Le 18/01/13 11:31, Adam Estrada a écrit :
Spot on with Tika being an SIS dependency, Martin! The idea is to be able
to extract content from as may file formats as possible based on their MIME
types. GDAL provides the interface to a lot more geospatial formats.
We have the notion of "data source" interface (not yet committed), and
Tika or GDAL can be one of them. GeoTIFF, NetCDF, etc. are other data
sources (we have some extra flexibility if we read NetCDF files directly
rather than through GDAL for instance, but we would do that only for the
most important formats instead than duplicating the totality of GDAL).
However "data sources" appear downstream relative to metadata and other
basic modules. A list of modules in approximative dependency order can be:
- utility
- metadata
- referencing
- geometry
- feature
- coverage
- data source <-- Tika/GDAL can be plugged here
- styles
- renderer
I'm not sure if "filter" would be before or after "data source" - Johann
Sorel would known better (I think he is watching this list, even if he
didn't sent emails yet).
Actually the "sis-metadata" module being built is not about arbitrary
metadata, but rather about the "lingua franca" to be used in SIS for
metadata. Many metadata model could be choose for this purpose, but the
proposed SIS approach is to select ISO standards as the lingua franca.
All other sources of metadata would need to be converted to ISO 19115
before to be used in a source-independent way by all SIS modules. This
is the purpose for instance of the NetCDF - ISO mapping mentioned in
previous email. This explain why "data source", which is where
input/output happen, is so far away from metadata in the above
dependency chain; all preceding modules define the models which will
represent the data read by the data sources.
Obviously the XML (un)marshalling is an exception to what I just said,
since it is defined straight in the core metadata module instead than as
a data source. But we should have (I hope) few such exceptions. This
exception exists for two reasons: 1) as a side effect of the way JAXB
works (annotations straight in the source code), and 2) because while
ISO 19115 would be the "lingua franca" for the conceptual model, XML is
the "lingua franca" for the file format at least at OGC/ISO/INSPIRE, so
maybe it deserves that special treatment...
Martin
