Exercise using contour plots

Using data (presssure, height, temp, dewpoint, wind direction and speed) in

~lecjm/public_html/Teaching/IDL_course/Data/larkhill290605_0800_p.DAT
~lecjm/public_html/Teaching/IDL_course/Data/larkhill290605_0900_p.DAT
~lecjm/public_html/Teaching/IDL_course/Data/larkhill290605_1100_p.DAT
~lecjm/public_html/Teaching/IDL_course/Data/larkhill290605_1400_p.DAT
~lecjm/public_html/Teaching/IDL_course/Data/larkhill290605_1600_p.DAT

plot a single time (x-axis) height (y-axis) contour plot of dewpoint (shaded) and potential temperature (line contours, labelled).