diff --git a/Makefile b/Makefile
index eeebeb9e..3c9d841c 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-all: build/openmaptiles.tm2source/data.yml build/mapping.yaml build/tileset.sql layers/railway/README.md
+all: build/openmaptiles.tm2source/data.yml build/mapping.yaml build/tileset.sql layers/railway/README.md layers/boundary/README.md
 
 build/openmaptiles.tm2source/data.yml:
 	mkdir -p build/openmaptiles.tm2source && generate-tm2source openmaptiles.yaml --host="postgres" --port=5432 --database="openmaptiles" --user="openmaptiles" --password="openmaptiles" > build/openmaptiles.tm2source/data.yml
@@ -12,5 +12,8 @@ build/tileset.sql:
 layers/railway/README.md:
 	generate-doc layers/railway/railway.yaml --diagram layers/railway/mapping > layers/railway/README.md
 
+layers/boundary/README.md:
+	generate-doc layers/boundary/boundary.yaml --diagram layers/boundary/mapping > layers/boundary/README.md
+
 clean:
 	rm -f build/openmaptiles.tm2source/data.yml && rm -f build/mapping.yaml && rm -f build/tileset.sql && rm -f layers/**/README.md&& rm -f layers/**/*.png
diff --git a/layers/boundary/README.md b/layers/boundary/README.md
new file mode 100644
index 00000000..98e68275
--- /dev/null
+++ b/layers/boundary/README.md
@@ -0,0 +1,19 @@
+# boundary
+
+Contains administrative boundaries as linestrings (no maritime boundaries yet) as linestrings.
+Until z7 [Natural Earth data](http://www.naturalearthdata.com/downloads/10m-cultural-vectors/10m-admin-0-countries/)
+is used after which OSM boundaries ([`boundary=administrative`](http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dadministrative)) are present from z8 to z14.
+OSM data contains all [`admin_level`](http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dadministrative#admin_level)
+but for most styles it makes sense to just style `admin_level=2` and `admin_level=4`.
+
+## Fields
+
+- **admin_level**: OSM [admin_level](http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dadministrative#admin_level)
+indicating the level of importance of this boundary.
+At low zoom levels the Natural Earth boundaries are mapped to the equivalent admin levels.
+
+## Mapping
+
+![](mapping.png)
+
+
diff --git a/layers/boundary/boundary.sql b/layers/boundary/boundary.sql
index 1b29d197..1e77514c 100644
--- a/layers/boundary/boundary.sql
+++ b/layers/boundary/boundary.sql
@@ -1,114 +1,85 @@
-CREATE OR REPLACE FUNCTION boundary_class(featureclass VARCHAR) RETURNS VARCHAR
-AS $$
-BEGIN
-    RETURN CASE
-        WHEN featureclass ILIKE 'line of control%' THEN 'control'
-        WHEN featureclass ILIKE 'disputed%' THEN 'dispute'
-        WHEN featureclass ILIKE 'lease%' THEN 'lease'
-        WHEN featureclass ILIKE 'overlay%' THEN 'overlay'
-        ELSE 'boundary'
-    END;
-END;
-$$ LANGUAGE plpgsql IMMUTABLE;
-
 CREATE OR REPLACE VIEW boundary_z0 AS (
-    SELECT geom, 2 AS admin_level, scalerank,
-           boundary_class(featurecla) AS class
+    SELECT geom, 2 AS admin_level
     FROM ne_110m_admin_0_boundary_lines_land
 );
 
 CREATE OR REPLACE VIEW boundary_z1 AS (
-    SELECT geom, 2 AS admin_level, scalerank,
-           boundary_class(featurecla) AS class
+    SELECT geom, 2 AS admin_level
     FROM ne_50m_admin_0_boundary_lines_land
     UNION ALL
-    SELECT geom, 4 AS admin_level, scalerank,
-           boundary_class(featurecla) AS class
+    SELECT geom, 4 AS admin_level
     FROM ne_50m_admin_1_states_provinces_lines
     WHERE scalerank <= 2
 );
 
 CREATE OR REPLACE VIEW boundary_z3 AS (
-    SELECT geom, 2 AS admin_level, scalerank,
-           boundary_class(featurecla) AS class
+    SELECT geom, 2 AS admin_level
     FROM ne_50m_admin_0_boundary_lines_land
     UNION ALL
-    SELECT geom, 4 AS admin_level, scalerank,
-           boundary_class(featurecla) AS class
+    SELECT geom, 4 AS admin_level
     FROM ne_50m_admin_1_states_provinces_lines
 );
 
 CREATE OR REPLACE VIEW boundary_z4 AS (
-    SELECT geom, 2 AS admin_level, scalerank,
-           boundary_class(featurecla) AS class
+    SELECT geom, 2 AS admin_level
     FROM ne_10m_admin_0_boundary_lines_land
     UNION ALL
-    SELECT geom, 4 AS admin_level, scalerank,
-           boundary_class(featurecla) AS class
+    SELECT geom, 4 AS admin_level
     FROM ne_10m_admin_1_states_provinces_lines_shp
     WHERE scalerank <= 3 AND featurecla = 'Adm-1 boundary'
 );
 
