Index: /issm/trunk-jpl/src/m/geometry/slope.m
===================================================================
--- /issm/trunk-jpl/src/m/geometry/slope.m	(revision 14799)
+++ /issm/trunk-jpl/src/m/geometry/slope.m	(revision 14800)
@@ -1,7 +1,8 @@
-function [sx,sy,s]=slope(md)
+function [sx,sy,s]=slope(md,surf)
 %SLOPE - compute the surface slope
 %
 %   Usage:
 %      [sx,sy,s]=slope(md)
+%      [sx,sy,s]=slope(md,md.results.TransientSolution(1).Surface)
 
 %load some variables (it is much faster if the variab;es are loaded from md once for all) 
@@ -18,10 +19,13 @@
 end
 
+if nargin==1,
+	surf=md.geometry.surface;
+end
 %compute nodal functions coefficients N(x,y)=alpha x + beta y + gamma
 [alpha beta]=GetNodalFunctionsCoeff(index,x,y);
 
 summation=[1;1;1];
-sx=(md.geometry.surface(index).*alpha)*summation;
-sy=(md.geometry.surface(index).*beta)*summation;
+sx=(surf(index).*alpha)*summation;
+sy=(surf(index).*beta)*summation;
 s=sqrt(sx.^2+sy.^2);