From 72f5f158282333ad833381154e436e548ee6e2dc Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Mon, 27 Feb 2023 22:05:24 -0500
Subject: [PATCH 01/14] Add LabelCenterline function

---
 sql/LabelCenterline.sql | 69 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 sql/LabelCenterline.sql

diff --git a/sql/LabelCenterline.sql b/sql/LabelCenterline.sql
new file mode 100644
index 00000000..b6625a5f
--- /dev/null
+++ b/sql/LabelCenterline.sql
@@ -0,0 +1,69 @@
+/******************************************************************************
+### LabelCenterline ###
+
+Given a polygon or multipolygon, calculates a linestring suitable for a label.
+
+__Parameters:__
+
+- `geometry` input - A polygon or multipolygon.
+
+__Returns:__ `geometry(linestring)`
+******************************************************************************/
+CREATE OR REPLACE FUNCTION CountDisconnectedEndpoints(polyline geometry, line geometry) RETURNS integer
+    AS 'SELECT ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(polyline)))
+                    - ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(ST_Difference(polyline, line))))
+                    - ST_NPoints(line) + 2;'
+    LANGUAGE SQL
+    IMMUTABLE
+    RETURNS NULL ON NULL INPUT;
+CREATE OR REPLACE FUNCTION TrimmedCenterline(polyline geometry) RETURNS geometry AS '
+    WITH tbla AS (
+        SELECT polyline, (ST_Dump(polyline)).geom as line
+    ),
+    tblb AS (
+        SELECT polyline, line as shortestBranchLine
+        FROM tbla
+        WHERE CountDisconnectedEndpoints(polyline, line) > 0
+        ORDER BY ST_Length(line) ASC
+        LIMIT 1
+    ),
+    tblc AS (
+        SELECT ST_LineMerge(ST_Difference(polyline, shortestBranchLine)) as polyline
+        FROM tblb
+    )
+    SELECT TrimmedCenterline(polyline) as polyline
+    FROM tblc
+    WHERE ST_NumGeometries(polyline) > 1
+    UNION ALL
+    SELECT polyline FROM tblc
+;'
+    LANGUAGE SQL
+    IMMUTABLE
+    RETURNS NULL ON NULL INPUT;
+CREATE OR REPLACE FUNCTION LabelCenterline(input geometry) RETURNS geometry AS '
+    WITH tbla AS (
+        SELECT input as polygon WHERE ST_GeometryType(input) = ''ST_Polygon''
+        UNION ALL
+        SELECT ST_ConcaveHull(input, 0.1) as polygon WHERE ST_GeometryType(input)=''ST_MultiPolygon''
+    ),
+    tblb AS (
+        SELECT ST_MakePolygon(ST_ExteriorRing(polygon)) as polygon
+        FROM tbla
+    ),
+    tblc AS (
+        SELECT polygon, (ST_Dump(ST_VoronoiLines(ST_LineInterpolatePoints(ST_Boundary(polygon), 0.0075)))).geom as lines
+        FROM tblb
+        WHERE ST_GeometryType(polygon) = ''ST_Polygon''
+    ),
+    tbld AS (
+        SELECT ST_LineMerge(ST_Collect(lines)) as polyline
+        FROM tblc
+        WHERE ST_Contains(polygon, lines)
+    )
+    SELECT ST_ChaikinSmoothing(ST_SimplifyPreserveTopology(TrimmedCenterline(polyline), 80), 3, false) FROM tbld
+;'
+    LANGUAGE SQL
+    IMMUTABLE
+    RETURNS NULL ON NULL INPUT;
+
+

From c17a3d750843037ca102dd6d155b0e01a04b778c Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Mon, 27 Feb 2023 22:39:56 -0500
Subject: [PATCH 02/14] Polygon is implied at this step

---
 sql/LabelCenterline.sql | 1 -
 1 file changed, 1 deletion(-)

diff --git a/sql/LabelCenterline.sql b/sql/LabelCenterline.sql
index b6625a5f..1c9eea41 100644
--- a/sql/LabelCenterline.sql
+++ b/sql/LabelCenterline.sql
@@ -53,7 +53,6 @@ CREATE OR REPLACE FUNCTION LabelCenterline(input geometry) RETURNS geometry AS '
     tblc AS (
         SELECT polygon, (ST_Dump(ST_VoronoiLines(ST_LineInterpolatePoints(ST_Boundary(polygon), 0.0075)))).geom as lines
         FROM tblb
-        WHERE ST_GeometryType(polygon) = ''ST_Polygon''
     ),
     tbld AS (
         SELECT ST_LineMerge(ST_Collect(lines)) as polyline

From 3d5b0c8fea3e9ca3d775945d36197062e2876e54 Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Tue, 28 Feb 2023 10:44:16 -0500
Subject: [PATCH 03/14] Convert function from string definitions to plpgsql
 begin/end Speed up multipolygon hull calculations somewhat

---
 sql/LabelCenterline.sql | 118 +++++++++++++++++++++-------------------
 1 file changed, 62 insertions(+), 56 deletions(-)

diff --git a/sql/LabelCenterline.sql b/sql/LabelCenterline.sql
index 1c9eea41..7edb7151 100644
--- a/sql/LabelCenterline.sql
+++ b/sql/LabelCenterline.sql
@@ -5,64 +5,70 @@ Given a polygon or multipolygon, calculates a linestring suitable for a label.
 
 __Parameters:__
 
-- `geometry` input - A polygon or multipolygon.
+- `geometry` inGeometry - A polygon or multipolygon.
 
