function obstID=checkEdge(xE,yE,Obst)
%CHECKEDGE

obstID=0;
for i_obst=1:size(Obst,2),
        %determine lengths and angles
        [a,b,c,A,B,C]=cosinelaw([xE,Obst(1,i_obst)],[yE,Obst(2,i_obst)]);
        
        %determine shortest edge-obstacle distance
        if A>pi/2 || B>pi/2,        %vertices-obstacle distance
            d=min(a,b);
        else                        %perpendicular distance
            d=perpDist([xE,Obst(1,i_obst)],[yE,Obst(2,i_obst)]);
        end
        
        %check minimal distance
        if d<=Obst(3,i_obst),
            obstID=i_obst;
            break;
        end
end