Isobar Map

http://ww2010.atmos.uiuc.edu/(Gl)/guides/maps/sfcobs/cntr/wind.rxml

This image is an example of an Isobar map.  Isobar maps are used in weather for show the amount of pressure associated with low and high pressure weather systems usually measured in millibars.  The Black contour lines represent different levels of pressure, which are the purple numbers