Geopotential Height Map

http://www.nc-climate.ncsu.edu/images/climate/enso/geo_heights.php

Geopotential height maps is the elevation of a given air pressure. It approximates the true height of a pressure surface above a mean sea level. An example of geospatial height is when cold air is less dense than warm air; the pressure surfaces then tends to rise. This shows that heights are greater in warm air pockets.