Index: ../trunk-jpl/src/m/classes/flowequation.py
===================================================================
--- ../trunk-jpl/src/m/classes/flowequation.py	(revision 20281)
+++ ../trunk-jpl/src/m/classes/flowequation.py	(revision 20282)
@@ -137,26 +137,28 @@
 		WriteData(fid,'object',self,'fieldname','borderHO','format','DoubleMat','mattype',1)
 		WriteData(fid,'object',self,'fieldname','borderFS','format','DoubleMat','mattype',1)
 		#convert approximations to enums
-		data=copy.deepcopy(self.vertex_equation)
-		data[numpy.nonzero(data==0)]=NoneApproximationEnum()
-		data[numpy.nonzero(data==1)]=SIAApproximationEnum()
-		data[numpy.nonzero(data==2)]=SSAApproximationEnum()
-		data[numpy.nonzero(data==3)]=L1L2ApproximationEnum()
-		data[numpy.nonzero(data==4)]=HOApproximationEnum()
-		data[numpy.nonzero(data==5)]=FSApproximationEnum()
-		data[numpy.nonzero(data==6)]=SSAHOApproximationEnum()
-		data[numpy.nonzero(data==7)]=HOFSApproximationEnum()
-		data[numpy.nonzero(data==8)]=SSAFSApproximationEnum()
+		data=copy.deepcopy(self.vertex_equation); 
+		if numpy.isnan(data)==0:
+			data[numpy.nonzero(data==0)]=NoneApproximationEnum()
+			data[numpy.nonzero(data==1)]=SIAApproximationEnum()
+			data[numpy.nonzero(data==2)]=SSAApproximationEnum()
+			data[numpy.nonzero(data==3)]=L1L2ApproximationEnum()
+			data[numpy.nonzero(data==4)]=HOApproximationEnum()
+			data[numpy.nonzero(data==5)]=FSApproximationEnum()
+			data[numpy.nonzero(data==6)]=SSAHOApproximationEnum()
+			data[numpy.nonzero(data==7)]=HOFSApproximationEnum()
+			data[numpy.nonzero(data==8)]=SSAFSApproximationEnum()
 		WriteData(fid,'data',data,'enum',FlowequationVertexEquationEnum(),'format','DoubleMat','mattype',1)
 		data=copy.deepcopy(self.element_equation)
-		data[numpy.nonzero(data==0)]=NoneApproximationEnum()
-		data[numpy.nonzero(data==1)]=SIAApproximationEnum()
-		data[numpy.nonzero(data==2)]=SSAApproximationEnum()
-		data[numpy.nonzero(data==3)]=L1L2ApproximationEnum()
-		data[numpy.nonzero(data==4)]=HOApproximationEnum()
-		data[numpy.nonzero(data==5)]=FSApproximationEnum()
-		data[numpy.nonzero(data==6)]=SSAHOApproximationEnum()
-		data[numpy.nonzero(data==7)]=SSAFSApproximationEnum()
-		data[numpy.nonzero(data==8)]=HOFSApproximationEnum()
+		if numpy.isnan(data)==0:
+			data[numpy.nonzero(data==0)]=NoneApproximationEnum()
+			data[numpy.nonzero(data==1)]=SIAApproximationEnum()
+			data[numpy.nonzero(data==2)]=SSAApproximationEnum()
+			data[numpy.nonzero(data==3)]=L1L2ApproximationEnum()
+			data[numpy.nonzero(data==4)]=HOApproximationEnum()
+			data[numpy.nonzero(data==5)]=FSApproximationEnum()
+			data[numpy.nonzero(data==6)]=SSAHOApproximationEnum()
+			data[numpy.nonzero(data==7)]=SSAFSApproximationEnum()
+			data[numpy.nonzero(data==8)]=HOFSApproximationEnum()
 		WriteData(fid,'data',data,'enum',FlowequationElementEquationEnum(),'format','DoubleMat','mattype',2)
 	# }}}