[THREDDS #PQT-331819]: NetCDF Subset Service (NCSS) and UDUNITS: wrong datetimes for climatologies

ok i understand better. why do you use year = 0000 ?

> Hi THREDDS Support,
> Thanks for the follow-up. Nope, they don't fall at the start of each month,
> so that's not my concern. I just want them to match up with the dates that
> WMS (TDS > ncWMS) is giving me. Since they don't match up, I have no way of
> using the dates from one service to access the data/images from the other.
> Here's a comparison of the two:
> 
> TDS/NCSS/UDUNITS (left) vs. TDS WMS/ncWMS (right):
> 
> 0001-01-16T06:00:00Z, 0000-01-14T06:00:00.000Z
> 0001-02-15T16:29:05Z, 0000-02-13T16:29:05.999Z
> 0001-03-17T02:58:12Z, 0000-03-15T02:58:12.000Z
> 0001-04-16T13:27:18Z, 0000-04-14T13:27:18.000Z
> 0001-05-16T23:56:24Z, 0000-05-14T23:56:24.000Z
> 0001-06-16T10:25:30Z, 0000-06-14T10:25:30.000Z
> 0001-07-16T20:54:36Z, 0000-07-14T20:54:36.000Z
> 0001-08-16T07:23:42Z, 0000-08-14T07:23:42.000Z
> 0001-09-15T17:52:48Z, 0000-09-13T17:52:48.000Z
> 0001-10-16T04:21:54Z, 0000-10-14T04:21:54.000Z
> 0001-11-15T14:51:00Z, 0000-11-13T14:51:00.000Z
> 0001-12-16T01:20:05Z, 0000-12-14T01:20:05.999Z
> 
> Links for each of the above so you can see for yourself:
> 
> a csv dump from NCSS:
> http://oceanwatch.pifsc.noaa.gov/thredds/ncss/grid/climatologies/PF5_SST_Climatology_Monthly_1985_2001.nc?var=sst&latitude=21&longitude=-161&temporal=all&time_start=0001-01-16T06%3A00%3A00Z&time_end=0001-12-16T01%3A20%3A05Z&time=0001-01-16T06%3A00%3A00Z&vertCoord=&accept=csv&point=true
> 
> see Dimension "time" in WMS GetCapabilities:
> http://oceanwatch.pifsc.noaa.gov/thredds/wms/climatologies/PF5_SST_Climatology_Monthly_1985_2001.nc?service=WMS&version=1.3.0&request=GetCapabilities
> 
> So, it could be a "problem" with either TDS/udunits or ncWMS. Either way, I
> would like to see them match up so I don't have to hard-code a look-up
> table. Thanks for listening.
> Cheers,
> John
> 
> address@hidden> wrote:
> 
> > Hi John:
> >
> > im seeing this coordinate:
> >
> >   double TIME(TIME=12);
> >     :units = "hour since 0000-01-01 00:00:00";
> >     :time_origin = "1-JAN-0000 00:00:00";
> >     :modulo = " ";
> >
> > the values are:
> >
> > hour since 0000-01-01 00:00:00
> > TIME =
> >  {366.0, 1096.485, 1826.97, 2557.455, 3287.94, 4018.425, 4748.91, 5479.395,
> > 6209.88, 6940.365, 7670.85, 8401.335}
> >
> > giving dates:
> >
> >  0001-01-01 00:45:27Z
> >  0001-01-31 11:14:33Z
> >  0001-03-01 21:43:39Z
> >  0001-04-01 08:12:45Z
> >  0001-05-01 18:41:51Z
> >  0001-06-01 05:10:57Z
> >  0001-07-01 15:40:02Z
> >  0001-08-01 02:09:09Z
> >  0001-08-31 12:38:15Z
> >  0001-09-30 23:07:21Z
> >  0001-10-31 09:36:27Z
> >  0001-11-30 20:05:33Z
> >  0001-12-31 06:34:38Z
> >
> > presumably you really want these to be the start of each month ?
> >
> > > Hi TDS and UDUNITS Folks,
> > > Just noticed the following bug: for monthly climatologies where the year
> > is