-__Returns:__ `geometry(linestring)`
+__Returns:__ `geometry(multiline)`
 ******************************************************************************/
-CREATE OR REPLACE FUNCTION CountDisconnectedEndpoints(polyline geometry, line geometry) RETURNS integer
-    AS 'SELECT ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(polyline)))
-                    - ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(ST_Difference(polyline, line))))
-                    - ST_NPoints(line) + 2;'
-    LANGUAGE SQL
-    IMMUTABLE
-    RETURNS NULL ON NULL INPUT;
-CREATE OR REPLACE FUNCTION TrimmedCenterline(polyline geometry) RETURNS geometry AS '
-    WITH tbla AS (
-        SELECT polyline, (ST_Dump(polyline)).geom as line
-    ),
-    tblb AS (
-        SELECT polyline, line as shortestBranchLine
-        FROM tbla
-        WHERE CountDisconnectedEndpoints(polyline, line) > 0
-        ORDER BY ST_Length(line) ASC
-        LIMIT 1
-    ),
-    tblc AS (
-        SELECT ST_LineMerge(ST_Difference(polyline, shortestBranchLine)) as polyline
-        FROM tblb
-    )
-    SELECT TrimmedCenterline(polyline) as polyline
-    FROM tblc
-    WHERE ST_NumGeometries(polyline) > 1
-    UNION ALL
-    SELECT polyline FROM tblc
-;'
-    LANGUAGE SQL
-    IMMUTABLE
-    RETURNS NULL ON NULL INPUT;
-CREATE OR REPLACE FUNCTION LabelCenterline(input geometry) RETURNS geometry AS '
-    WITH tbla AS (
-        SELECT input as polygon WHERE ST_GeometryType(input) = ''ST_Polygon''
-        UNION ALL
-        SELECT ST_ConcaveHull(input, 0.1) as polygon WHERE ST_GeometryType(input)=''ST_MultiPolygon''
-    ),
-    tblb AS (
-        SELECT ST_MakePolygon(ST_ExteriorRing(polygon)) as polygon
-        FROM tbla
-    ),
-    tblc AS (
-        SELECT polygon, (ST_Dump(ST_VoronoiLines(ST_LineInterpolatePoints(ST_Boundary(polygon), 0.0075)))).geom as lines
-        FROM tblb
-    ),
-    tbld AS (
-        SELECT ST_LineMerge(ST_Collect(lines)) as polyline
+CREATE OR REPLACE FUNCTION CountDisconnectedEndpoints(polyline geometry, line geometry)
+    RETURNS integer AS $$
+    BEGIN
+        RETURN ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(polyline)))
+                        - ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(ST_Difference(polyline, line))))
+                        - ST_NPoints(line) + 2;
+    END
+    $$ LANGUAGE plpgsql;
+CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry)
+    RETURNS geometry AS $$
+    DECLARE outPolyline geometry;
+    BEGIN
+        WITH tbla AS (
+            SELECT inPolyline as polyline, (ST_Dump(inPolyline)).geom as line
+        ),
+        tblb AS (
+            SELECT polyline, line as shortestBranchLine
+            FROM tbla
+            WHERE CountDisconnectedEndpoints(polyline, line) > 0
+            ORDER BY ST_Length(line) ASC
+            LIMIT 1
+        ),
+        tblc AS (
+            SELECT ST_LineMerge(ST_Difference(polyline, shortestBranchLine)) as polyline
+            FROM tblb
+        )
+        SELECT TrimmedCenterline(polyline) as polyline
         FROM tblc
-        WHERE ST_Contains(polygon, lines)
-    )
-    SELECT ST_ChaikinSmoothing(ST_SimplifyPreserveTopology(TrimmedCenterline(polyline), 80), 3, false) FROM tbld
-;'
-    LANGUAGE SQL
-    IMMUTABLE
-    RETURNS NULL ON NULL INPUT;
+        WHERE ST_NumGeometries(polyline) > 1
+        UNION ALL
+        SELECT polyline INTO outPolyline FROM tblc;
+        RETURN outPolyline;
+    END
+    $$ LANGUAGE plpgsql;
+CREATE OR REPLACE FUNCTION LabelCenterline(inGeometry geometry)
+    RETURNS geometry AS $$
+    DECLARE outPolyline geometry;
+    BEGIN
+        WITH tbla AS (
+            SELECT inGeometry as polygon WHERE ST_GeometryType(inGeometry) = 'ST_Polygon'
+            UNION ALL
+            SELECT ST_ConcaveHull(ST_Points(ST_Simplify(inGeometry, 25)), 0.2) as polygon WHERE ST_GeometryType(inGeometry)='ST_MultiPolygon'
+        ),
+        tblb AS (
+            SELECT ST_MakePolygon(ST_ExteriorRing(polygon)) as polygon
+            FROM tbla
+        ),
+        tblc AS (
+            SELECT polygon, (ST_Dump(ST_VoronoiLines(ST_LineInterpolatePoints(ST_Boundary(polygon), 0.0075)))).geom as lines
+            FROM tblb
+        ),
+        tbld AS (
+            SELECT ST_LineMerge(ST_Collect(lines)) as polyline
+            FROM tblc
+            WHERE ST_Contains(polygon, lines)
+        )
+        SELECT ST_ChaikinSmoothing(ST_SimplifyPreserveTopology(TrimmedCenterline(polyline), 80), 3, false) INTO outPolyline FROM tbld;
+        RETURN outPolyline;
+    END
+    $$ LANGUAGE plpgsql;
+
 
 

From 966c0a5dd34196659dcd490ac836e7f82e975a78 Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Tue, 28 Feb 2023 10:51:31 -0500
Subject: [PATCH 04/14] Use more descriptive variable names

---
 sql/LabelCenterline.sql | 31 ++++++++++++++-----------------
 1 file changed, 14 insertions(+), 17 deletions(-)

diff --git a/sql/LabelCenterline.sql b/sql/LabelCenterline.sql
index 7edb7151..acac30ea 100644
--- a/sql/LabelCenterline.sql
+++ b/sql/LabelCenterline.sql
@@ -9,12 +9,12 @@ __Parameters:__
 
