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Hi Heiko: It was indeed a bug in the CDM. Now fixed with a pull request on 4.6. Thanks for reporting. John On Fri, Aug 28, 2015 at 2:56 AM, Heiko Klein <Heiko.Klein@xxxxxx> wrote: > Hi Bob, > > I totally agree that our files must be CF-compliant. But we want to be > able to read the files with most programs, and the whole CF can be > difficult to implement. The change I made is still CF compliant and it > works with the netcdf-java, too. Yes, netcdf-java only implements a > subset of CF, but since I'm not funding them, I can live with that subset. > > Writing a special format is usually simple (and we have some flexibility > within CF), reading all formats is hard, so we're trying to find a > compromise. > > > BTW since you have a NOAA email address: we started from the NOAA > templates: > > https://geo-ide.noaa.gov/wiki/index.php?title=NODC_NetCDF_Trajectory_Template > (and eliminated some conflicts with CF from them, e.g. axis) > > > Best regards, > > Heiko > > > On 2015-08-27 21:21, Bob Simons - NOAA Federal wrote: > > I'm not following this closely, but I was bothered by "we now know how > > to create a netcdf-java compliant trajectory file". netcdf-java is just > > one tool. There are other tools now, and there will be more in the > > future. netcdf-java probably supports a subset/superset of the file > > types defined by the CF DSG standard (which allows a huge number of > > minor variations). > > > > I think a far better goal is to seek to make files which are compliant > > with the CF DSG standard, and thus with any tool that follows the CF DSG > > standard. If a given tool (e.g., netcdf-java) can't deal with a valid CF > > DSG file, then it is a bug in that tool and you can > > legitimately/reasonably ask the developer to fix the bug. > > > > On Thu, Aug 27, 2015 at 12:01 PM, Heiko Klein <Heiko.Klein@xxxxxx > > <mailto:Heiko.Klein@xxxxxx>> wrote: > > > > Hi Kyle, > > > > I made now the time-dimension 2-dimensional, i.e. time(obs, > trajectory), > > removing the one simplification made below. netcdf-java seems now to > be > > able to read the trajectories. Since the page: > > > http://www.unidata.ucar.edu/software/thredds/current/netcdf-java/reference/FeatureDatasets/CFpointImplement.html > > already mentions differences from CF, maybe this one could be entered > > there, too? (Or maybe it's easy to extend the cdm to support > > one-dimensional time-axes?) > > > > > > > > I wasn't able to plot trajectories as seen in netcdf-java 2.2. Is it > > just me not finding the right buttons or was this feature removed? > This > > is not critical, but would be nice for debugging. > > > > > > But the most important point is that we now know how to create a > > netcdf-java compliant trajectory file. Thanks for your help. > > > > Heiko > > > > > > On 2015-08-27 20:17, Heiko Klein wrote: > > > Hi Kyle, > > > > > > we're trying to use quite strictly H.4.1 here, with one addition: > > > > > > Since all trajectories have the same timesteps we use 'time'='obs' > and > > > we don't have a special obs dimension. According to CF, this is > > allowed: > > > (Chapter H.4.1: "If the trajectories all have the same set of > > times, the > > > time auxiliary coordinate variable could be one-dimensional > time(obs), > > > or replaced by a one-dimensional coordinate variable time(time), > > where > > > the size of the time dimension is now equal to the number of > > elements of > > > each trajectory. In the latter case, listing the time coordinate > > > variable in the coordinates attribute is optional.") > > > > > > Best regards, > > > > > > Heiko > > > > > > > > > On 2015-08-27 16:22, Kyle Wilcox wrote: > > >> Hi Heiko, > > >> > > >> At first glace, I can't figure out which CF specification you were > > >> trying to adhere to: H.4.1, H.4.2, H.4.3, or H.4.4. It appears > > you may > > >> have