Hi Daniele,
Did you have any more comments on my last email? Would it make sense to
convert all Strings to Dates, and sort them , in order to find the
minimum and maximum? Isn't that a bit expensive (and repetitive) for
those two methods (you'd be doing it twice while doing it once provides
all info)? should we perhaps convert and sort all values once and store
them that way? But that may cause other unwanted side effects if they
are not in the same order any more as they are in the netcdf-java
objects (I am not that familiar with the code yet).
Actually, I am now thinking, the fault lies actually with both geotools
and netcdf-java.
* geotools should be taking into account that the time values might be
decreasing rather than increasing and should thus, just like
CoordinateAxis1D.java#L286
<https://github.com/Unidata/thredds/blob/5.0.0/cdm/src/main/java/ucar/nc2/dataset/CoordinateAxis1D.java#L286>,
take the maximum/minimum of both _extremes_.
* I think netcdf-java, *at the moment of aggregation, *should aggregate
the different files in the right order (be it increasing or decreasing).
I have sent an email to their email list about that.
Do you agree? What are your thoughts?
Regards
Niels
On 28-09-16 13:44, Niels Charlier wrote:
Yeah, still that implies that the order of the files specified in the
aggregation must be the same as the order of values for the aggregated
dimension inside those files themselves. I can find no such
specification though, but maybe I am missing it. It seems that in the
examples on
http://www.unidata.ucar.edu/software/thredds/current/netcdf-java/ncml/Aggregation.html,
the files are always specified in order.
Otherwise we have to the rather expensive operation of going through
all of the Strings,convert them to Dates, then find the
minimum/maximum for each time getMimimum() and getMaximum() is called.
But then again, I wonder if we shouldn't do the same for non-time
values (regular CoordinateValue).
What do you think?
Regards
Niels
On 28-09-16 11:41, Daniele Romagnoli wrote:
Hi Niels,
On Wed, Sep 28, 2016 at 11:05 AM, Niels Charlier <ni...@scitus.be
<mailto:ni...@scitus.be>> wrote:
On 23-09-16 17:03, Daniele Romagnoli wrote:
I think that once the aggregation is in place, times can be in
any order as you reported, so I think it's time to revisit the
timeVariable min/max computation (not sure there are other
methods around based on that supposition. I didn't check it yet).
Although, it seems that in netcdf-java's
CoordinateAxis1D.getMinValue() en CoordinateAxis1D.getMaxValue(),
an assumption is made that the extremes are at the beginning and
end.
Good catch. Are you referring to this?
https://github.com/Unidata/thredds/blob/5.0.0/cdm/src/main/java/ucar/nc2/dataset/CoordinateAxis1D.java#L286
https://github.com/Unidata/thredds/blob/5.0.0/cdm/src/main/java/ucar/nc2/dataset/CoordinateAxis1D.java#L295
It does take into account the order may be decreasing as well as
increasing, but not random.
Perhaps we should remain consistent with that?
I would say yes.
Cheers,
Daniele
Regards
Niels
--
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