 __Returns:__ `geometry(multiline)`
 ******************************************************************************/
-CREATE OR REPLACE FUNCTION CountDisconnectedEndpoints(polyline geometry, line geometry)
+CREATE OR REPLACE FUNCTION CountDisconnectedEndpoints(polyline geometry, testline geometry)
     RETURNS integer AS $$
     BEGIN
         RETURN ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(polyline)))
-                        - ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(ST_Difference(polyline, line))))
-                        - ST_NPoints(line) + 2;
+                    - ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(ST_Difference(polyline, testline))))
+                    - ST_NPoints(testline) + 2;
     END
     $$ LANGUAGE plpgsql;
 CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry)
@@ -22,13 +22,13 @@ CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry)
     DECLARE outPolyline geometry;
     BEGIN
         WITH tbla AS (
-            SELECT inPolyline as polyline, (ST_Dump(inPolyline)).geom as line
+            SELECT inPolyline as polyline, (ST_Dump(inPolyline)).geom as edge
         ),
         tblb AS (
-            SELECT polyline, line as shortestBranchLine
+            SELECT polyline, edge as shortestBranchLine
             FROM tbla
-            WHERE CountDisconnectedEndpoints(polyline, line) > 0
-            ORDER BY ST_Length(line) ASC
+            WHERE CountDisconnectedEndpoints(polyline, edge) > 0
+            ORDER BY ST_Length(edge) ASC
             LIMIT 1
         ),
         tblc AS (
@@ -48,27 +48,24 @@ CREATE OR REPLACE FUNCTION LabelCenterline(inGeometry geometry)
     DECLARE outPolyline geometry;
     BEGIN
         WITH tbla AS (
-            SELECT inGeometry as polygon WHERE ST_GeometryType(inGeometry) = 'ST_Polygon'
+            SELECT inGeometry as inPolygon WHERE ST_GeometryType(inGeometry) = 'ST_Polygon'
             UNION ALL
-            SELECT ST_ConcaveHull(ST_Points(ST_Simplify(inGeometry, 25)), 0.2) as polygon WHERE ST_GeometryType(inGeometry)='ST_MultiPolygon'
+            SELECT ST_ConcaveHull(ST_Points(ST_Simplify(inGeometry, 25)), 0.2) as inPolygon WHERE ST_GeometryType(inGeometry)='ST_MultiPolygon'
         ),
         tblb AS (
-            SELECT ST_MakePolygon(ST_ExteriorRing(polygon)) as polygon
+            SELECT ST_MakePolygon(ST_ExteriorRing(inPolygon)) as shellPolygon
             FROM tbla
         ),
         tblc AS (
-            SELECT polygon, (ST_Dump(ST_VoronoiLines(ST_LineInterpolatePoints(ST_Boundary(polygon), 0.0075)))).geom as lines
+            SELECT shellPolygon, (ST_Dump(ST_VoronoiLines(ST_LineInterpolatePoints(ST_Boundary(shellPolygon), 0.0075)))).geom as voroniLines
             FROM tblb
         ),
         tbld AS (
-            SELECT ST_LineMerge(ST_Collect(lines)) as polyline
+            SELECT ST_LineMerge(ST_Collect(voroniLines)) as voroniPolyline
             FROM tblc
-            WHERE ST_Contains(polygon, lines)
+            WHERE ST_Contains(shellPolygon, voroniLines)
         )
-        SELECT ST_ChaikinSmoothing(ST_SimplifyPreserveTopology(TrimmedCenterline(polyline), 80), 3, false) INTO outPolyline FROM tbld;
+        SELECT ST_ChaikinSmoothing(ST_SimplifyPreserveTopology(TrimmedCenterline(voroniPolyline), 80), 3, false) INTO outPolyline FROM tbld;
         RETURN outPolyline;
     END
     $$ LANGUAGE plpgsql;
-
-
-

From 3d77ebc2ec9c19deff4a934605b99f1271f4b1f5 Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Tue, 28 Feb 2023 16:22:37 -0500
Subject: [PATCH 05/14] Multipoint-based hull causes some issues

---
 sql/LabelCenterline.sql | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sql/LabelCenterline.sql b/sql/LabelCenterline.sql
index acac30ea..86b07de0 100644
--- a/sql/LabelCenterline.sql
+++ b/sql/LabelCenterline.sql
@@ -50,7 +50,7 @@ CREATE OR REPLACE FUNCTION LabelCenterline(inGeometry geometry)
         WITH tbla AS (
             SELECT inGeometry as inPolygon WHERE ST_GeometryType(inGeometry) = 'ST_Polygon'
             UNION ALL
-            SELECT ST_ConcaveHull(ST_Points(ST_Simplify(inGeometry, 25)), 0.2) as inPolygon WHERE ST_GeometryType(inGeometry)='ST_MultiPolygon'
+            SELECT ST_ConcaveHull(ST_Simplify(inGeometry, 25), 0.2) as inPolygon WHERE ST_GeometryType(inGeometry)='ST_MultiPolygon'
         ),
         tblb AS (
             SELECT ST_MakePolygon(ST_ExteriorRing(inPolygon)) as shellPolygon

From 5fe3a050b3ac59b6841b98407b0c830e774613e5 Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Sun, 5 Mar 2023 13:19:02 -0500
Subject: [PATCH 06/14] 2x faster execution by avoiding ST_Difference entirely

---
 sql/LabelCenterline.sql | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/sql/LabelCenterline.sql b/sql/LabelCenterline.sql
index 86b07de0..adea8f7e 100644
--- a/sql/LabelCenterline.sql
+++ b/sql/LabelCenterline.sql
@@ -11,10 +11,17 @@ __Returns:__ `geometry(multiline)`
 ******************************************************************************/
 CREATE OR REPLACE FUNCTION CountDisconnectedEndpoints(polyline geometry, testline geometry)
     RETURNS integer AS $$
+    DECLARE count integer;
     BEGIN
-        RETURN ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(polyline)))
-                    - ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(ST_Difference(polyline, testline))))
-                    - ST_NPoints(testline) + 2;
+        WITH linesExceptTestline AS (
+            SELECT (ST_Dump(polyline)).geom as linestring
+            EXCEPT
+            SELECT testline as linestring
+        )
+        SELECT ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(polyline)))
+                    - ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(ST_Collect(linestring))))
+                    - ST_NPoints(testline) + 2 INTO count FROM linesExceptTestline;
+        RETURN count;
     END
     $$ LANGUAGE plpgsql;
 CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry)
@@ -22,24 +29,29 @@ CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry)
     DECLARE outPolyline geometry;
     BEGIN
         WITH tbla AS (
-            SELECT inPolyline as polyline, (ST_Dump(inPolyline)).geom as edge
+            SELECT (ST_Dump(inPolyline)).geom as edge
         ),
         tblb AS (
-            SELECT polyline, edge as shortestBranchLine
+            SELECT edge
             FROM tbla
-            WHERE CountDisconnectedEndpoints(polyline, edge) > 0
+            WHERE CountDisconnectedEndpoints(inPolyline, edge) > 0
             ORDER BY ST_Length(edge) ASC
             LIMIT 1
         ),
         tblc AS (
-            SELECT ST_LineMerge(ST_Difference(polyline, shortestBranchLine)) as polyline
-            FROM tblb
+            SELECT * FROM tbla
+            EXCEPT
+            SELECT * FROM tblb
+        ),
+        tbld AS (
+            SELECT ST_LineMerge(ST_Collect(edge)) as polyline
+            FROM tblc
         )
         SELECT TrimmedCenterline(polyline) as polyline
-        FROM tblc
+        FROM tbld
         WHERE ST_NumGeometries(polyline) > 1
         UNION ALL
-        SELECT polyline INTO outPolyline FROM tblc;
+        SELECT polyline INTO outPolyline FROM tbld;
         RETURN outPolyline;
     END
     $$ LANGUAGE plpgsql;

From 8eba5d57a3de6835eaf6060e495063c9f35d0d9d Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Sun, 5 Mar 2023 14:15:43 -0500
Subject: [PATCH 07/14] Create separate centerline for each part of a
 multipolygon instead of using a concave hull