tried to adopt H.4.2 to use multiple trajectories, which I'm > not > > >> sure is supported in NetCDF-Java. > > >> > > >> Take a look at these Trajectory > > >> examples: > > > https://github.com/asascience-open/CFPointConventions/tree/master/trajectory > . > > >> Each folder contains a .cdl, .nc (that will load into > > NetCDF-Java), and > > >> an .ncml file. > > >> > > >> Hope that helps, > > >> Kyle > > >> > > >> > > >> On Thu, Aug 27, 2015 at 4:21 AM, Heiko Klein <Heiko.Klein@xxxxxx > > <mailto:Heiko.Klein@xxxxxx> > > >> <mailto:Heiko.Klein@xxxxxx <mailto:Heiko.Klein@xxxxxx>>> wrote: > > >> > > >> Hi, > > >> > > >> I'm trying to read trajectory data with netcdf-java. I've > > seen figures > > >> of this with netcdf-java 2.2 at > > >> > > >> > > > https://www.unidata.ucar.edu/software/thredds/v4.3/netcdf-java/tutorial/PointDatatype.html > > >> > > >> but both netcdf-4.6 and CF-1.6 have a different layout for > > >> trajectory data. > > >> > > >> > > >> > > >> I've tried now to generate a netcdf/CF file following the > > guidelines at > > >> > > > http://www.unidata.ucar.edu/software/thredds/current/netcdf-java/reference/FeatureDatasets/CFpointImplement.html > > >> (see attached file). > > >> > > >> > > >> ToolsUI gives me a 'CoordSys' with trajectory, time, lat, lon > and > > >> time,lat,lon have the expected axisTypes. Using FeatureScan, > > I get a > > >> coverage of 'Swath(T,Y,X): trajectory', which looks ok, but I > > get also > > >> an error message: > > >> > > >> --------- > > >> /home/heikok/openoil2.nc4 > > >> NetCDF-4 > > >> map = 'f:D(2)->R(4)' > > >> > > >> null > > >> > > >> CoverageFactory for '/home/heikok/openoil2.nc4' > > >> coverage = Swath > > >> FeatureDatasetFactoryManager errlog = Table > > >> PsuedoStructure(trajectory)/MultidimPseudo(trajectory,time) > > featureType > > >> TRAJECTORY: lat/lon/time coord not found > > >> **Failed to find FeatureDatasetFactory for= > > /home/heikok/openoil2.nc4 > > >> datatype=TRAJECTORY > > >> ---------- > > >> > > >> > > >> According to 'CoordSys', lat/lon/time are availble. > > >> > > >> The PointFeature/TRAJECTORY wasn't then able to plot the > > data. Any idea > > >> how I can correct my data to enable plotting in netcdf-java > UI? > > >> > > >> > > >> Best regards, > > >> > > >> Heiko > > >> > > >> > > >> > > >> _______________________________________________ > > >> netcdf-java mailing list > > >> netcdf-java@xxxxxxxxxxxxxxxx > > <mailto:netcdf-java@xxxxxxxxxxxxxxxx> > > <mailto:netcdf-java@xxxxxxxxxxxxxxxx > > <mailto:netcdf-java@xxxxxxxxxxxxxxxx>> > > >> For list information or to unsubscribe, visit: > > >> http://www.unidata.ucar.edu/mailing_lists/ > > >> > > >> > > > > > > > _______________________________________________ > > netcdf-java mailing list > > netcdf-java@xxxxxxxxxxxxxxxx <mailto:netcdf-java@xxxxxxxxxxxxxxxx> > > For list information or to unsubscribe, visit: > > http://www.unidata.ucar.edu/mailing_lists/ > > > > > > > > > > -- > > Sincerely, > > > > Bob Simons > > IT Specialist > > Environmental Research Division > > NOAA Southwest Fisheries Science Center > > 99 Pacific St., Suite 255A (New!) > > Monterey, CA 93940 (New!) > > Phone: (831)333-9878 (New!) > > Fax: (831)648-8440 > > Email: bob.simons@xxxxxxxx <mailto:bob.simons@xxxxxxxx> > > > > The contents of this message are mine personally and > > do not necessarily reflect any position of the > > Government or the National Oceanic and Atmospheric Administration. > > <>< <>< <>< <>< <>< <>< <>< <>< <>< > > > > -- > Dr. Heiko Klein Norwegian Meteorological Institute > Tel. + 47 22 96 32 58 P.O. Box 43 Blindern > http://www.met.no 0313 Oslo NORWAY > > _______________________________________________ > netcdf-java mailing list > netcdf-java@xxxxxxxxxxxxxxxx > For list information or to unsubscribe, visit: > http://www.unidata.ucar.edu/mailing_lists/ >
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