Index: /issm/trunk-jpl/src/m/classes/mesh2d.py
===================================================================
--- /issm/trunk-jpl/src/m/classes/mesh2d.py	(revision 21574)
+++ /issm/trunk-jpl/src/m/classes/mesh2d.py	(revision 21575)
@@ -92,4 +92,5 @@
 		md = checkfield(md,'fieldname','mesh.numberofvertices','>',0)
 		md = checkfield(md,'fieldname','mesh.average_vertex_connectivity','>=',9,'message',"'mesh.average_vertex_connectivity' should be at least 9 in 2d")
+		md = checkfield(md,'fieldname','mesh.segments','NaN',1,'Inf',1,'>',0,'size',[np.nan,3]);
 		if solution=='ThermalSolution':
 			md.checkmessage("thermal not supported for 2d mesh")
@@ -117,3 +118,4 @@
 		WriteData(fid,prefix,'object',self,'class','mesh','fieldname','numberofvertices','format','Integer')
 		WriteData(fid,prefix,'object',self,'class','mesh','fieldname','average_vertex_connectivity','format','Integer')
+		WriteData(fid,prefix,'object',self,'class','mesh','fieldname','segments','format','DoubleMat','mattype',3);
 	# }}}