---
 sql/LabelCenterline.sql | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/sql/LabelCenterline.sql b/sql/LabelCenterline.sql
index adea8f7e..fd0b4826 100644
--- a/sql/LabelCenterline.sql
+++ b/sql/LabelCenterline.sql
@@ -59,25 +59,28 @@ CREATE OR REPLACE FUNCTION LabelCenterline(inGeometry geometry)
     RETURNS geometry AS $$
     DECLARE outPolyline geometry;
     BEGIN
-        WITH tbla AS (
+        WITH polygons AS (
             SELECT inGeometry as inPolygon WHERE ST_GeometryType(inGeometry) = 'ST_Polygon'
             UNION ALL
-            SELECT ST_ConcaveHull(ST_Simplify(inGeometry, 25), 0.2) as inPolygon WHERE ST_GeometryType(inGeometry)='ST_MultiPolygon'
+            SELECT (ST_Dump(inGeometry)).geom as inPolygon WHERE ST_GeometryType(inGeometry)='ST_MultiPolygon'
         ),
-        tblb AS (
+        shellPolygons AS (
             SELECT ST_MakePolygon(ST_ExteriorRing(inPolygon)) as shellPolygon
-            FROM tbla
+            FROM polygons
         ),
-        tblc AS (
+        allVoroniLines AS (
             SELECT shellPolygon, (ST_Dump(ST_VoronoiLines(ST_LineInterpolatePoints(ST_Boundary(shellPolygon), 0.0075)))).geom as voroniLines
-            FROM tblb
+            FROM shellPolygons
         ),
-        tbld AS (
+        containedVoroniPolylines AS (
             SELECT ST_LineMerge(ST_Collect(voroniLines)) as voroniPolyline
-            FROM tblc
+            FROM allVoroniLines
             WHERE ST_Contains(shellPolygon, voroniLines)
+            GROUP BY shellPolygon
         )
-        SELECT ST_ChaikinSmoothing(ST_SimplifyPreserveTopology(TrimmedCenterline(voroniPolyline), 80), 3, false) INTO outPolyline FROM tbld;
+        SELECT ST_ChaikinSmoothing(ST_SimplifyPreserveTopology(ST_Collect(TrimmedCenterline(voroniPolyline)), 80), 3, false) as trimmedPolyline
+        INTO outPolyline
+        FROM containedVoroniPolylines;
         RETURN outPolyline;
     END
     $$ LANGUAGE plpgsql;

From 9bf39d7fd3be5e4ff0b25a806b8612fe26daf039 Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Sun, 5 Mar 2023 14:18:03 -0500
Subject: [PATCH 08/14] Uppercase `as`

---
 sql/LabelCenterline.sql | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/sql/LabelCenterline.sql b/sql/LabelCenterline.sql
index fd0b4826..79622b70 100644
--- a/sql/LabelCenterline.sql
+++ b/sql/LabelCenterline.sql
@@ -14,9 +14,9 @@ CREATE OR REPLACE FUNCTION CountDisconnectedEndpoints(polyline geometry, testlin
     DECLARE count integer;
     BEGIN
         WITH linesExceptTestline AS (
-            SELECT (ST_Dump(polyline)).geom as linestring
+            SELECT (ST_Dump(polyline)).geom AS linestring
             EXCEPT
-            SELECT testline as linestring
+            SELECT testline AS linestring
         )
         SELECT ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(polyline)))
                     - ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(ST_Collect(linestring))))
@@ -29,7 +29,7 @@ CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry)
     DECLARE outPolyline geometry;
     BEGIN
         WITH tbla AS (
-            SELECT (ST_Dump(inPolyline)).geom as edge
+            SELECT (ST_Dump(inPolyline)).geom AS edge
         ),
         tblb AS (
             SELECT edge
@@ -44,10 +44,10 @@ CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry)
             SELECT * FROM tblb
         ),
         tbld AS (
-            SELECT ST_LineMerge(ST_Collect(edge)) as polyline
+            SELECT ST_LineMerge(ST_Collect(edge)) AS polyline
             FROM tblc
         )
-        SELECT TrimmedCenterline(polyline) as polyline
+        SELECT TrimmedCenterline(polyline) AS polyline
         FROM tbld
         WHERE ST_NumGeometries(polyline) > 1
         UNION ALL
@@ -60,25 +60,25 @@ CREATE OR REPLACE FUNCTION LabelCenterline(inGeometry geometry)
     DECLARE outPolyline geometry;
     BEGIN
         WITH polygons AS (
-            SELECT inGeometry as inPolygon WHERE ST_GeometryType(inGeometry) = 'ST_Polygon'
+            SELECT inGeometry AS inPolygon WHERE ST_GeometryType(inGeometry) = 'ST_Polygon'
             UNION ALL
-            SELECT (ST_Dump(inGeometry)).geom as inPolygon WHERE ST_GeometryType(inGeometry)='ST_MultiPolygon'
+            SELECT (ST_Dump(inGeometry)).geom AS inPolygon WHERE ST_GeometryType(inGeometry)='ST_MultiPolygon'
         ),
         shellPolygons AS (
-            SELECT ST_MakePolygon(ST_ExteriorRing(inPolygon)) as shellPolygon
+            SELECT ST_MakePolygon(ST_ExteriorRing(inPolygon)) AS shellPolygon
             FROM polygons
         ),
         allVoroniLines AS (
-            SELECT shellPolygon, (ST_Dump(ST_VoronoiLines(ST_LineInterpolatePoints(ST_Boundary(shellPolygon), 0.0075)))).geom as voroniLines
+            SELECT shellPolygon, (ST_Dump(ST_VoronoiLines(ST_LineInterpolatePoints(ST_Boundary(shellPolygon), 0.0075)))).geom AS voroniLines
             FROM shellPolygons
         ),
         containedVoroniPolylines AS (
-            SELECT ST_LineMerge(ST_Collect(voroniLines)) as voroniPolyline
+            SELECT ST_LineMerge(ST_Collect(voroniLines)) AS voroniPolyline
             FROM allVoroniLines
             WHERE ST_Contains(shellPolygon, voroniLines)
             GROUP BY shellPolygon
         )
-        SELECT ST_ChaikinSmoothing(ST_SimplifyPreserveTopology(ST_Collect(TrimmedCenterline(voroniPolyline)), 80), 3, false) as trimmedPolyline
+        SELECT ST_ChaikinSmoothing(ST_SimplifyPreserveTopology(ST_Collect(TrimmedCenterline(voroniPolyline)), 80), 3, false) AS trimmedPolyline
         INTO outPolyline
         FROM containedVoroniPolylines;
         RETURN outPolyline;

From 4d3474c8b27cd4976afc08a73174cc2f0520c9a6 Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Sun, 5 Mar 2023 14:30:16 -0500
Subject: [PATCH 09/14] Avoid unnecessary plpgsql. Make functions immutable,
 strict, parallel safe

