Parse NcML

Back: AIS Using NcML

Since we are interested in only the part of NcML which adds attributes and variables to a data set, build a parser for those parts of NcML and ignore the parts for aggregation.

The NcML schema.

How to treat NcML elements relative to the DAP

Build a parser for these elements:

netcdf

The design of NcML is such that using it as an AIS - augmenting an existing dataset - is really exploiting one of its optional features. When the <netcdf> element has a netcdf@localtion attribute, then the NcML file is providing information that will augment the stuff in the data set named by location. The original NcML design intended for location to name a netCDF file, but we are going to generalize that to be any file served by the BES running this handler (for location that is a file:/ URL) or any remote Hyrax server (when location is a DAP URL).

In most uses foreseen for this handler, the netcdf@location attribute will always be present.

readMetadata

If present read the metadata from the data source and augment with the information supplied in this file. This will normally be present.

explicit

If present, retain only the variables from the data set named by netcdf@location and then add the information included here.