add layer_building etldoc comments

gen_etl_graph_building.sh

@@ -0,0 +1,21 @@
+
+
+
+
+DOT=building.dot
+
+echo "digraph G
+{    
+rankdir=LR;
+" > $DOT
+
+cat ./layers/building/mapping.yaml    | grep    "# etldoc:" |  sed 's/# etldoc://g'  >>$DOT
+cat ./layers/building/building.sql    | grep "\-\- etldoc:" |  sed 's/-- etldoc://g' >>$DOT
+
+echo "
+}
+" >> $DOT
+
+cat $DOT
+
+dot -Tpng $DOT > layer_building_etl.png

layers/building/building.sql

@@ -1,11 +1,20 @@
+
+
+
+-- etldoc: layer_building[shape=record fillcolor=lightpink, style="rounded,filled",  
+-- etldoc:     label="layer_building | <z13> z13 | <z14_> z14_ " ] ;
+
 CREATE OR REPLACE FUNCTION layer_building(bbox geometry, zoom_level int)
 RETURNS TABLE(geom geometry, osm_id bigint, render_height numeric) AS $$
     SELECT geometry, osm_id,
     least(greatest(3, COALESCE(height, levels*3.66,5)),400)^.7::int AS render_height
     FROM (
+
+        -- etldoc: osm_building_polygon_gen1 -> layer_building:z13
         SELECT osm_id, geometry, height, levels FROM osm_building_polygon_gen1
         WHERE zoom_level = 13 AND geometry && bbox AND area > 1400
         UNION ALL
+        -- etldoc: osm_building_polygon -> layer_building:z14_
         SELECT osm_id, geometry, height, levels FROM osm_building_polygon
         WHERE zoom_level >= 14 AND geometry && bbox
     ) AS zoom_levels

layers/building/mapping.yaml

@@ -1,9 +1,14 @@
 generalized_tables:
+
+  # etldoc: imposm3 -> osm_building_polygon_gen1
   building_polygon_gen1:
     source: building_polygon
     sql_filter: area>1400.0
     tolerance: 10.0
+
 tables:
+
+  # etldoc: imposm3 -> osm_building_polygon
   building_polygon:
     fields:
     - name: osm_id