True or False to plot this field. Removing the line
from the table has the same effect as F. If the user
requests a cross section plot, the letter is X. If
the user requests a plot on pressure level, the first
2 characters are TP, followed by the pressure value
(TP500 is 500 mb level); if the user requests a plot
on isentropic surface, the first 2 characters are
TI, followed by the potential temperature value (TI330
is 330 K level). The last two options only work with
? data.