[eml-dev] Additional FGDC to EML differences

[Matt Jones]

Hi Inigo,

Thanks for pointing this stuff out to us.  When Peter McCartney originally
implemented the spatial* parts of EML, I know he intended it to include all
of the information that could be contained in various versions of the FGDC
standards (CSDGM, BDP, and ESRI) that were available at the time, as well as
other fields from the then emerging ISO 19115 spec.  Are the fields you
mention in FGDC from the CSDGM/BDP? Or from the ESRI version?  If the
latter, then they might be recent additions that we should consider adding
to EML.   Do you think that we should file a bug against a future EML
version to add these fields?  I'm not very familiar with the spatial data
sections of EML, so I'd have to carefully examine all of the specs to
determine the overlap.  Sounds like you may have already done so?  If so,
could you file a bug against EML 2.2.0 if you think it is needed?

Thanks,
Matt

On Mon, Dec 14, 2009 at 1:53 PM, Inigo San Gil
<isangil at canyon.lternet.edu>wrote:

>
> Jessica,
>
> The issue 2) is normal -- no worries about duplicating the definition,
> it is a requirement of EML (to have a definition in a "nominal, textual
> type" attribute. Often the definition coincides with the attribute
> description, specially if the original metadata lacks further detail.
>
> on 3), it gets complicated.  EML is not strong on relationships,
> and the attempts to describe database connections, constraints and
> views are not quite applicable here.
>
> But before elaborating, let me address the last point of 3)
>
> You say
>
> *See lines 871 through 880 on the FGDC xml file.*
>
>  - *detailed* – Detailed Description.  Description of the entities,
>  attributes, attribute values, and related characteristics encoded in the
>  dataset.
>  - *enttyp* – Entity Type.  The definition and description of a set into
>  which similar entity instances are classified.
>  - *enttypt* – Entity Type Count.  The number of objects that the entity
>  contains.  For example, the number of features contained by a feature
>  class or the number of rows contained by a table.
>
>
> Problem there is that EML needs also (mandatory-enforced by Metacat) the
> "attribute List".  These entities do not provide a list of attributes, so
> they are
> not processed. It seems that these entities are just relationships, may be
> Joiner
> tables, but I cannot tell details.  I wouldnt know where to map these,
> anyway...
> These types seem to be intimately related to the geodatabase. ??.
>
> Which connects with the Subtypes.  You are right, these are not mapped to
> EML.
> I am just learning about these, somehow these elements escaped me, or I
> deemed
> unmappable to EML.  It looks like attributes.  I tried to read about these
> on the
> ESRI pages, but it was unclear to me what these are.  In practical terms,
> we may
> be able to map these to the attributes, as they seem to describe feautures,
> anyhow,
> and may be "derived attributes" (but attributes nonetheless).  So I am a
> bit at a
> loss, here, not sure whether it is appropiate to map these to EML, but I
> think we
> will miss important info (flow direction, coastline, connectors, etc are
> good examples
> of useful feature descriptions.)
>
> What do you say?  do these map to GML?  what exactly are the subtype
> describing?
>
> Thanks for sending these issues!
>
> cheers,
> inigo
>
> For example
>
>>
>>
>>
>> *E.g. See lines 178 and 184 on the **EML** xml file for one example of
>> this
>> problem.*
>>
>>
>>
>>  3.   *Additional information missing in **EML***
>>
>> *Subtype information*
>>
>> *See lines 485 through 868 on the FGDC xml file.*
>>
>>
>>
>>   - *subtype* – Subtype Information.  Describes the subtypes that have
>> been
>>   defined for a feature class in a geodatabase.  For example, within a
>>   utility pole feature class there might be subtypes representing wood,
>>   concrete, and metal poles.
>>   - *stname* - Subtype Name.  The name of the subtype.
>>   - *stcode* - Subtype Code.  The code for the subtype.  Each object in a
>>   feature class or table has a numeric value, or code, in an attribute
>> that
>>   identifies the subtype to which it belongs.
>>   - *stfield* – Subtype Attribute.  An attribute for which a default value
>>   or domain has been defined for this subtype.
>>   - *stflddnm* - Subtype Attribute Name.  The name of the attribute.
>>   - *stflddv* - Subtype Default Value.  The default value for this
>>   attribute for all objects of this subtype.  The default value will be
>> placed
>>   in the attribute when a new object is added to the subtype.
>>   - *stflddd* - Attribute Defined Domain - The domain that has been
>> defined
>>   for this attribute subtype.  When editing, only values that fall within
>> the
>>   domain are permitted.  For example, each type of pole might have a
>> different
>>   domain defining the range that is valid for the pole's material.
>>   - *domname* - Domain Name.  The name of the domain.
>>   - *domdesc* - Domain Description.  A description of the domain.
>>   - *domtype *- Domain Type.  The type of domain (e.g. "Range" or "Coded
>>   Value").
>>   - *mrgtype* - Merge Rule.  The rule used to determine the value to be
>>   placed in the attribute if objects are merged (e.g. "Default value",
>> "Sum
>>   values", or "Weighted average").
>>   - *splttype* - Split Rule.  The rule used to determin value to be placed
>>   in the attribute if objects are split (e.g. "Default value",
>> "Duplicate", or
>>   "Geometry ratio").
>>   - *domowner* - Domain Owner.  The owner of the domain.
>>   - *domfldtp* - Attribute Type.  The data type of the attribute (e.g.
>>   "Small Integer", "Integer", "Single", "Double", "String", or "Date").
>>
>>
>>
>> *Entity *
>>
>> *See lines 871 through 880 on the FGDC xml file.*
>>
>>   - *detailed* – Detailed Description.  Description of the entities,
>>   attributes, attribute values, and related characteristics encoded in the
>>   dataset.
>>   - *enttyp* – Entity Type.  The definition and description of a set into
>>   which similar entity instances are classified.
>>   - *enttypt* – Entity Type Count.  The number of objects that the entity
>>   contains.  For example, the number of features contained by a feature
>>   class or the number of rows contained by a table.
>>
>>
>> *Geodetic Information*
>>
>> *See lines 263 through 268 on the FGDC xml file.*
>>
>>   - *horizdn - *Horizontal Datum Name.*  *
>>   - *ellips* *- *Ellipsoid Name
>>   - *semi-axis *- Semi-major axis
>>   - *denflat *- Denominator of flattening ratio
>>
>> * *
>>
>> *
>>
>> *
>>
>>
>>
>>
>>
>> Let me know if you have any questions.  Many thanks again for all of your
>> help.  We are very grateful for the assistance you have given us with this
>> project.
>>
>> Cheers,
>> Jessica
>>
>>
>>
>>
>
>
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