---
 sql/LabelCenterline.sql | 35 ++++++++++++++---------------------
 1 file changed, 14 insertions(+), 21 deletions(-)

diff --git a/sql/LabelCenterline.sql b/sql/LabelCenterline.sql
index 79622b70..69a2b70e 100644
--- a/sql/LabelCenterline.sql
+++ b/sql/LabelCenterline.sql
@@ -10,9 +10,9 @@ __Parameters:__
 __Returns:__ `geometry(multiline)`
 ******************************************************************************/
 CREATE OR REPLACE FUNCTION CountDisconnectedEndpoints(polyline geometry, testline geometry)
-    RETURNS integer AS $$
-    DECLARE count integer;
-    BEGIN
+    RETURNS integer
+    LANGUAGE sql IMMUTABLE STRICT PARALLEL SAFE
+    BEGIN ATOMIC
         WITH linesExceptTestline AS (
             SELECT (ST_Dump(polyline)).geom AS linestring
             EXCEPT
@@ -20,14 +20,12 @@ CREATE OR REPLACE FUNCTION CountDisconnectedEndpoints(polyline geometry, testlin
         )
         SELECT ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(polyline)))
                     - ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(ST_Collect(linestring))))
-                    - ST_NPoints(testline) + 2 INTO count FROM linesExceptTestline;
-        RETURN count;
-    END
-    $$ LANGUAGE plpgsql;
+                    - ST_NPoints(testline) + 2 FROM linesExceptTestline;
+    END;
 CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry)
-    RETURNS geometry AS $$
-    DECLARE outPolyline geometry;
-    BEGIN
+    RETURNS geometry
+    LANGUAGE sql IMMUTABLE STRICT PARALLEL SAFE
+    BEGIN ATOMIC
         WITH tbla AS (
             SELECT (ST_Dump(inPolyline)).geom AS edge
         ),
@@ -51,14 +49,12 @@ CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry)
         FROM tbld
         WHERE ST_NumGeometries(polyline) > 1
         UNION ALL
-        SELECT polyline INTO outPolyline FROM tbld;
-        RETURN outPolyline;
-    END
-    $$ LANGUAGE plpgsql;
+        SELECT polyline FROM tbld;
+    END;
 CREATE OR REPLACE FUNCTION LabelCenterline(inGeometry geometry)
-    RETURNS geometry AS $$
-    DECLARE outPolyline geometry;
-    BEGIN
+    RETURNS geometry
+    LANGUAGE sql IMMUTABLE STRICT PARALLEL SAFE
+    BEGIN ATOMIC
         WITH polygons AS (
             SELECT inGeometry AS inPolygon WHERE ST_GeometryType(inGeometry) = 'ST_Polygon'
             UNION ALL
@@ -79,8 +75,5 @@ CREATE OR REPLACE FUNCTION LabelCenterline(inGeometry geometry)
             GROUP BY shellPolygon
         )
         SELECT ST_ChaikinSmoothing(ST_SimplifyPreserveTopology(ST_Collect(TrimmedCenterline(voroniPolyline)), 80), 3, false) AS trimmedPolyline
-        INTO outPolyline
         FROM containedVoroniPolylines;
-        RETURN outPolyline;
-    END
-    $$ LANGUAGE plpgsql;
+    END;

From ada765382830c93baa2be8e27635df5397d7a687 Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Sun, 5 Mar 2023 14:34:57 -0500
Subject: [PATCH 10/14] Name remaining CTE tables

---
 sql/LabelCenterline.sql | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/sql/LabelCenterline.sql b/sql/LabelCenterline.sql
index 69a2b70e..dc9ebb39 100644
--- a/sql/LabelCenterline.sql
+++ b/sql/LabelCenterline.sql
@@ -26,30 +26,30 @@ CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry)
     RETURNS geometry
     LANGUAGE sql IMMUTABLE STRICT PARALLEL SAFE
     BEGIN ATOMIC
-        WITH tbla AS (
+        WITH edges AS (
             SELECT (ST_Dump(inPolyline)).geom AS edge
         ),
-        tblb AS (
-            SELECT edge
-            FROM tbla
+        shortestBranchEdge AS (
+            SELECT *
+            FROM edges
             WHERE CountDisconnectedEndpoints(inPolyline, edge) > 0
             ORDER BY ST_Length(edge) ASC
             LIMIT 1
         ),
-        tblc AS (
-            SELECT * FROM tbla
+        edgesWithoutShortestBranch AS (
+            SELECT * FROM edges
             EXCEPT
-            SELECT * FROM tblb
+            SELECT * FROM shortestBranchEdge
         ),
-        tbld AS (
+        trimmedPolyline AS (
             SELECT ST_LineMerge(ST_Collect(edge)) AS polyline
-            FROM tblc
+            FROM edgesWithoutShortestBranch
         )
         SELECT TrimmedCenterline(polyline) AS polyline
-        FROM tbld
+        FROM trimmedPolyline
         WHERE ST_NumGeometries(polyline) > 1
         UNION ALL
-        SELECT polyline FROM tbld;
+        SELECT polyline FROM trimmedPolyline;
     END;
 CREATE OR REPLACE FUNCTION LabelCenterline(inGeometry geometry)
     RETURNS geometry

From 5c47d32e907d3f654ce90bc029dc7d2b26c41ce8 Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Sun, 5 Mar 2023 16:00:32 -0500
Subject: [PATCH 11/14] Add parameters to control centerline creation

---
 sql/LabelCenterline.sql | 41 +++++++++++++++++++++++++++++++++++------
 1 file changed, 35 insertions(+), 6 deletions(-)

diff --git a/sql/LabelCenterline.sql b/sql/LabelCenterline.sql
index dc9ebb39..44df0b00 100644
--- a/sql/LabelCenterline.sql
+++ b/sql/LabelCenterline.sql
@@ -6,6 +6,10 @@ Given a polygon or multipolygon, calculates a linestring suitable for a label.
 __Parameters:__
 
 - `geometry` inGeometry - A polygon or multipolygon.
+- `integer` maxVoronoiVertices - The maximum number of points per polygon of the `geometry` that will be used to calculate the centerline. Lower values will significantly increase execution speed but can result in much less accurate results. Set to `0` to use all points of the input geometry (maximum accuracy). 
+- `float` sourceSimplification - The `tolerance` parameter of `ST_SimplifyPreserveTopology`, applied to the polygon before the centerline is calculated. Higher values will increase execution speed but can result in less accurate results. Set to `0` to disable simplification (maximum accuracy).
+- `float` simplification - The `tolerance` parameter of `ST_SimplifyPreserveTopology`, applied to the output centerline. Does not appreciably affect performance. Set to `0` to disable simplification.
+- `integer` smoothingReps - The number of smoothing iterations to apply to the output centerline. Corresponds to the `nIterations` parameter of `ST_ChaikinSmoothing`. Does not appreciably affect performance. Set to `0` to disable smoothing.
 
