Topographic Map

http://www.nh.nrcs.usda.gov/technical/topomaps.html

A topographic map is a map showing natural and/or physical features of a landscape, including altitude contours and so by means of countour lines. A reference point is used so that ground elevation or vertical elevation towards this point can be represented. Here the topographic map is the representation of an isolated hill. The reference point used is sea level