This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.
> Full Name: Andrew Barkwith > Email Address: address@hidden > Organization: BGS > Package Version: 3.0u2 build date:2012-02-10 17:21 UTC > Operating System: Windows 7 > Hardware: Java: home: C:\Program Files\IDV_3.0u2\jre version: 1.6.0_20 > j3d:1.5.2 fcs (build4) > Description of problem: > > We are trying to open a NetCDF file, however it is throwing up the > following error. We are not sure what a CDM file is. > > Thanks, > Andy > Hi Andy, When the IDV opens a nc file, it will try to figure out the data type first if not specified by the end user. The CDM stands for Common Data Model, which is a nc data model in the Java world. To fit your data into this data model, you need to follow certain conventions, the common one is CF convention. If you can provide more information about the dataset you are working on and upload a sample file here, I can take a look. http://motherlode.ucar.edu/repository/alias/idvupload Yuan > > There was an error loading the data: > > Error creating data source:file.grid with: > F:\fflow\CEH_Version_of_HadRM3\National\PE\FF-HadRM3-afgcx_PE-1950-1979.nc > Grid data source failed making data set: > F:\fflow\CEH_Version_of_HadRM3\National\PE\FF-HadRM3-afgcx_PE-1950-1979.nc > > Cant read > F:/fflow/CEH_Version_of_HadRM3/National/PE/FF-HadRM3-afgcx_PE-1950-1979.nc: > not a valid CDM file. > > ****************** > Stack trace: > java.io.IOException: Cant read > F:/fflow/CEH_Version_of_HadRM3/National/PE/FF-HadRM3-afgcx_PE-1950-1979.nc: > not a valid CDM file. > at ucar.nc2.NetcdfFile.open(NetcdfFile.java:836) > at ucar.nc2.NetcdfFile.open(NetcdfFile.java:479) > at ucar.nc2.dataset.NetcdfDataset.openOrAcquireFile(NetcdfDataset.java:696) > at ucar.nc2.dataset.NetcdfDataset.openDataset(NetcdfDataset.java:424) > at ucar.nc2.dataset.NetcdfDataset.acquireDataset(NetcdfDataset.java:520) > at ucar.nc2.dt.grid.GridDataset.open(GridDataset.java:101) > at ucar.nc2.dt.grid.GridDataset.open(GridDataset.java:87) > at > ucar.unidata.data.grid.GeoGridDataSource.doMakeDataSet(GeoGridDataSource.java:1094) > at > ucar.unidata.data.grid.GeoGridDataSource.getDataset(GeoGridDataSource.java:1116) > at > ucar.unidata.data.grid.GeoGridDataSource.initAfterCreation(GeoGridDataSource.java:478) > at ucar.unidata.data.DataManager.createDataSource(DataManager.java:1577) > at > ucar.unidata.idv.IntegratedDataViewer.createDataSource(IntegratedDataViewer.java:1980) > at > ucar.unidata.idv.IntegratedDataViewer.makeDataSource(IntegratedDataViewer.java:1897) > at > ucar.unidata.idv.IntegratedDataViewer.makeDataSource(IntegratedDataViewer.java:1831) > at > ucar.unidata.idv.IntegratedDataViewer.makeDataSource(IntegratedDataViewer.java:1804) > at ucar.unidata.idv.chooser.IdvChooser.makeDataSource(IdvChooser.java:943) > at ucar.unidata.idv.chooser.FileChooser.selectFilesInner(FileChooser.java:656) > at ucar.unidata.idv.chooser.FileChooser.selectFiles(FileChooser.java:525) > at ucar.unidata.idv.chooser.FileChooser.doLoadInThread(FileChooser.java:547) > at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) > at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) > at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) > at java.lang.reflect.Method.invoke(Unknown Source) > at ucar.unidata.util.Misc$2.run(Misc.java:1062) > at ucar.unidata.util.Misc$3.run(Misc.java:1090) > > > Ticket Details =================== Ticket ID: GVP-275178 Department: Support IDV Priority: Normal Status: Open