 __Returns:__ `geometry(multiline)`
 ******************************************************************************/
@@ -51,7 +55,14 @@ CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry)
         UNION ALL
         SELECT polyline FROM trimmedPolyline;
     END;
-CREATE OR REPLACE FUNCTION LabelCenterline(inGeometry geometry)
+DROP FUNCTION LabelCenterline(geometry, integer, float, float, integer);
+CREATE OR REPLACE FUNCTION LabelCenterline(
+    inGeometry geometry,
+    maxVoronoiVertices integer default 100,
+    sourceSimplification float default 0,
+    simplification float default 100,
+    smoothingReps integer default 3
+)
     RETURNS geometry
     LANGUAGE sql IMMUTABLE STRICT PARALLEL SAFE
     BEGIN ATOMIC
@@ -61,19 +72,37 @@ CREATE OR REPLACE FUNCTION LabelCenterline(inGeometry geometry)
             SELECT (ST_Dump(inGeometry)).geom AS inPolygon WHERE ST_GeometryType(inGeometry)='ST_MultiPolygon'
         ),
         shellPolygons AS (
-            SELECT ST_MakePolygon(ST_ExteriorRing(inPolygon)) AS shellPolygon
+            SELECT ST_SimplifyPreserveTopology(ST_MakePolygon(ST_ExteriorRing(inPolygon)), sourceSimplification) AS shellPolygon
             FROM polygons
         ),
-        allVoroniLines AS (
-            SELECT shellPolygon, (ST_Dump(ST_VoronoiLines(ST_LineInterpolatePoints(ST_Boundary(shellPolygon), 0.0075)))).geom AS voroniLines
+        shellVertices AS (
+            SELECT shellPolygon, ST_LineInterpolatePoints(ST_Boundary(shellPolygon), 1.0/maxVoronoiVertices) as vertices
+            FROM shellPolygons
+            WHERE maxVoronoiVertices > 0 AND ST_NPoints(shellPolygon) > maxVoronoiVertices
+            UNION ALL
+            SELECT shellPolygon, ST_Points(shellPolygon) as vertices
             FROM shellPolygons
+            WHERE maxVoronoiVertices = 0 OR ST_NPoints(shellPolygon) <= maxVoronoiVertices
+        ),
+        allVoroniLines AS (
+            SELECT shellPolygon, (ST_Dump(ST_VoronoiLines(vertices))).geom AS voroniLines
+            FROM shellVertices
         ),
         containedVoroniPolylines AS (
             SELECT ST_LineMerge(ST_Collect(voroniLines)) AS voroniPolyline
             FROM allVoroniLines
             WHERE ST_Contains(shellPolygon, voroniLines)
             GROUP BY shellPolygon
+        ),
+        simplifedCenterline AS (
+            SELECT ST_SimplifyPreserveTopology(ST_Collect(TrimmedCenterline(voroniPolyline)), simplification) AS polyline
+            FROM containedVoroniPolylines
         )
-        SELECT ST_ChaikinSmoothing(ST_SimplifyPreserveTopology(ST_Collect(TrimmedCenterline(voroniPolyline)), 80), 3, false) AS trimmedPolyline
-        FROM containedVoroniPolylines;
+        SELECT ST_ChaikinSmoothing(polyline, smoothingReps, false) AS polyline
+        FROM simplifedCenterline
+        WHERE smoothingReps != 0
+        UNION ALL
+        SELECT *
+        FROM simplifedCenterline
+        WHERE smoothingReps = 0;
     END;

From a83ebde55de03cf522b87d97548d5375e393868b Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Sun, 5 Mar 2023 16:31:34 -0500
Subject: [PATCH 12/14] Don't need drop

---
 sql/LabelCenterline.sql | 1 -
 1 file changed, 1 deletion(-)

diff --git a/sql/LabelCenterline.sql b/sql/LabelCenterline.sql
index 44df0b00..00d08326 100644
--- a/sql/LabelCenterline.sql
+++ b/sql/LabelCenterline.sql
@@ -55,7 +55,6 @@ CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry)
         UNION ALL
         SELECT polyline FROM trimmedPolyline;
     END;
-DROP FUNCTION LabelCenterline(geometry, integer, float, float, integer);
 CREATE OR REPLACE FUNCTION LabelCenterline(
     inGeometry geometry,
     maxVoronoiVertices integer default 100,

From d1586bd28c410942a60162babf0b1d505c8317ea Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Sun, 5 Mar 2023 20:23:38 -0500
Subject: [PATCH 13/14] Add parameter to enable multiple branches in the output
 (useful for polygons with lots bulges/arms)

---
 sql/LabelCenterline.sql | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/sql/LabelCenterline.sql b/sql/LabelCenterline.sql
index 00d08326..d5bcd529 100644
--- a/sql/LabelCenterline.sql
+++ b/sql/LabelCenterline.sql
@@ -1,13 +1,14 @@
 /******************************************************************************
 ### LabelCenterline ###
 
-Given a polygon or multipolygon, calculates a linestring suitable for a label.
+Given a polygon or multipolygon, calculates one or more linestrings suitable for labeling.
 
 __Parameters:__
 
 - `geometry` inGeometry - A polygon or multipolygon.
 - `integer` maxVoronoiVertices - The maximum number of points per polygon of the `geometry` that will be used to calculate the centerline. Lower values will significantly increase execution speed but can result in much less accurate results. Set to `0` to use all points of the input geometry (maximum accuracy). 
 - `float` sourceSimplification - The `tolerance` parameter of `ST_SimplifyPreserveTopology`, applied to the polygon before the centerline is calculated. Higher values will increase execution speed but can result in less accurate results. Set to `0` to disable simplification (maximum accuracy).
+- `float` minSegmentLengthRatio - The minimum length allowed for a branch or independent segment relative to the total length of the output. Set to `1` to return only a single centerline. Set to `0` to include all branches (not recommended). Values between `0.15 and 0.25` tend to have nice results for polygons with multiple "arms".
 - `float` simplification - The `tolerance` parameter of `ST_SimplifyPreserveTopology`, applied to the output centerline. Does not appreciably affect performance. Set to `0` to disable simplification.
 - `integer` smoothingReps - The number of smoothing iterations to apply to the output centerline. Corresponds to the `nIterations` parameter of `ST_ChaikinSmoothing`. Does not appreciably affect performance. Set to `0` to disable smoothing.
 
