[Geopackage] gpkg_contents when type is not 'feature' or 'tiles'

Even Rouault even.rouault at spatialys.com
Fri Nov 7 11:31:25 EST 2014


Forwarding the question/observation to Robert Coup & Ryan Lewis

But I guess that putting a new value in the data_type column of gpkg_contents 
makes that the whole geopackage must support the extension, i.e. must be able 
to deal with a value that is neither 'features' nor 'tiles'.

Le vendredi 07 novembre 2014 17:26:10, Pepijn Van Eeckhoudt a écrit :
> Cool, that's the first public extension in the wild that I know of.
> 
> Even, is it the intention that this gets applied to the entire
> geopackage (table_name == NULL)? Or should it be applied only to the
> aspatial tables themselves (and perhaps any feature tables that have a
> foreign reference to the aspatial table)?
> Applying a read-write extension to the entire geopackage means that
> applications that don't recognize the extension will most likely reject
> the geopackage as a whole; not just the tables that aren't supported.
> 
> Pepijn
> 
> On 07/11/14 16:52, Even Rouault wrote:
> > Le vendredi 07 novembre 2014 16:45:37, Pepijn Van Eeckhoudt a écrit :
> >> Hi Patrick,
> >> 
> >> There was a very similar question on the mailing list some time ago
> >> (look for thread 'Aspatial Tables with Metadata').
> >> Two strategies were proposed then:
> >> - Register the table as 'features' and apply a 'no geometry' extension
> >> to it - Register the table as 'aspatial'
> >> 
> >> I'm not sure which approach the person asking the question end up
> >> taking.
> > 
> > --> aspatial extension: http://www.gdal.org/geopackage_aspatial.html
> > 
> >> Pepijn
> >> 
> >> On 06/11/14 12:14, Patrick van Dijk wrote:
> >>> Hi,
> >>> 
> >>> I'd like to register my alpha only table (e.g. no geometry field)
> >>> table in gpkg_contents as I can then store an identifier
> >>> and description for the table and I can also add additional field
> >>> information in gpkg_data_columns.
> >>> 
> >>> So my suggestion is to create a gpkg_contents record with its
> >>> data_type set to 'alpha' (instead of feature).
> >>> 
> >>> Req 13 explains the gpkg_contents table for field data_type.
> >>> 
> >>> Type of data stored in the table:.
> >>> “features” per clause 2.1.2.1.1,
> >>> “tiles” per clause 2.2.2.1.1, or
> >>> an implementer-defined value
> >>> for other data tables in an
> >>> Extended GeoPackage.
> >>> 
> >>> So I guess, what I want to do is fine.
> >>> 
> >>> Am I right?
> >>> 
> >>> Patrick

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