Question
what contour line show?
Answers
Writeacher
http://www.google.com/search?q=contour+line&rls=com.microsoft:en-us:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7GGIE_en
and
http://images.google.com/images?q=contour%20line&rls=com.microsoft:en-us:IE-SearchBox&oe=UTF-8&sourceid=ie7&rlz=1I7GGIE_en&um=1&ie=UTF-8&sa=N&hl=en&tab=wi
and
http://images.google.com/images?q=contour%20line&rls=com.microsoft:en-us:IE-SearchBox&oe=UTF-8&sourceid=ie7&rlz=1I7GGIE_en&um=1&ie=UTF-8&sa=N&hl=en&tab=wi