[thredds] Using the NC4 String type for a variable containing a "cf_role" attribute

• To: thredds@xxxxxxxxxxxxxxxx
• Subject: [thredds] Using the NC4 String type for a variable containing a "cf_role" attribute
• From: Kyle Wilcox <kyle@xxxxxxxxxxxxxxx>
• Date: Thu, 12 Dec 2013 15:27:21 -0500

I have two files where the only difference is the variable type of the
"feature_type_instance" variable.

When using a Char array, it works just fine.
When using a String, NCJ fails to find a StructureRecord:

java.lang.IllegalStateException: Cant find Structure record
    at
ucar.nc2.ft.point.standard.Table$TableStructure.<init>(Table.java:253)
    at ucar.nc2.ft.point.standard.Table.factory(Table.java:110)
    at ucar.nc2.ft.point.standard.NestedTable.<init>(NestedTable.java:98)
    at
ucar.nc2.ft.point.standard.TableAnalyzer.analyze(TableAnalyzer.java:406)
    at
ucar.nc2.ft.point.standard.TableAnalyzer.factory(TableAnalyzer.java:294)
    at
ucar.nc2.ft.point.standard.PointDatasetStandardFactory.isMine(PointDatasetStandardFactory.java:114)
    at
ucar.nc2.ft.FeatureDatasetFactoryManager.wrap(FeatureDatasetFactoryManager.java:272)
    at
ucar.nc2.ft.FeatureDatasetFactoryManager.open(FeatureDatasetFactoryManager.java:243)

You can try loading each file into the FeatureTypes/PointFeature tab to see
the stacktrace from the String file (I've attached them).

Based on CF docs (
http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.6/cf-conventions.html#coordinates-metadata)
it states:
"The variable carrying the cf_role attribute may have any data type."


Is this a bug in NCJ?

Thanks,
Kyle

Attachment: char_type.nc
Description: Cdf file

Attachment: string_type.nc
Description: Cdf file

• Follow-Ups:
  • Re: [thredds] Using the NC4 String type for a variable containing a "cf_role" attribute
    • From: John Caron