add LandCover layer to Overture example

Overture.java

@@ -6,6 +6,7 @@
 import com.onthegomap.planetiler.util.Glob;
 
 import overturelayers.Building;
+import overturelayers.LandCover;
 import overturelayers.Transportation;
 import overturelayers.Water;
 
@@ -25,6 +26,7 @@ public class Overture extends ForwardingProfile {
   Overture(PlanetilerConfig config) {
     super(config);
     registerHandler(new Water(config));
+    registerHandler(new LandCover(config));
     registerHandler(new Transportation(config));
     registerHandler(new Building());
   }

overturelayers/LandCover.java

@@ -0,0 +1,40 @@
+package overturelayers;
+
+import java.util.List;
+
+import com.onthegomap.planetiler.FeatureCollector;
+import com.onthegomap.planetiler.FeatureMerge;
+import com.onthegomap.planetiler.ForwardingProfile.LayerPostProcesser;
+import com.onthegomap.planetiler.VectorTile.Feature;
+import com.onthegomap.planetiler.geo.GeometryException;
+import com.onthegomap.planetiler.config.PlanetilerConfig;
+import com.onthegomap.planetiler.reader.SourceFeature;
+
+public class LandCover extends BaseLayer implements LayerPostProcesser {
+
+  private PlanetilerConfig config;
+
+  public LandCover(PlanetilerConfig config) {
+    super("land_cover", List.of("land_cover"));
+    this.config = config;
+  }
+
+  @Override
+  public void processFeature(SourceFeature sourceFeature, FeatureCollector features) {
+    var cartography = sourceFeature.getStruct("cartography");
+    var minZoom = cartography.get("min_zoom").asInt();
+    var maxZoom = cartography.get("max_zoom").asInt();
+
+    features.polygon("land_cover")
+        .setMinZoom(minZoom)
+        .setMaxZoom(maxZoom)
+        .inheritAttrsFromSource("subtype");
+  }
+
+  @Override
+  public List<Feature> postProcess(int zoom, List<Feature> items) throws GeometryException {
+    double minSize = zoom < 13 ? 8 : config.minFeatureSize(zoom);
+    items = FeatureMerge.mergeOverlappingPolygons(items, minSize);
+    return items;
+  }
+}