Index: /trunk/Ohana/src/libdvo/include/dvo.h
===================================================================
--- /trunk/Ohana/src/libdvo/include/dvo.h	(revision 10930)
+++ /trunk/Ohana/src/libdvo/include/dvo.h	(revision 10931)
@@ -370,4 +370,5 @@
 SkyList   *SkyListByBounds     	   PROTO((SkyTable *table, int depth, double Rmin, double Rmax, double Dmin, double Dmax));
 SkyList   *SkyListChildrenByBounds PROTO((SkyTable *table, int No, int depth, double Rmin, double Rmax, double Dmin, double Dmax));
+int        SkyListMerge     	   PROTO((SkyList **outlist, SkyList *newlist));
 int        SkyListFree             PROTO((SkyList *list, int ELEMENTS));
 int        SkyTableFree            PROTO((SkyTable *table));
Index: /trunk/Ohana/src/libdvo/src/skyregion_ops.c
===================================================================
--- /trunk/Ohana/src/libdvo/src/skyregion_ops.c	(revision 10930)
+++ /trunk/Ohana/src/libdvo/src/skyregion_ops.c	(revision 10931)
@@ -364,4 +364,42 @@
   table = NULL;
   return (TRUE);
+}
+
+int SkyListMerge (SkyList **outlist, SkyList *newlist) {
+
+    int i, j, skip, Nlist, Ntotal;
+    SkyList *list;
+    
+    if (*outlist == NULL) {
+	ALLOCATE (list, SkyList, 1);
+	ALLOCATE (list[0].regions, SkyRegion *, 1);
+	ALLOCATE (list[0].filename, char *, 1);
+	list[0].Nregions = 0;
+	*outlist = list;
+    } else {
+	list = *outlist;
+    }
+
+    Ntotal = list[0].Nregions + newlist[0].Nregions;
+    REALLOCATE (list[0].regions, SkyRegion *, Ntotal);
+    REALLOCATE (list[0].filename, char *, Ntotal);
+
+    Nlist = list[0].Nregions;
+    for (i = 0; i < newlist[0].Nregions; i++) {
+	/* check existing list to see if we already have this region */
+	skip = FALSE;
+	for (j = 0; j < list[0].Nregions; j++) {
+	    if (list[0].regions[j] == newlist[0].regions[i]) skip = TRUE;
+	}
+	if (skip) continue;
+	list[0].regions[Nlist] = newlist[0].regions[i];
+	list[0].filename[Nlist] = newlist[0].filename[i];
+	Nlist++;
+    }
+    list[0].Nregions = Nlist;
+    REALLOCATE (list[0].regions, SkyRegion *, Nlist);
+    REALLOCATE (list[0].filename, char *, Nlist);
+
+    return (TRUE);
 }