@@ -26,18 +27,26 @@ CREATE OR REPLACE FUNCTION CountDisconnectedEndpoints(polyline geometry, testlin
                     - ST_NPoints(ST_RemoveRepeatedPoints(ST_Points(ST_Collect(linestring))))
                     - ST_NPoints(testline) + 2 FROM linesExceptTestline;
     END;
-CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry)
+CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry, minSegmentLengthRatio float)
     RETURNS geometry
     LANGUAGE sql IMMUTABLE STRICT PARALLEL SAFE
     BEGIN ATOMIC
         WITH edges AS (
             SELECT (ST_Dump(inPolyline)).geom AS edge
         ),
-        shortestBranchEdge AS (
-            SELECT *
+        edgesWithLength AS (
+            SELECT edge, ST_Length(edge) AS edgeLength
             FROM edges
+        ),
+        edgesSummary AS (
+           SELECT sum(edgeLength) AS totalEdgeLength FROM edgesWithLength
+        ),
+        shortestBranchEdge AS (
+            SELECT edge
+            FROM edgesWithLength
             WHERE CountDisconnectedEndpoints(inPolyline, edge) > 0
-            ORDER BY ST_Length(edge) ASC
+                AND edgeLength < (SELECT totalEdgeLength FROM edgesSummary) * minSegmentLengthRatio
+            ORDER BY edgeLength ASC
             LIMIT 1
         ),
         edgesWithoutShortestBranch AS (
@@ -49,9 +58,11 @@ CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry)
             SELECT ST_LineMerge(ST_Collect(edge)) AS polyline
             FROM edgesWithoutShortestBranch
         )
-        SELECT TrimmedCenterline(polyline) AS polyline
+        SELECT TrimmedCenterline(polyline, minSegmentLengthRatio) AS polyline
         FROM trimmedPolyline
         WHERE ST_NumGeometries(polyline) > 1
+            -- if we didn't trim anything then we're done
+            AND ST_NumGeometries(polyline) != ST_NumGeometries(inPolyline)
         UNION ALL
         SELECT polyline FROM trimmedPolyline;
     END;
@@ -59,6 +70,7 @@ CREATE OR REPLACE FUNCTION LabelCenterline(
     inGeometry geometry,
     maxVoronoiVertices integer default 100,
     sourceSimplification float default 0,
+    minSegmentLengthRatio float default 1, --0.175 is a good value if you want to allow a couple big branches
     simplification float default 100,
     smoothingReps integer default 3
 )
@@ -75,11 +87,11 @@ CREATE OR REPLACE FUNCTION LabelCenterline(
             FROM polygons
         ),
         shellVertices AS (
-            SELECT shellPolygon, ST_LineInterpolatePoints(ST_Boundary(shellPolygon), 1.0/maxVoronoiVertices) as vertices
+            SELECT shellPolygon, ST_LineInterpolatePoints(ST_Boundary(shellPolygon), 1.0/maxVoronoiVertices) AS vertices
             FROM shellPolygons
             WHERE maxVoronoiVertices > 0 AND ST_NPoints(shellPolygon) > maxVoronoiVertices
             UNION ALL
-            SELECT shellPolygon, ST_Points(shellPolygon) as vertices
+            SELECT shellPolygon, ST_Points(shellPolygon) AS vertices
             FROM shellPolygons
             WHERE maxVoronoiVertices = 0 OR ST_NPoints(shellPolygon) <= maxVoronoiVertices
         ),
@@ -94,10 +106,10 @@ CREATE OR REPLACE FUNCTION LabelCenterline(
             GROUP BY shellPolygon
         ),
         simplifedCenterline AS (
-            SELECT ST_SimplifyPreserveTopology(ST_Collect(TrimmedCenterline(voroniPolyline)), simplification) AS polyline
+            SELECT ST_SimplifyPreserveTopology(ST_Union(TrimmedCenterline(voroniPolyline, minSegmentLengthRatio)), simplification) AS polyline
             FROM containedVoroniPolylines
         )
-        SELECT ST_ChaikinSmoothing(polyline, smoothingReps, false) AS polyline
+        SELECT ST_ChaikinSmoothing(polyline, smoothingReps, true /* preserveEndPoints */) AS polyline
         FROM simplifedCenterline
         WHERE smoothingReps != 0
         UNION ALL

From 9f75d705812a9b613878ef18ee82e96f71c99395 Mon Sep 17 00:00:00 2001
From: Quincy Morgan <2046746+quincylvania@users.noreply.github.com>
Date: Fri, 10 Mar 2023 13:42:36 -0500
Subject: [PATCH 14/14] Support holes Make simplification parameters ratios to
 scale to geometries of vastly different scales

---
 sql/LabelCenterline.sql | 96 ++++++++++++++++++++++++++++++-----------
 1 file changed, 72 insertions(+), 24 deletions(-)

diff --git a/sql/LabelCenterline.sql b/sql/LabelCenterline.sql
index d5bcd529..58abaab7 100644
--- a/sql/LabelCenterline.sql
+++ b/sql/LabelCenterline.sql
@@ -7,9 +7,10 @@ __Parameters:__
 
 - `geometry` inGeometry - A polygon or multipolygon.
 - `integer` maxVoronoiVertices - The maximum number of points per polygon of the `geometry` that will be used to calculate the centerline. Lower values will significantly increase execution speed but can result in much less accurate results. Set to `0` to use all points of the input geometry (maximum accuracy). 
-- `float` sourceSimplification - The `tolerance` parameter of `ST_SimplifyPreserveTopology`, applied to the polygon before the centerline is calculated. Higher values will increase execution speed but can result in less accurate results. Set to `0` to disable simplification (maximum accuracy).
+- `float` sourceSimplificationRatio - The `tolerance` parameter of `ST_SimplifyPreserveTopology` as a fraction of the geometry's bounding box, applied to the polygon before the centerline is calculated. Higher values will increase execution speed but can result in less accurate results. Set to `0` to disable simplification (maximum accuracy).
 - `float` minSegmentLengthRatio - The minimum length allowed for a branch or independent segment relative to the total length of the output. Set to `1` to return only a single centerline. Set to `0` to include all branches (not recommended). Values between `0.15 and 0.25` tend to have nice results for polygons with multiple "arms".
-- `float` simplification - The `tolerance` parameter of `ST_SimplifyPreserveTopology`, applied to the output centerline. Does not appreciably affect performance. Set to `0` to disable simplification.
+- `float` minHoleAreaRatio - The minimum area of a hole relative to the total area of the geometry for it to be included. Set to `1` to ignore all holes. Set to `0` to account for all holes.
+- `float` simplificationRatio - The `tolerance` parameter of `ST_SimplifyPreserveTopology` as a fraction of the geometry's bounding box, applied to the output centerline. Does not appreciably affect performance. Set to `0` to disable simplification.
 - `integer` smoothingReps - The number of smoothing iterations to apply to the output centerline. Corresponds to the `nIterations` parameter of `ST_ChaikinSmoothing`. Does not appreciably affect performance. Set to `0` to disable smoothing.
 
