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Re: [ferret_users] micro-adjusting time

Title: Signature

Hi Bruno,

Thank you for the report. This is a spurious message for this dataset. When initializing a dataset, Ferret tests that all of the coordinate variables are monotonically increasing. A parameter in the internal code was being incorrectly initialized, and that triggered this false result on the test of the time axis. As you saw, in fact the time axis is increasing, and Ferret is not in fact doing any "micro-adjusting" as it stores the axis information.  We will get this fixed in the next release.

By the way for those who may not have run into this, if there were repeated values, for instance if we repeated the second value so that the timesteps are  600432, 600433, 600433, 600434; then Ferret would allow you to work with the dataset by applying this micro-adjusting,adding a small amount to the second of the repeated coordinate values:

yes? use repeated_t.nc
           *** NOTE: Axis has repeated values -- micro-adjusting time
yes? list/l=1:4/precision=12 t[gt=u]
             VARIABLE : T
                        axis TIME
             FILENAME : repeat.nc
             SUBSET   : 4 points (TIME)
 01-JUL-2018 00:00:00 / 1:  600432.000000
 01-JUL-2018 01:00:00 / 2:  600433.000000
 01-JUL-2018 01:00:00 / 3:  600433.000074
 01-JUL-2018 02:00:00 / 4:  600434.000000


On 10/19/2018 5:57 AM, Bruno Levier wrote:

Loading a netcdf file (in attachment of this email) with FERRET v7.43, I've got this warning:
use test.nc
*** NOTE: Axis has repeated values -- micro-adjusting time

But in fact the time variable has no repeated values at all.

This is the time variable listed by Ferret:
list /l=1:5 /pre=12 T[G=u]
             VARIABLE : T
                        axis TIME
             FILENAME : test.nc
             SUBSET   : 5 points (TIME)
 01-JUL-2018 00:00 /  1:  600432.000000
 01-JUL-2018 01:00 /  2:  600433.000002
 01-JUL-2018 02:00 /  3:  600434.000004
 01-JUL-2018 03:00 /  4:  600435.000006
 01-JUL-2018 04:00 /  5:  600436.000008

And this the time variable in the file:
ncks -C -H -v time test.nc | head -5

Any idea of what is going on?



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