Hypsography, most likely you’ve used this in your practice but called it topography.http://www.merriam-webster.com/dictionary/hypsographyhttp://www.cares.missouri.edu/projects/completed/hypso.aspx http://www.fws.gov/stand/standards/dl_hypso_WWW.htmlhttps://www.e-education.psu.edu/natureofgeoinfo/c7_p7.html/a>http://en.wikipedia.org/wiki/Elevation