diff --git a/src/main/java/org/gcube/contentmanagement/graphtools/utils/MathFunctions.java b/src/main/java/org/gcube/contentmanagement/graphtools/utils/MathFunctions.java
index cefa02d..a68d322 100644
--- a/src/main/java/org/gcube/contentmanagement/graphtools/utils/MathFunctions.java
+++ b/src/main/java/org/gcube/contentmanagement/graphtools/utils/MathFunctions.java
@@ -300,11 +300,11 @@ public class MathFunctions {
 			return "Poor";
 		else if ((kappa>=0)&&(kappa<=0.20))
 			return "Slight";
-		else if ((kappa>=0.21)&&(kappa<=0.40))
+		else if ((kappa>=0.20)&&(kappa<=0.40))
 			return "Fair";
-		else if ((kappa>=0.41)&&(kappa<=0.60))
+		else if ((kappa>0.40)&&(kappa<=0.60))
 			return "Moderate";
-		else if ((kappa>=0.61)&&(kappa<=0.80))
+		else if ((kappa>0.60)&&(kappa<=0.80))
 			return "Substantial";
 		else if (kappa>=0.81)
 			return "Almost Perfect";
diff --git a/src/main/java/org/gcube/dataanalysis/ecoengine/clustering/DBScan.java b/src/main/java/org/gcube/dataanalysis/ecoengine/clustering/DBScan.java
index fde6616..8426a3c 100644
--- a/src/main/java/org/gcube/dataanalysis/ecoengine/clustering/DBScan.java
+++ b/src/main/java/org/gcube/dataanalysis/ecoengine/clustering/DBScan.java
@@ -203,7 +203,11 @@ public class DBScan implements Clusterer{
 		DatabaseFactory.executeSQLUpdate(DatabaseUtils.addColumnStatement(OccurrencePointsClusterTable, outliersColumn, outliersColumnType), dbHibConnection);
 		AnalysisLogger.getLogger().debug("Getting Samples");
 		//build samples
+		try{
 		getSamples();
+		}catch(Throwable e){
+			AnalysisLogger.getLogger().debug("Error getting samples for clustering: "+e.getLocalizedMessage());
+		}
 		status = 10f;
 	}