Hi all,
Firstly, thank you all so much for your hard work on this library.
For my brain teaser, I've searched through the docs and mailing list archives
awhile and am having a hard time putting together the steps I need to handle
this aggregation.
CFSR 1 hour data files data from here : http://rda.ucar.edu/datasets/ds094.0/
cdas_20161215_0000_f00000_G4.grib2
cdas_20161215_0000_f00100_G4
cdas_20161215_0000_f00200_G4
cdas_20161215_0000_f00300_G4
etc...
The hourly files declare 2 time dimensions, one with bounds set and another
without.
cdas_20161215_0000_f00300_G4.grib2
double time(time=1);
:units = "Hour since 2016-12-15T00:00:00Z";
:standard_name = "time";
:long_name = "GRIB forecast or observation time";
:calendar = "proleptic_gregorian";
:bounds = "time_bounds";
double time_bounds(time=1, 2);
:units = "Hour since 2016-12-15T00:00:00Z";
:long_name = "bounds for time";
double time1(time1=1);
:units = "Hour since 2016-12-15T00:00:00Z";
:standard_name = "time";
:long_name = "GRIB forecast or observation time";
:calendar = "proleptic_gregorian";
The problem is that when I step through each dataset creation, different hourly
files will swap names for the 2 time dimension names. So then
AggregationExisting is unable to find the dimension name 'time' for certain
files, e.g. on the u-component_of_wind_isobaric variable in the 0300 file
because it was swapped to time1 instead.
Time dimension name issue illustrated in 2 files:
//cdas_20161215_0000_f00300_G4.grib2
float u-component_of_wind_isobaric(time1=1, isobaric3=37, lat=361, lon=720);
:long_name = "u-component of wind @ Isobaric surface";
:units = "m/s";
:abbreviation = "UGRD";
:missing_value = NaNf; // float
:grid_mapping = "LatLon_Projection";
:coordinates = "reftime time1 isobaric3 lat lon ";
:Grib_Variable_Id = "VAR_0-2-2_L100";
:Grib2_Parameter = 0, 2, 2; // int
:Grib2_Parameter_Discipline = "Meteorological products";
:Grib2_Parameter_Category = "Momentum";
:Grib2_Parameter_Name = "u-component of wind";
:Grib2_Level_Type = "Isobaric surface";
:Grib2_Generating_Process_Type = "Forecast";
//cdas_20161215_0000_f00200_G4.grib2
float u-component_of_wind_isobaric(time=1, isobaric3=37, lat=361, lon=720);
:long_name = "u-component of wind @ Isobaric surface";
:units = "m/s";
:abbreviation = "UGRD";
:missing_value = NaNf; // float
:grid_mapping = "LatLon_Projection";
:coordinates = "reftime time isobaric3 lat lon ";
:Grib_Variable_Id = "VAR_0-2-2_L100";
:Grib2_Parameter = 0, 2, 2; // int
:Grib2_Parameter_Discipline = "Meteorological products";
:Grib2_Parameter_Category = "Momentum";
:Grib2_Parameter_Name = "u-component of wind";
:Grib2_Level_Type = "Isobaric surface";
:Grib2_Generating_Process_Type = "Forecast";
Code I'm calling:
List<String> variableNames =
Arrays.asList("u-component_of_wind_isobaric","u-component_of_wind_height_above_ground","v-component_of_wind_isobaric","v-component_of_wind_height_above_ground","Pressure_reduced_to_MSL_msl","Geopotential_height_isobaric");
NetcdfDataset netcdfDataset = new NetcdfDataset();
//here i'm trying to aggregate on a dimension called 'time'
AggregationExisting aggregationExisting = new
AggregationExisting(netcdfDataset, "time", null);
aggregationExisting.addDatasetScan(null,
"/cfsr-gribs/201612/",
"G4.grib2",
null,
null,
NetcdfDataset.getDefaultEnhanceMode(),
"false",
null);
aggregationExisting.persistWrite();
aggregationExisting.finish(new CancelTaskImpl());
GridDataset gridDataset = new GridDataset(netcdfDataset);
//....spline data in merged dataset in memory
//writer is the NetcdfFileWriter with the merged file path
writer.setRedefineMode(true);
CFGridWriter2.writeFile(gridDataset, variableNames,
gridDataset.getBoundingBox(), null, 1, null, null, 1, true, writer);
This is my first NetCDF library use so I'm shopping for some preprocessing
tools to get these datasets merged that have this quirk. Could I move all the
variables into the same time dimension and rename it, for instance? Even a link
to an example I missed would be helpful. Otherwise I'm guessing I will look
into manually declaring dimensions and using readDataSlice() to manually copy
in the data into a new merged file.
Thanks!
-Tom Hagman
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