diff --git a/src/main/java/org/gcube/portlets/user/geoportaldataviewer/client/gis/LayerOrder.java b/src/main/java/org/gcube/portlets/user/geoportaldataviewer/client/gis/LayerOrder.java
new file mode 100644
index 0000000..940f016
--- /dev/null
+++ b/src/main/java/org/gcube/portlets/user/geoportaldataviewer/client/gis/LayerOrder.java
@@ -0,0 +1,51 @@
+package org.gcube.portlets.user.geoportaldataviewer.client.gis;
+
+import java.util.HashMap;
+
+/**
+ * The Class LayerOrder.
+ *
+ * @author Francesco Mangiacrapa at ISTI-CNR francesco.mangiacrapa@isti.cnr.it
+ * 
+ *         Nov 12, 2021
+ */
+public class LayerOrder {
+
+	/**
+	 * The Enum LAYER_TYPE.
+	 *
+	 * @author Francesco Mangiacrapa at ISTI-CNR francesco.mangiacrapa@isti.cnr.it
+	 * 
+	 *         Nov 12, 2021
+	 */
+	public static enum LAYER_TYPE {
+		BASE_MAP, BASE_WMS, WMS_DETAIL, VECTOR
+	}
+
+	public static final HashMap<LAYER_TYPE, Integer> LAYER_OFFSET = new HashMap<LAYER_TYPE, Integer>(5);
+
+	static {
+
+		LAYER_OFFSET.put(LAYER_TYPE.BASE_MAP, 0);
+		LAYER_OFFSET.put(LAYER_TYPE.BASE_WMS, 70);
+		LAYER_OFFSET.put(LAYER_TYPE.WMS_DETAIL, 140);
+		LAYER_OFFSET.put(LAYER_TYPE.VECTOR, 210);
+	}
+
+	/**
+	 * Instantiates a new layer order.
+	 */
+	public LayerOrder() {
+	}
+
+	/**
+	 * Gets the offset.
+	 *
+	 * @param layerType the layer type
+	 * @return the offset
+	 */
+	public Integer getOffset(LAYER_TYPE layerType) {
+		return LAYER_OFFSET.get(layerType);
+	}
+
+}
diff --git a/src/main/java/org/gcube/portlets/user/geoportaldataviewer/client/gis/OpenLayerOSM.java b/src/main/java/org/gcube/portlets/user/geoportaldataviewer/client/gis/OpenLayerOSM.java
index cbe9b44..fdc6711 100644
--- a/src/main/java/org/gcube/portlets/user/geoportaldataviewer/client/gis/OpenLayerOSM.java
+++ b/src/main/java/org/gcube/portlets/user/geoportaldataviewer/client/gis/OpenLayerOSM.java
@@ -141,7 +141,9 @@ public abstract class OpenLayerOSM {
 	private LinkedHashMap<String, Image> wmsLayerMap;
 
 	private Layer baseLayerTile;
-
+	
+	private LayerOrder layerOrder = new LayerOrder();
+	
 
 	/**
 	 * Instantiates a new open layer OSM.
@@ -219,7 +221,8 @@ public abstract class OpenLayerOSM {
 			//osmSource.setAttributions(baseLayer.getAttribution());
 			LayerOptions layerOptions = OLFactory.createOptions();
 			layerOptions.setSource(osmSource);
-			layerOptions.setZIndex(0);
+			int zIndex = layerOrder.getOffset(LayerOrder.LAYER_TYPE.BASE_MAP)+1;
+			layerOptions.setZIndex(zIndex);
 			baseLayerTile = new Tile(layerOptions);
 
 			break;
@@ -234,11 +237,13 @@ public abstract class OpenLayerOSM {
 
 			LayerOptions layerOptions2 = OLFactory.createOptions();
 			layerOptions2.setSource(xyz);
-			layerOptions2.setZIndex(0);
+			zIndex = layerOrder.getOffset(LayerOrder.LAYER_TYPE.BASE_MAP)+1;
+			layerOptions2.setZIndex(zIndex);
 			baseLayerTile = new Tile(layerOptions2);
 	
 
 			break;
+
 		}
 
 		// map == null at init time
@@ -405,6 +410,8 @@ public abstract class OpenLayerOSM {
 
 			LayerOptions layerOptions = OLFactory.createOptions();
 			layerOptions.setSource(imageWMSSource);
+			
+			
 
 			// Settings MIN and MAX Resolution
 			if (layerItem.getMinResolution() != null) {
@@ -415,7 +422,8 @@ public abstract class OpenLayerOSM {
 			}
 
 			Image wmsLayer = new Image(layerOptions);
-
+			int zIndex = layerOrder.getOffset(LayerOrder.LAYER_TYPE.BASE_WMS)+wmsLayerMap.size()+1;
+			wmsLayer.setZIndex(zIndex);
 			// visibleLayerItems
 
 			map.addLayer(wmsLayer);
@@ -457,6 +465,9 @@ public abstract class OpenLayerOSM {
 
 			LayerOptions layerOptions = OLFactory.createOptions();
 			layerOptions.setSource(imageWMSSource);
+			
+
+			
 			// Settings MIN and MAX Resolution
 			if (layerItem.getMinResolution() != null) {
 				layerOptions.setMinResolution(layerItem.getMinResolution());
@@ -466,7 +477,8 @@ public abstract class OpenLayerOSM {
 			}
 
 			Image wmsLayer = new Image(layerOptions);
-			wmsLayer.setZIndex(wmsDetailsLayerMap.size() + 1);
+			int zIndex = layerOrder.getOffset(LayerOrder.LAYER_TYPE.WMS_DETAIL)+wmsDetailsLayerMap.size() + 1;
+			wmsLayer.setZIndex(zIndex);
 			map.addLayer(wmsLayer);
 			wmsDetailsLayerMap.put(key, wmsLayer);
 
@@ -523,9 +535,12 @@ public abstract class OpenLayerOSM {
 		Vector vectorSource = OLFactory.createVectorSource();
 		vectorSource.addFeature(feature);
 		vectorLayerOptions.setSource(vectorSource);
-
+		
 		ol.layer.Vector vector = OLFactory.createVector(vectorLayerOptions);
-
+		
+		int zIndex = layerOrder.getOffset(LayerOrder.LAYER_TYPE.VECTOR)+1;
+		vector.setZIndex(zIndex);
+		
 		map.addLayer(vector);
 	}
 
@@ -875,9 +890,11 @@ public abstract class OpenLayerOSM {
 		Image layer1 = wmsDetailsLayerMap.get(layerSource);
 		Image layer2 = wmsDetailsLayerMap.get(layerTarget);
 
-		int zIndexS = swapLSource.getPosition() + 1;
-		int zIndexT = swapLTarget.getPosition() + 1;
+		int zIndexOffset = layerOrder.getOffset(LayerOrder.LAYER_TYPE.WMS_DETAIL);
+		int zIndexS = swapLSource.getPosition() + zIndexOffset + 1;
+		int zIndexT = swapLTarget.getPosition() + zIndexOffset + 1;
 		GWT.log("new zindex source: " + zIndexS + ", new zTarget: " + zIndexT);
+
 		layer1.setZIndex(zIndexT);
 		layer2.setZIndex(zIndexS);