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

Whittington, Reed rwhittington at burnsmcd.com
Sun Nov 9 11:09:04 EST 2014


other data models like FME represent non spatial features with a null geometry field.  
Hope this helps.  

Sent from my iPad

> On Nov 9, 2014, at 7:19 AM, "Even Rouault" <even.rouault at spatialys.com> wrote:
> 
> 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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