> > > set to "0000", NetCDF Subset Service (NCSS) is erroneously showing a year
> > of
> > > 0001. Here's the result of an AVHRR SST monthly climatology in NCSS:
> > >
> > >
> > http://oceanwatch.pifsc.noaa.gov/thredds/ncss/grid/climatologies/PF5_SST_Climatology_Monthly_1985_2001.nc?var=sst&latitude=21&longitude=-161&temporal=all&time_start=0001-01-16T06%3A00%3A00Z&time_end=0001-12-16T01%3A20%3A05Z&time=0001-01-16T06%3A00%3A00Z&vertCoord=&accept=csv&point=true
> > >
> > > date,lat[unit="degrees_north"],lon[unit="degrees_east"],sst[unit="degrees
> > > Celsius"]
> > > 0001-01-16T06:00:00Z,21.0,-161.0,24.6
> > > 0001-02-15T16:29:05Z,21.0,-161.0,24.45
> > > 0001-03-17T02:58:12Z,21.0,-161.0,24.375
> > > 0001-04-16T13:27:18Z,21.0,-161.0,24.45
> > > 0001-05-16T23:56:24Z,21.0,-161.0,25.125
> > > 0001-06-16T10:25:30Z,21.0,-161.0,25.875
> > > 0001-07-16T20:54:36Z,21.0,-161.0,26.475
> > > 0001-08-16T07:23:42Z,21.0,-161.0,27.0
> > > 0001-09-15T17:52:48Z,21.0,-161.0,27.225
> > > 0001-10-16T04:21:54Z,21.0,-161.0,27.15
> > > 0001-11-15T14:51:00Z,21.0,-161.0,26.325
> > > 0001-12-16T01:20:05Z,21.0,-161.0,25.2
> > >
> > >
> > > If you list the time variable with OPeNDAP, you get the following
> > > (units = "hour since 0000-01-01 00:00:00"):
> > >
> > >
> > http://oceanwatch.pifsc.noaa.gov/thredds/dodsC/climatologies/PF5_SST_Climatology_Monthly_1985_2001.nc.ascii?TIME[0:1:11]
> > >
> > > Dataset {
> > > Float64 TIME[TIME = 12];
> > > } climatologies/PF5_SST_Climatology_Monthly_1985_2001.nc;
> > > ---------------------------------------------
> > > TIME[12]
> > > 366.0, 1096.485, 1826.97, 2557.455, 3287.94, 4018.425, 4748.91,
> > > 5479.395, 6209.88, 6940.365, 7670.85, 8401.335
> > >
> > >
> > > Running the above numbers through udunits, it seems the problem is
> > actually
> > > with udunits:
> > >
> > >
> > > > udunits
> > > You have: 366 hour since 0000-01-01 00:00:00
> > > You want:
> > > Definition: "1317600 seconds since 1-01-01 00:00:00.00 UTC"
> > > "366 hour since 0000-01-01 00:00:00" is 1-01-16 06:00:0 UTC
> > >
> > >
> > > It lists the year simply as "1". In contrast, ncWMS/Godiva2 correctly
> > > identifies the dates as belonging to year 0000:
> > >
> > >
> > http://oceanwatch.pifsc.noaa.gov/thredds/godiva2/godiva2.html?server=http://oceanwatch.pifsc.noaa.gov/thredds/wms/climatologies/PF5_SST_Climatology_Monthly_1985_2001.nc
> > >
> > > Thanks for your attention to this detail. A further note of interest is
> > that
> > > NCSS does not handle milliseconds, so in my application I'm having to
> > round
> > > to seconds and hope I get a result.
> > > Cheers,
> > > John Maurer
> > > Pacific Islands Ocean Observing System (PacIOOS)
> > > University of Hawaii at Manoa
> > >
> > >
> >
> >
> > Ticket Details
> > ===================
> > Ticket ID: PQT-331819
> > Department: Support THREDDS
> > Priority: Normal
> > Status: Open
> >
> >
> 
> 


Ticket Details
===================
Ticket ID: PQT-331819
Department: Support THREDDS
Priority: Normal
Status: Open