Isotachs

Isotachs are used to show wind speed on a map. The isotachs on this map of Florida are measured in intervals of 10 knots.
http://weather.cod.edu/help/700tach.gif

Isobars

This is a map that makes the use of isobars. Each isobar represents the air pressure within the particular areas represented. http://www.newmediastudio.org/DataDiscovery/Hurr_ED_Center/Hurr_Structure_Energetics/Closed_Isobars/Closed_Isobars_fig02.jpg