[Geopackage] Historical question on metadata

Paul Daisey pdaisey1331 at gmail.com
Mon Jun 4 17:32:27 EDT 2018


Barry:

     Sorry, I don't have a sample GeoPackage that addresses the metadata 
issue.   I'm retired, no longer have work data on my laptop, and my 
archive DVDs are in the attic.  If you already have generated an XML 
metadata doc that validates according to ISO 19115 schemas, all you need 
do is insert it into a GPKG metadata table record column, with the 
mime_type column value "text/xml", a md_standard_uri column value 
pointing to the public 19115 XML Schema, and the md_scope column value 
set to the appropriate value, probably "dataset", assuming it applies to 
the entire GPKG.  If that is the case, then you also need a 
metadata_reference table record with a reference_scope column value of 
"geopackage" that refers to the metadata table record id column value in 
the md_file_id column, and with table_name, column_name, row_id_value 
and md_parent_id column values of NULL.

     If you want to add additional metadata records (perhaps from 
another source?) that only apply to particular subsets of geopackage 
data, and that amend or supplement the record above, then the 
metadata_reference table records for those metadata documents should 
refer to the metadata table record id above in the md_parent_id column 
value, and the other column values set to specify the data subsets 
described.

     I hope that helps.  If you have other particular questions, I'll 
try to answer them.

Paul


On 6/3/2018 2:09 PM, Barry O'Rourke wrote:
>
> Hello Paul, Jeff,
>
> We have also been investigating techniques for generating and 
> utilizing GeoPackage metadata. Our first workflow provides a user with 
> the ability to create an ISO 19115 metadata document that describes 
> the GeoPackage overall. The user can then publish this ISO 19115 
> metadata document into a service registry and provide other users with 
> the ability to discover GeoPackages of interest using a catalog search 
> and determine suitability of use.
>
> We are also storing this metadata as an XML document in a relational 
> table within the GeoPackage itself.
>
> Paul, we are very interested in investigating how you are using ISO 
> 19115 to describe "data" within the GeoPackage. Do you have a sample 
> GeoPackage we could work with?
>
> How are we planning to document these approaches and make them 
> available for discussion?
>
> Thanks,
>
> Barry
>
>
> On 4/20/2018 6:52 PM, Jeff Yutzler via Geopackage wrote:
>> OK, I get it now. I haven't actually seen an example of many-to-many 
>> metadata in the wild so I didn't know that was possible.
>> -Jeff
>>
>> On Fri, Apr 20, 2018 at 3:51 PM, Paul Daisey via Geopackage 
>> <geopackage at lists.opengeospatial.org 
>> <mailto:geopackage at lists.opengeospatial.org>> wrote:
>>
>>     All:
>>
>>         Pepijn has it right; the GeoPackage v1.0 metadata model had
>>     two tables following a common relational database design for
>>     implementing many to many relationships, which were needed to
>>     implement the hierarchical metadata model defined in ISO 19115. 
>>     One metadata record can apply to many data items (tables / rows /
>>     columns or any subset thereof), and one data item can be
>>     described by many metadata records (e.g. from different sources).
>>
>>         Cheers,
>>
>>     Paul Daisey
>>
>>
>>     On 4/20/2018 3:19 PM, Pepijn Van Eeckhoudt via Geopackage wrote:
>>>     Hi Jeff,
>>>
>>>     Which tables do you mean exactly? gpkg_metadata and
>>>     gpkg_metadata_reference?
>>>
>>>     One stores the metadata itself; the other is the association
>>>     relationship between the metadata and the data it describes.
>>>     Splitting the two allows reuse of metadata for multiple tables.
>>>
>>>     If I remember correctly, Paul Daisy did most of the work on
>>>     metadata so he might be able to give you a better answer.
>>>
>>>     Pepijn
>>>
>>>>     On 20 Apr 2018, at 21:10, Jeff Yutzler via Geopackage
>>>>     <geopackage at lists.opengeospatial.org
>>>>     <mailto:geopackage at lists.opengeospatial.org>> wrote:
>>>>
>>>>     Hello list.
>>>>     Does anyone out there remember why we have two separate
>>>>     metadata tables as part of the Metadata Extension (this was
>>>>     originally part of core)? I am trying to produce guidance for
>>>>     this extension and as far as I can tell, there is a 1:1 mapping
>>>>     between the two tables. Am I missing something?
>>>>     -Jeff
>>>>
>>>>     -- 
>>>>     Jeff Yutzler
>>>>     Image Matters LLC <http://www.imagemattersllc.com/>
>>>>     Mobile: (703) 981-8753
>>>
>>
>>     -- 
>>     Paul Daisey 301-651-7148
>>
>>
>>
>>
>> -- 
>> Jeff Yutzler
>> Image Matters LLC <http://www.imagemattersllc.com/>
>> Mobile: (703) 981-8753
>

-- 
Paul Daisey 301-651-7148

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