 __Returns:__ `geometry(multiline)`
@@ -69,45 +70,92 @@ CREATE OR REPLACE FUNCTION TrimmedCenterline(inPolyline geometry, minSegmentLeng
 CREATE OR REPLACE FUNCTION LabelCenterline(
     inGeometry geometry,
     maxVoronoiVertices integer default 100,
-    sourceSimplification float default 0,
-    minSegmentLengthRatio float default 1, --0.175 is a good value if you want to allow a couple big branches
-    simplification float default 100,
+    sourceSimplificationRatio float default 0.0001,
+    minSegmentLengthRatio float default 1, -- 0.175 is a good value if you want to allow a couple big branches
+    minHoleAreaRatio float default 1, -- 0.01 has decent results for ignoring all but the largest holes
+    simplificationRatio float default 0.02,
     smoothingReps integer default 3
 )
     RETURNS geometry
     LANGUAGE sql IMMUTABLE STRICT PARALLEL SAFE
     BEGIN ATOMIC
-        WITH polygons AS (
-            SELECT inGeometry AS inPolygon WHERE ST_GeometryType(inGeometry) = 'ST_Polygon'
+        WITH inGeometryInfo AS (
+            SELECT LEAST(ST_XMax(inGeometry)-ST_XMin(inGeometry), ST_YMax(inGeometry)-ST_YMin(inGeometry)) AS leastBBoxDimension
+        ), simplifiedGeometry AS (
+            SELECT ST_MakeValid(ST_Simplify(inGeometry, (SELECT leastBBoxDimension * sourceSimplificationRatio FROM inGeometryInfo), false)) AS inGeometry
+        ), polygons AS (
+            SELECT inGeometry AS inPolygon
+            FROM simplifiedGeometry
+            WHERE ST_GeometryType(inGeometry) = 'ST_Polygon'
             UNION ALL
-            SELECT (ST_Dump(inGeometry)).geom AS inPolygon WHERE ST_GeometryType(inGeometry)='ST_MultiPolygon'
+            SELECT (ST_Dump(inGeometry)).geom AS inPolygon
+            FROM simplifiedGeometry
+            WHERE ST_GeometryType(inGeometry)='ST_MultiPolygon'
         ),
-        shellPolygons AS (
-            SELECT ST_SimplifyPreserveTopology(ST_MakePolygon(ST_ExteriorRing(inPolygon)), sourceSimplification) AS shellPolygon
+        polygonsSummary AS (
+            SELECT inPolygon, ST_Area(Box2D(inPolygon)) AS exteriorRingArea, ST_DumpRings(inPolygon) AS ringInfo
             FROM polygons
         ),
-        shellVertices AS (
-            SELECT shellPolygon, ST_LineInterpolatePoints(ST_Boundary(shellPolygon), 1.0/maxVoronoiVertices) AS vertices
-            FROM shellPolygons
-            WHERE maxVoronoiVertices > 0 AND ST_NPoints(shellPolygon) > maxVoronoiVertices
+        rings AS (
+            SELECT inPolygon, exteriorRingArea, ST_ExteriorRing((ringInfo).geom) AS ring, (ringInfo).path[1] AS ringNum
+            FROM polygonsSummary
+        ),
+        largeEnoughRings AS ( 
+            SELECT inPolygon, ring
+            FROM rings
+            --always keep the exterior ring
+            WHERE ringNum = 0
+                OR ST_Area(Box2D(ST_LineInterpolatePoints(ring, 0.05))) >= exteriorRingArea * minHoleAreaRatio
+        ),
+        filteredRings AS ( 
+            SELECT *
+            FROM largeEnoughRings
+            WHERE minHoleAreaRatio < 1
+            UNION ALL
+            SELECT inPolygon, ST_ExteriorRing(inPolygon) AS ring
+            FROM polygons
+            WHERE minHoleAreaRatio >= 1
+        ),
+        preppedRings AS (
+            SELECT inPolygon, ring, ST_LineInterpolatePoints(ring, 1.0/maxVoronoiVertices) AS voronoiVertices
+            FROM filteredRings
+            WHERE maxVoronoiVertices > 0 AND ST_NPoints(ring) > maxVoronoiVertices
             UNION ALL
-            SELECT shellPolygon, ST_Points(shellPolygon) AS vertices
-            FROM shellPolygons
-            WHERE maxVoronoiVertices = 0 OR ST_NPoints(shellPolygon) <= maxVoronoiVertices
+            SELECT inPolygon, ring, ST_Points(ring) AS voronoiVertices
+            FROM filteredRings
+            WHERE maxVoronoiVertices = 0 OR ST_NPoints(ring) <= maxVoronoiVertices
+        ),
+        ringArrays AS (
+            SELECT (array_agg(ring)) AS ringArray, ST_Collect(voronoiVertices) AS voronoiVertices
+            FROM preppedRings
+            GROUP BY inPolygon
+        ),
+        preppedPolygons AS (
+            SELECT ST_MakePolygon(ringArray[1], ringArray[2:]) AS preppedPolygon, voronoiVertices
+            FROM ringArrays
         ),
         allVoroniLines AS (
-            SELECT shellPolygon, (ST_Dump(ST_VoronoiLines(vertices))).geom AS voroniLines
-            FROM shellVertices
+            SELECT preppedPolygon, (ST_Dump(ST_VoronoiLines(voronoiVertices))).geom AS voroniLine
+            FROM preppedPolygons
         ),
         containedVoroniPolylines AS (
-            SELECT ST_LineMerge(ST_Collect(voroniLines)) AS voroniPolyline
+            SELECT ST_LineMerge(ST_Collect(voroniLine)) AS voroniPolyline
             FROM allVoroniLines
-            WHERE ST_Contains(shellPolygon, voroniLines)
-            GROUP BY shellPolygon
+            WHERE ST_Contains(preppedPolygon, voroniLine)
+            GROUP BY preppedPolygon
         ),
-        simplifedCenterline AS (
-            SELECT ST_SimplifyPreserveTopology(ST_Union(TrimmedCenterline(voroniPolyline, minSegmentLengthRatio)), simplification) AS polyline
+        centerline AS (
+            SELECT ST_Union(TrimmedCenterline(voroniPolyline, minSegmentLengthRatio)) AS polyline
             FROM containedVoroniPolylines
+        ),
+        simplifedCenterline AS (
+            SELECT ST_SimplifyPreserveTopology(polyline, (SELECT leastBBoxDimension*simplificationRatio FROM inGeometryInfo)) AS polyline
+            FROM centerline
+            WHERE simplificationRatio != 0
+            UNION ALL
+            SELECT *
+            FROM centerline
+            WHERE simplificationRatio = 0
         )
         SELECT ST_ChaikinSmoothing(polyline, smoothingReps, true /* preserveEndPoints */) AS polyline
         FROM simplifedCenterline