 CREATE OR REPLACE VIEW boundary_z5 AS (
-    SELECT geom, 2 AS admin_level, scalerank,
-           boundary_class(featurecla) AS class
+    SELECT geom, 2 AS admin_level
     FROM ne_10m_admin_0_boundary_lines_land
     UNION ALL
-    SELECT geom, 4 AS admin_level, scalerank,
-           boundary_class(featurecla) AS class
+    SELECT geom, 4 AS admin_level
     FROM ne_10m_admin_1_states_provinces_lines_shp
     WHERE scalerank <= 7 AND featurecla = 'Adm-1 boundary'
 );
 
 CREATE OR REPLACE VIEW boundary_z7 AS (
-    SELECT geom, 2 AS admin_level, scalerank,
-           boundary_class(featurecla) AS class
+    SELECT geom, 2 AS admin_level
     FROM ne_10m_admin_0_boundary_lines_land
     UNION ALL
-    SELECT geom, 4 AS admin_level, scalerank,
-           boundary_class(featurecla) AS class
+    SELECT geom, 4 AS admin_level
     FROM ne_10m_admin_1_states_provinces_lines_shp
     WHERE featurecla = 'Adm-1 boundary'
 
 );
 
 CREATE OR REPLACE VIEW boundary_z8 AS (
-    SELECT geometry AS geom, admin_level,
-           NULL AS scalerank, NULL AS class
+    SELECT geometry AS geom, admin_level
     FROM osm_boundary_linestring_gen5
     WHERE admin_level <= 4 AND ST_Length(geometry) > 1000
 );
 
 CREATE OR REPLACE VIEW boundary_z9 AS (
-    SELECT geometry AS geom, admin_level,
-           NULL AS scalerank, NULL AS class
+    SELECT geometry AS geom, admin_level
     FROM osm_boundary_linestring_gen4
     WHERE admin_level <= 6
 );
 
 CREATE OR REPLACE VIEW boundary_z10 AS (
-    SELECT geometry AS geom, admin_level,
-           NULL AS scalerank, NULL AS class
+    SELECT geometry AS geom, admin_level
     FROM osm_boundary_linestring_gen3
     WHERE admin_level <= 6
 );
 
 CREATE OR REPLACE VIEW boundary_z11 AS (
-    SELECT geometry AS geom, admin_level,
-           NULL AS scalerank, NULL AS class
+    SELECT geometry AS geom, admin_level
     FROM osm_boundary_linestring_gen2
     WHERE admin_level <= 8
 );
 
 CREATE OR REPLACE VIEW boundary_z12 AS (
-    SELECT geometry AS geom, admin_level,
-           NULL AS scalerank, NULL AS class
+    SELECT geometry AS geom, admin_level
     FROM osm_boundary_linestring_gen1
 );
 
 CREATE OR REPLACE FUNCTION layer_boundary (bbox geometry, zoom_level int)
-RETURNS TABLE(geom geometry, admin_level int, scalerank int, class text) AS $$
-    SELECT geom, admin_level, scalerank::int, class FROM (
+RETURNS TABLE(geometry geometry, admin_level int) AS $$
+    SELECT geom, admin_level FROM (
         SELECT * FROM boundary_z0 WHERE geom && bbox AND zoom_level = 0
         UNION ALL
         SELECT * FROM boundary_z1 WHERE geom && bbox AND zoom_level BETWEEN 1 AND 2
diff --git a/layers/boundary/boundary.yaml b/layers/boundary/boundary.yaml
index 605c2a2e..02cb7237 100644
--- a/layers/boundary/boundary.yaml
+++ b/layers/boundary/boundary.yaml
@@ -1,17 +1,20 @@
 layer:
   id: "boundary"
   description: |
-    Contains [administrative boundaries](http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dadministrative)
-    (no maritime boundaries yet).
-    Until z7 Natural Earth data is used which switches to OSM boundaries after z8.
-  buffer_size: 4
+      Contains administrative boundaries as linestrings (no maritime boundaries yet) as linestrings.
+      Until z7 [Natural Earth data](http://www.naturalearthdata.com/downloads/10m-cultural-vectors/10m-admin-0-countries/)
+      is used after which OSM boundaries ([`boundary=administrative`](http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dadministrative)) are present from z8 to z14.
+      OSM data contains all [`admin_level`](http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dadministrative#admin_level)
+      but for most styles it makes sense to just style `admin_level=2` and `admin_level=4`.
   fields:
     admin_level: |
         OSM [admin_level](http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dadministrative#admin_level)
         indicating the level of importance of this boundary.
         At low zoom levels the Natural Earth boundaries are mapped to the equivalent admin levels.
+  buffer_size: 4
   datasource:
-    query: (SELECT * FROM layer_boundary(!bbox!, z(!scale_denominator!))) AS t
+    geometry_field: geometry
+    query: (SELECT geometry, admin_level FROM layer_boundary(!bbox!, z(!scale_denominator!))) AS t
 schema:
   - ./boundary.sql
 datasources:
diff --git a/layers/boundary/mapping.png b/layers/boundary/mapping.png
new file mode 100644
index 00000000..72032cdf
Binary files /dev/null and b/layers/boundary/mapping.png differ