Beginner's question- correction in matlab code for road detection from satellite images project

 for k = 1:length(lines)
   len = norm(lines(k).point1 - lines(k).point2);
   if (len > minlinelen)
    xy = [lines(k).point1; lines(k).point2];
    plot(xy(:,1),xy(:,2),'LineWidth',2,'Color','green');
% Plot beginnings and ends of lines
    plot(xy(1,1),xy(1,2),'.','LineWidth',2,'Color','yellow');
    start(k,1) = xy(1,1);
    start(k,2) = xy(1,2);
    plot(xy(2,1),xy(2,2),'.','LineWidth',2,'Color','red');
    end1(k,1) = xy(2,1);
    end1(k,2) = xy(2,2);
   end

In this lines of code, the output also includes the points where the start and end points are 0,0 i should somehow eliminate it by giving the condition that fr values greater than 0,0 i.e the values of k > 0... like that plese help me in this code.