diff --git a/data-discovery/src/main/java/webapi/formatfilter/Dataset.java b/data-discovery/src/main/java/webapi/formatfilter/Dataset.java
index da87a712b02e6dbf6ad96ebfe00e2f2fd3fb124c..717ddecdd3eccd735161bdc94861c1dcfbacb5c9 100644
--- a/data-discovery/src/main/java/webapi/formatfilter/Dataset.java
+++ b/data-discovery/src/main/java/webapi/formatfilter/Dataset.java
@@ -26,9 +26,9 @@ class Dataset
    }
 
 
-   int overlapCodeSky;
-   int overlapCodeVel;
-   int overlapCode;
+   Integer overlapCodeSky;
+   Integer overlapCodeVel;
+   Integer overlapCode;
    String dataType;
    String publisherDid;
    Access access;
diff --git a/data-discovery/src/main/java/webapi/formatfilter/FormatResponseFilter.java b/data-discovery/src/main/java/webapi/formatfilter/FormatResponseFilter.java
index 126b5e64f0e77c5c0fe06e5d47ed867e17427fc4..20ca749c3f8c4afb7f53ca3b64159cef81aa0ae6 100644
--- a/data-discovery/src/main/java/webapi/formatfilter/FormatResponseFilter.java
+++ b/data-discovery/src/main/java/webapi/formatfilter/FormatResponseFilter.java
@@ -264,7 +264,7 @@ public class FormatResponseFilter implements Filter
    }
 
 
-   private int convertToOverlapCodeSky(boolean inpInDb, boolean dbInInp)
+   private Integer convertToOverlapCodeSky(boolean inpInDb, boolean dbInInp)
    {
       if(!inpInDb && !dbInInp) return 4; // parial overlap
       else if( inpInDb && !dbInInp) return 3; // input region completely inside fits-datacube
@@ -273,7 +273,7 @@ public class FormatResponseFilter implements Filter
    }
 
 
-   private int convertToOverlapCodeVel(Band band, boolean v_valid, double v_min, double v_max)
+   private Integer convertToOverlapCodeVel(Band band, boolean v_valid, double v_min, double v_max)
    {
       if((band != null) && v_valid)
       {
@@ -291,19 +291,19 @@ public class FormatResponseFilter implements Filter
             return convertToOverlapCodeSky(inpInDb, dbInInp);
 
          }
-         else ;// FIXME other v_type NotImplemented yet
+         else return null;// FIXME other v_type NotImplemented yet
       }
 
-      return -1; // FIXME use enums; meaning: overlap code in velocity not applicable --> dont print in XML
+      return null;
    }
 
 
 
-   private int convertToOverlapCode(int ovcSky, int ovcVel)
+   private Integer convertToOverlapCode(Integer ovcSky, Integer ovcVel)
    {
-      if(ovcVel == -1) return ovcSky; // 2D images
+      if(ovcVel == null) return ovcSky; // 2D images
       else if(ovcSky == ovcVel) return ovcSky;
-      else return 4;
+      else return 4;// partial overlap
    }