Extreme values multiple files

[Paul emck]

Dear GrADS users,

Why would

'd min(air.2,t=1,t=365)'

only work fine with the default file (here file 2 - set dfile 2) and not
with other, aquivalent sdf-opened files? (Netcdf).
(air.n being files with daily temps of one year, it produces a map with the
annual's min temps).

What is missing in this expression to display other air.n correctly? I've
tried it with

'd min(air.2(z=1),t=1,t=365)'

hence addressing the level (a suggestion somewhere in this forum) but to no
avail.

-error message in graph "entire grid undefined"
-Data Request Warning:  Request beyond file limits
  Entire grid contents are set to missing data
  Dimension ranges are:  X = 1 144  Y = 1 73  Z = 1 17  T = -729390 365

especially "T = -729390 365" is a bit puzzling.

Goal is a somewhat more complex expression so changing the default file is
no option.

Thanks a lot!

GrADS: v1.8SL10 32-bit little-endian (though it is certainly due to limited
programming skills rather then GrADS issues).