Contour plot from Irregular Data Set

I'm newbie on visad programing, and I´m not know how to draw a contour 
plot from a set of irregular data set. I have a some meteorological 
stations in (lat,lon) format and i need to plot a contour of Maximum 
temperature.

Thanks in advance for any help.
Antonio S. Cofiño Gonzalez
Dpto. of Applied Mathematis And Computacional Sciencie
University of Cantabria -
Spain