Hi Nicolas,with ncdump you may have a look into your netcdf file. You will find that the time axis has units 'seconds' but with very large values, because of the choice of the time axis origin.
Ferret does many calculations in real*4, this implies 6 valid digits. I guess, something goes wrong with the axis setup for the second plot because of limited accuracy of calculations with small differences of large numbers.
One should generally avoid calculations based on small differences of large numbers not only with ferret.
As a test you may generate a new time axis. This is an example, for correct numbers - you know the details:
define axis/t=1:9:1/unit=days/t0=1-jan-2000 tax let temp1=temp[gt=tax@asn] ! Now the data are at a new time axis with set reg/i=4/j=3 set view upper plot/k=30 temp1 set view lower shade temp1 This should be the expected result - except the wrong time axis. Best, Martin Nicolas Perenne wrote:
Hello, I have a strange problem with the attached NetCDF file (generated by a numerical model, but this one is pretty small). Can't figure it out and was unable to find a clue in the mail archive. So this is about 'shade': a vertical slice through the attached NetCDF is fine in y-z but another in t-z doesn't show anything (cf 'pb.jnl' also attached to this mail). 'plot/k=30' is ok though, and moreover this is the first time I have such a problem with a t-z slice (doing quite a lot of it on various other datasets) Currently using Ferret V6.72 but same pb with an old (windows) V5.51. Do you think it could be a ferret bug, or a corruption of the NetCDF file, or a subtle combination of both? Thanks, Nicolas