Index: /issm/trunk-jpl/src/m/exp/contourlevelzero.m
===================================================================
--- /issm/trunk-jpl/src/m/exp/contourlevelzero.m	(revision 16517)
+++ /issm/trunk-jpl/src/m/exp/contourlevelzero.m	(revision 16517)
@@ -0,0 +1,199 @@
+function contours=contourlevelzero(md,mask,level)
+%CONTOURLEVELZERO - figure out the zero level (or offset thereof, specified by the level value) 
+%                   of a vectorial mask, and vectorialize it into an exp or shp compatible 
+%structure.
+%
+%   Usage:
+%      contours=contourlevelzero(md,mask,level)
+%
+%   See also: PLOT_CONTOUR
+
+%process data 
+if md.mesh.dimension==3,
+	error('contourlevelzero error message: routine not supported for 3d meshes, project on a layer');
+end
+
+x=md.mesh.x;
+y=md.mesh.y;
+index=md.mesh.elements;
+
+if isempty(mask), error('mask provided is empty'); end
+	if length(mask)~=md.mesh.numberofvertices, error('mask provided should be specified at the vertices of the mesh'); end
+
+%initialization of some variables
+numberofelements=size(index,1);
+elementslist=1:numberofelements;
+c=[];
+h=[];
+
+%get unique edges in mesh
+%1: list of edges
+edges=[index(:,[1,2]); index(:,[2,3]); index(:,[3,1])];
+%2: find unique edges
+[edges,I,J]=unique(sort(edges,2),'rows');
+%3: unique edge numbers
+vec=J;
+%4: unique edges numbers in each triangle (2 triangles sharing the same edge will have
+%   the same edge number)
+edges_tria=[vec(elementslist), vec(elementslist+numberofelements), vec(elementslist+2*numberofelements)];
+
+%segments [nodes1 nodes2]
+Seg1=index(:,[1 2]);
+Seg2=index(:,[2 3]);
+Seg3=index(:,[3 1]);
+
+%segment numbers [1;4;6;...]
+Seg1_num=edges_tria(:,1);
+Seg2_num=edges_tria(:,2);
+Seg3_num=edges_tria(:,3);
+
+%value of data on each tips of the segments
+Data1=mask(Seg1);
+Data2=mask(Seg2);
+Data3=mask(Seg3);
+
+%get the ranges for each segment
+Range1=sort(Data1,2);
+Range2=sort(Data2,2);
+Range3=sort(Data3,2);
+
+%find the segments that contain this value
+pos1=(Range1(:,1)<level & Range1(:,2)>level);
+pos2=(Range2(:,1)<level & Range2(:,2)>level);
+pos3=(Range3(:,1)<level & Range3(:,2)>level);
+
+%get elements
+poselem12=(pos1 & pos2);
+poselem13=(pos1 & pos3);
+poselem23=(pos2 & pos3);
+poselem=find(poselem12 | poselem13 | poselem23);
+numelems=length(poselem);
+
+%if no element has been flagged, skip to the next level
+if numelems==0,
+	warning('contourlevelzero warning message: no elements found with corresponding level value in mask');
+	contours=struct([]);
+	return;
+end
+
+%go through the elements and build the coordinates for each segment (1 by element)
+x1=zeros(numelems,1);
+x2=zeros(numelems,1);
+y1=zeros(numelems,1);
+y2=zeros(numelems,1);
+edge_l=zeros(numelems,2);
+
+for j=1:numelems,
+
+	weight1=(level-Data1(poselem(j),1))/(Data1(poselem(j),2)-Data1(poselem(j),1));
+	weight2=(level-Data2(poselem(j),1))/(Data2(poselem(j),2)-Data2(poselem(j),1));
+	weight3=(level-Data3(poselem(j),1))/(Data3(poselem(j),2)-Data3(poselem(j),1));
+
+	if poselem12(poselem(j));
+
+		x1(j)=x(Seg1(poselem(j),1))+weight1*(x(Seg1(poselem(j),2))-x(Seg1(poselem(j),1)));
+		x2(j)=x(Seg2(poselem(j),1))+weight2*(x(Seg2(poselem(j),2))-x(Seg2(poselem(j),1)));
+		y1(j)=y(Seg1(poselem(j),1))+weight1*(y(Seg1(poselem(j),2))-y(Seg1(poselem(j),1)));
