diff --git a/klab.engine/pom.xml b/klab.engine/pom.xml
index a5b6fbf53..275bd8293 100644
--- a/klab.engine/pom.xml
+++ b/klab.engine/pom.xml
@@ -329,9 +329,19 @@
                     <groupId>org.mongodb</groupId>
                     <artifactId>mongo-java-driver</artifactId>
                 </exclusion>
+                <exclusion>
+                    <groupId>org.locationtech.jts</groupId>
+                    <artifactId>jts-core</artifactId>
+                </exclusion>
             </exclusions>
         </dependency>
 
+        <dependency>
+            <groupId>org.locationtech.jts</groupId>
+            <artifactId>jts-core</artifactId>
+            <version>${jts.version}</version>		
+        </dependency>
+
 		<!-- all of a sudden, WCS parsing stops working unless this is added. -->
 		<dependency>
 			<groupId>xml-apis</groupId>
@@ -642,6 +652,12 @@
 			<groupId>org.orbisgis</groupId>
 			<artifactId>h2gis</artifactId>
 			<version>2.1.0</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>org.locationtech.jts</groupId>
+                    <artifactId>jts-core</artifactId>
+                </exclusion>
+            </exclusions>
 		</dependency>
 
 		<!-- https://mvnrepository.com/artifact/args4j/args4j startup options parser -->
@@ -718,11 +734,23 @@
 			<groupId>org.geotools</groupId>
 			<artifactId>gt-process</artifactId>
 			<version>${geotools.version}</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>org.locationtech.jts</groupId>
+                    <artifactId>jts-core</artifactId>
+                </exclusion>
+            </exclusions>
 		</dependency>
 		<dependency>
 			<groupId>org.geotools</groupId>
 			<artifactId>gt-process-raster</artifactId>
 			<version>${geotools.version}</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>org.locationtech.jts</groupId>
+                    <artifactId>jts-core</artifactId>
+                </exclusion>
+            </exclusions>
 		</dependency>
 		<dependency>
 			<groupId>org.geotools</groupId>
diff --git a/klab.engine/src/main/java/org/integratedmodelling/klab/components/geospace/processing/Rasterizer.java b/klab.engine/src/main/java/org/integratedmodelling/klab/components/geospace/processing/Rasterizer.java
index 6b09195a5..8f294978e 100644
--- a/klab.engine/src/main/java/org/integratedmodelling/klab/components/geospace/processing/Rasterizer.java
+++ b/klab.engine/src/main/java/org/integratedmodelling/klab/components/geospace/processing/Rasterizer.java
@@ -29,6 +29,7 @@
 import org.locationtech.jts.geom.MultiPolygon;
 import org.locationtech.jts.geom.Point;
 import org.locationtech.jts.geom.Polygon;
+import org.locationtech.jts.triangulate.polygon.PolygonTriangulator;
 
 /**
  * Simple, flexible rasterizer using an AWT image as a backend and closures to determine (a) the
@@ -131,9 +132,8 @@ public Collection<Coordinate> getCoordinates(IShape shape) {
 
         Geometry geometry = ((Shape) shape).getJTSGeometry();
         Color valueColor = new Color(255, 255, 255);
-        Color holeColor = new Color(0, 0, 0);
 
-        draw(geometry, valueColor, holeColor);
+        draw(geometry, valueColor);
 
         int[] xy = new int[2];
         for (int x = 0; x < this.raster.getWidth(); x++) {
@@ -165,14 +165,12 @@ public void add(IShape shape, Function<IShape, T> encoder) {
         Geometry geometry = ((Shape) shape).getJTSGeometry();
 
         int rgbVal = floatBitsToInt(encodeToFloat(value));
-        int holeVal = floatBitsToInt(Float.NaN);
         Color valueColor = new Color(rgbVal, true);
-        Color holeColor = new Color(holeVal, true);
 
-        draw(geometry, valueColor, holeColor);
+        draw(geometry, valueColor);
     }
 
-    private void draw(Geometry geometry, Color valueColor, Color holeColor) {
+    private void draw(Geometry geometry, Color valueColor) {
 
         Geometries geomType = Geometries.get(geometry);
         if (geomType == Geometries.MULTIPOLYGON || geomType == Geometries.MULTILINESTRING
@@ -180,7 +178,7 @@ private void draw(Geometry geometry, Color valueColor, Color holeColor) {
             final int numGeom = geometry.getNumGeometries();
             for (int i = 0; i < numGeom; i++) {
                 Geometry geomN = geometry.getGeometryN(i);
-                draw(geomN, valueColor, holeColor);
+                draw(geomN, valueColor);
             }
         } else /* if (geometry.intersects(((Grid) extent).getShape().getJTSGeometry())) */ {
 
@@ -188,13 +186,12 @@ private void draw(Geometry geometry, Color valueColor, Color holeColor) {
 
                 for (int i = 0; i < geometry.getNumGeometries(); i++) {
                     Polygon poly = (Polygon) geometry.getGeometryN(i);
-                    LinearRing lr = geoFactory.createLinearRing(poly.getExteriorRing().getCoordinates());
-                    Polygon part = geoFactory.createPolygon(lr, null);
-                    drawGeometry(part, valueColor);
-                    for (int j = 0; j < poly.getNumInteriorRing(); j++) {
-                        lr = geoFactory.createLinearRing(poly.getInteriorRingN(j).getCoordinates());
-                        part = geoFactory.createPolygon(lr, null);
-                        drawGeometry(part, holeColor);
+                    boolean hasHoles = poly.getNumInteriorRing() > 0;
+                    if (hasHoles) {
+                        Geometry triangles = PolygonTriangulator.triangulate(poly);
+                        draw(triangles, valueColor);
+                    } else {
+                        drawGeometry(poly, valueColor);
                     }
                 }
             } else {
diff --git a/pom.xml b/pom.xml
index a1c1b0706..b91616930 100644
--- a/pom.xml
+++ b/pom.xml
@@ -100,7 +100,7 @@
 			should be the same one that geotools and HM needs. -->
 		<geotools.version>28.0</geotools.version>
 		<hortonmachine.version>0.10.9-SNAPSHOT</hortonmachine.version>
-		<jts.version>1.18.1</jts.version>
+		<jts.version>1.20.0</jts.version>
 		<h2gis.version>1.5.0</h2gis.version>
 		<maven.compiler.source>11</maven.compiler.source>
 		<maven.compiler.target>11</maven.compiler.target>