Index: /issm/trunk-jpl/src/m/classes/geometry.m
===================================================================
--- /issm/trunk-jpl/src/m/classes/geometry.m	(revision 23844)
+++ /issm/trunk-jpl/src/m/classes/geometry.m	(revision 23845)
@@ -66,5 +66,5 @@
 				if strcmp(solution,'TransientSolution') & md.transient.isgroundingline,
 					md = checkfield(md,'fieldname','geometry.bed','NaN',1,'Inf',1,'size',[md.mesh.numberofvertices 1]);
-					if any(self.bed>self.base),
+					if any(self.bed-self.base>10^-12),
 						md = checkmessage(md,['base<bed on one or more vertex']);
 					end 
Index: /issm/trunk-jpl/src/m/classes/geometry.py
===================================================================
--- /issm/trunk-jpl/src/m/classes/geometry.py	(revision 23844)
+++ /issm/trunk-jpl/src/m/classes/geometry.py	(revision 23845)
@@ -58,5 +58,5 @@
 			if solution=='TransientSolution' and md.transient.isgroundingline:
 				md = checkfield(md,'fieldname','geometry.bed','NaN',1,'Inf',1,'size',[md.mesh.numberofvertices])
-				if np.any(self.bed > self.base):
+				if np.any(self.bed - self.base > 10**-12):
 				    md.checkmessage('base<bed on one or more vertex')
 				pos = np.where(md.mask.groundedice_levelset > 0)