landcover_z5 
     SELECT NULL::bigint AS osm_id, geom AS geometry, NULL::text AS landuse, 'ice_shelf' AS "natural", NULL::text AS wetland FROM ne_10m_antarctic_ice_shelves_polys
 );
 
 CREATE OR REPLACE VIEW landcover_z8 AS (
+    -- etldoc: osm_landcover_polygon_gen5 ->  landcover_z8  
     SELECT osm_id, geometry, landuse, "natural", wetland FROM osm_landcover_polygon_gen5
 );
 
 CREATE OR REPLACE VIEW landcover_z9 AS (
+    -- etldoc: osm_landcover_polygon_gen4 ->  landcover_z9    
     SELECT osm_id, geometry, landuse, "natural", wetland FROM osm_landcover_polygon_gen4
 );
 
 CREATE OR REPLACE VIEW landcover_z10 AS (
+    -- etldoc: osm_landcover_polygon_gen3 ->  landcover_z10    
     SELECT osm_id, geometry, landuse, "natural", wetland FROM osm_landcover_polygon_gen3
 );
 
 CREATE OR REPLACE VIEW landcover_z11 AS (
+    -- etldoc: osm_landcover_polygon_gen2 ->  landcover_z11    
     SELECT osm_id, geometry, landuse, "natural", wetland FROM osm_landcover_polygon_gen2
 );
 
 CREATE OR REPLACE VIEW landcover_z12 AS (
+    -- etldoc: osm_landcover_polygon_gen1 ->  landcover_z12    
     SELECT osm_id, geometry, landuse, "natural", wetland FROM osm_landcover_polygon_gen1
 );
 
 CREATE OR REPLACE VIEW landcover_z13 AS (
+    -- etldoc: osm_landcover_polygon ->  landcover_z13
     SELECT osm_id, geometry, landuse, "natural", wetland FROM osm_landcover_polygon WHERE ST_Area(geometry) > 60000
 );
 
 CREATE OR REPLACE VIEW landcover_z14 AS (
+    -- etldoc: osm_landcover_polygon ->  landcover_z14    
     SELECT osm_id, geometry, landuse, "natural", wetland FROM osm_landcover_polygon
 );
 
+-- etldoc: layer_landcover[shape=record fillcolor=lightpink, style="rounded,filled",  
+-- etldoc:     label="layer_landcover | <z0> z0  | <z2_4> z2_4  | <z5_7> z5_7 | <z8> z8 |<z9> z9 |<z10> z10 |<z11> z11 |<z12> z12|<z13> z13|<z14_> z14_" ] ;
+
 CREATE OR REPLACE FUNCTION layer_landcover(bbox geometry, zoom_level int)
 RETURNS TABLE(osm_id bigint, geometry geometry, class text, subclass text) AS $$
     SELECT osm_id, geometry,
         landcover_class(landuse, "natural", wetland) AS class,
         COALESCE(NULLIF("natural", ''), NULLIF(landuse, ''), NULLIF('wetland', '')) AS subclass
         FROM (
+        -- etldoc:  landcover_z0 -> layer_landcover:z0
         SELECT * FROM landcover_z0
         WHERE zoom_level BETWEEN 0 AND 1 AND geometry && bbox
         UNION ALL
+        -- etldoc:  landcover_z2 -> layer_landcover:z2_4        
         SELECT * FROM landcover_z2
         WHERE zoom_level BETWEEN 2 AND 4 AND geometry && bbox
         UNION ALL
+        -- etldoc:  landcover_z5 -> layer_landcover:z5_7
         SELECT * FROM landcover_z5
         WHERE zoom_level BETWEEN 5 AND 7 AND geometry && bbox
         UNION ALL
+        -- etldoc:  landcover_z8 -> layer_landcover:z8
         SELECT osm_id, geometry, landuse, "natural", wetland
         FROM landcover_z8 WHERE zoom_level = 8 AND geometry && bbox
         UNION ALL
+        -- etldoc:  landcover_z9 -> layer_landcover:z9        
         SELECT osm_id, geometry, landuse, "natural", wetland
         FROM landcover_z9 WHERE zoom_level = 9 AND geometry && bbox
         UNION ALL
+        -- etldoc:  landcover_z10 -> layer_landcover:z10
         SELECT osm_id, geometry, landuse, "natural", wetland
         FROM landcover_z10 WHERE zoom_level = 10 AND geometry && bbox
         UNION ALL
+        -- etldoc:  landcover_z11 -> layer_landcover:z11        
         SELECT osm_id, geometry, landuse, "natural", wetland
         FROM landcover_z11 WHERE zoom_level = 11 AND geometry && bbox
         UNION ALL
+        -- etldoc:  landcover_z12 -> layer_landcover:z12        
         SELECT osm_id, geometry, landuse, "natural", wetland
         FROM landcover_z12 WHERE zoom_level = 12 AND geometry && bbox
         UNION ALL
+        -- etldoc:  landcover_z13 -> layer_landcover:z13        
         SELECT osm_id, ST_Simplify(geometry, 10) AS geometry, landuse, "natural", wetland
         FROM landcover_z13 WHERE zoom_level = 13 AND geometry && bbox
         UNION ALL
+        -- etldoc:  landcover_z14 -> layer_landcover:z14_        
         SELECT osm_id, geometry, landuse, "natural", wetland
         FROM landcover_z14 WHERE zoom_level >= 14 AND geometry && bbox
     ) AS zoom_levels;
diff --git a/layers/landcover/mapping.yaml b/layers/landcover/mapping.yaml
index 112cb75f..2ac87417 100644
--- a/layers/landcover/mapping.yaml
+++ b/layers/landcover/mapping.yaml
@@ -1,25 +1,38 @@
 generalized_tables:
+  
+  # etldoc: imposm3 -> osm_landcover_polygon_gen5
   landcover_polygon_gen5:
     source: landcover_polygon_gen4
     sql_filter: area>15000000
     tolerance: 300.0
+
+  # etldoc: imposm3 -> osm_landcover_polygon_gen4
   landcover_polygon_gen4:
     source: landcover_polygon_gen3
     sql_filter: area>4200000
     tolerance: 200.0
+
+  # etldoc: imposm3 -> osm_landcover_polygon_gen3  
   landcover_polygon_gen3:
     source: landcover_polygon_gen2
     sql_filter: area>1200000
     tolerance: 120.0
+
+  # etldoc: imposm3 -> osm_landcover_polygon_gen2  
   landcover_polygon_gen2:
     source: landcover_polygon_gen1
     sql_filter: area>480000
     tolerance: 80.0
+
+  # etldoc: imposm3 -> osm_landcover_polygon_gen1  
   landcover_polygon_gen1:
     source: landcover_polygon
     sql_filter: area>240000
     tolerance: 50.0
+
 tables:
+  
+  # etldoc: imposm3 -> osm_landcover_polygon 
   landcover_polygon:
     fields:
     - name: osm_id