+		y2(j)=y(Seg2(poselem(j),1))+weight2*(y(Seg2(poselem(j),2))-y(Seg2(poselem(j),1)));
+		edge_l(j,1)=Seg1_num(poselem(j));
+		edge_l(j,2)=Seg2_num(poselem(j));
+
+	elseif poselem13(poselem(j)),
+
+		x1(j)=x(Seg1(poselem(j),1))+weight1*(x(Seg1(poselem(j),2))-x(Seg1(poselem(j),1)));
+		x2(j)=x(Seg3(poselem(j),1))+weight3*(x(Seg3(poselem(j),2))-x(Seg3(poselem(j),1)));
+		y1(j)=y(Seg1(poselem(j),1))+weight1*(y(Seg1(poselem(j),2))-y(Seg1(poselem(j),1)));
+		y2(j)=y(Seg3(poselem(j),1))+weight3*(y(Seg3(poselem(j),2))-y(Seg3(poselem(j),1)));
+		edge_l(j,1)=Seg1_num(poselem(j));
+		edge_l(j,2)=Seg3_num(poselem(j));
+
+	elseif poselem23(poselem(j)),
+
+		x1(j)=x(Seg2(poselem(j),1))+weight2*(x(Seg2(poselem(j),2))-x(Seg2(poselem(j),1)));
+		x2(j)=x(Seg3(poselem(j),1))+weight3*(x(Seg3(poselem(j),2))-x(Seg3(poselem(j),1)));
+		y1(j)=y(Seg2(poselem(j),1))+weight2*(y(Seg2(poselem(j),2))-y(Seg2(poselem(j),1)));
+		y2(j)=y(Seg3(poselem(j),1))+weight3*(y(Seg3(poselem(j),2))-y(Seg3(poselem(j),1)));
+		edge_l(j,1)=Seg2_num(poselem(j));
+		edge_l(j,2)=Seg3_num(poselem(j));
+	else
+		%it shoud not go here
+	end
+end
+
+%now that we have the segments, we must try to connect them...
+
+%loop over the subcontours
+contours=struct([]);
+
+while ~isempty(edge_l),
+
+	%take the right edge of the second segment and connect it to the next segments if any
+	e1=edge_l(1,1);   e2=edge_l(1,2);
+	xc=[x1(1);x2(1)]; yc=[y1(1);y2(1)];
+
+	%erase the lines corresponding to this edge
+	edge_l(1,:)=[];
+	x1(1)=[]; x2(1)=[];
+	y1(1)=[]; y2(1)=[];
+
+	[ro1,co1]=find(edge_l==e1);
+
+	while ~isempty(ro1)
+
+		if co1==1,
+			xc=[x2(ro1);xc]; yc=[y2(ro1);yc];
+
+			%next edge:
+			e1=edge_l(ro1,2);
+
+		else
+			xc=[x1(ro1);xc]; yc=[y1(ro1);yc];
+
+			%next edge:
+			e1=edge_l(ro1,1);
+		end
+
+		%erase the lines of this
+		edge_l(ro1,:)=[];
+		x1(ro1)=[]; x2(ro1)=[];
+		y1(ro1)=[]; y2(ro1)=[];
+
+		%next connection
+		[ro1,co1]=find(edge_l==e1);
+	end
+
+	%same thing the other way (to the right)
+	[ro2,co2]=find(edge_l==e2);
+
+	while ~isempty(ro2)
+
+		if co2==1,
+			xc=[xc;x2(ro2)]; yc=[yc;y2(ro2)];
+
+			%next edge:
+			e2=edge_l(ro2,2);
+		else
+			xc=[xc;x1(ro2)]; yc=[yc;y1(ro2)];
+
+			%next edge:
+			e2=edge_l(ro2,1);
+		end
+
+		%erase the lines of this
+		edge_l(ro2,:)=[];
+		x1(ro2)=[]; x2(ro2)=[];
+		y1(ro2)=[]; y2(ro2)=[];
+
+		%next connection
+		[ro2,co2]=find(edge_l==e2);
+	end
+
+	%save xc,yc contour: 
+	contours(end+1).x=xc;
+	contours(end).y=yc;
+	contours(end).name='';
+	contours(end).nods=length(xc);
+	contours(end).density=1;
+	contours(end).closed=0;
+
+end
Index: /issm/trunk-jpl/src/m/exp/expcontourlevelzero.m
===================================================================
--- /issm/trunk-jpl/src/m/exp/expcontourlevelzero.m	(revision 16517)
+++ /issm/trunk-jpl/src/m/exp/expcontourlevelzero.m	(revision 16517)
@@ -0,0 +1,13 @@
+function expcontourlevelzero(md,mask,level,filename)
+%EXPCONTOURLEVELZERO - write an Argus file from a structure recovered from running contourlevelzero 
+%
+%   Usage:
+%      expcontourlevelzero(md,mask,level,filename)
+% 
+%   Example:
+%      expcontourlevelzero(md,md.geometry.thickness,0, 'Level0.exp');
+%
+%   See also CONTOURLEVELZERO, EXPWRITE
+
+contours=contourlevelzero(md,mask,level);
+expwrite(contours,filename);