[Auscope-geosciml] An issue withISODataQualityand UnitsOfMeasure schema [SEC=UNCLASSIFIED]

Simon Cox simon.cox at jrc.ec.europa.eu
Wed Oct 14 02:42:00 EDT 2009


Ollie - you are reading very grumpy about this. 
What do you propose instead? 
 
In this case there are indeed various 'anomalies' caused by the fact that
the development of the ISO UML for 19103, 19115, and 19107 in particular
were not synchronized with GML or indeed with the web in general. 
And there are other even more appropriate technologeis that have come along
subsequently, like SKOS.  
I'm afraid various people and groups were involved, bringing various
requirements and experience to the table, and it is quite a triumph of
cooperation that it is as aligned as well as it is. 
Future specs will have less anomalies because we understand the system as a
whole better now. 
 
I've tried to explain a way to understand it. 
If that is not good enough for you, then you are quite welcome to go off and
reinvent the whole thing so that it is consistent. 
Eric may 'have it', but I'm afraid that the real world includes compromises.

So you will just have to learn to live with it.  
 
Thats the last I'm going to say on the topic. 
 
Simon
 

--------------------------------------------------------
Simon Cox

European Commission, Joint Research Centre 
Institute for Environment and Sustainability 
Spatial Data Infrastructures Unit, TP 262 
Via E. Fermi, 2749, I-21027 Ispra (VA), Italy 
Tel: +39 0332 78 3652 
Fax: +39 0332 78 6325 
 <mailto:simon.cox at jrc.ec.europa.eu> mailto:simon.cox at jrc.ec.europa.eu 
 <http://ies.jrc.ec.europa.eu/simon-cox>
http://ies.jrc.ec.europa.eu/simon-cox 

SDI Unit:  <http://sdi.jrc.ec.europa.eu/> http://sdi.jrc.ec.europa.eu/ 
IES Institute:  <http://ies.jrc.ec.europa.eu/> http://ies.jrc.ec.europa.eu/ 
JRC:  <http://www.jrc.ec.europa.eu/> http://www.jrc.ec.europa.eu/

--------------------------------------------------------

 

  _____  

From: auscope-geosciml-bounces at lists.arcs.org.au
[mailto:auscope-geosciml-bounces at lists.arcs.org.au] On Behalf Of
Oliver.Raymond at ga.gov.au
Sent: Wednesday, 14 October 2009 00:37
To: auscope-geosciml at lists.arcs.org.au
Cc: John.Hockaday at ga.gov.au
Subject: Re: [Auscope-geosciml] An issue withISODataQualityand
UnitsOfMeasure schema [SEC=UNCLASSIFIED]



Eric has it.  Now we realise that ISO schemas do not necessarily reflect the
ISO UML.  But unless we construct instance docs as we model, or carry the
ISO documentation with us, we are unlikely to realise that our model which
uses ISO elements will not be delivered as we expect.  In the case of
UnitOfMeasure, the difference between UML and schema is not insignificant.

 

Data modelling teams like us construct models using UML, not xsd, and until
now (as Eric points out) we have expected the xsd to replicate the UML (eg;
GeoSciML UML goes into FullMoon, isomorphic GeoSciML xsd comes out the other
end).  I suppose now that we are going to use SKOS/RDF mappings for encoding
GSML vocabularies, the assumption of UML/XSD isomorphism no longer holds for
GeoSciML either.

 

Cheers,

Ollie

 

----------------------------------------------------------------------------
--------------------

Ollie Raymond
National Advice,  Maps and Standards Project

Geoscience Australia

 

Address: GPO Box 378, Canberra, ACT, 2601, Australia | ABN: 80 091 799 039

Ph: (02) 62499575 | Fax: (02) 62499992 | Email: Oliver.Raymond at ga.gov.au 

Web:
<http://www.ga.gov.au/minerals/research/national/nat_maps/nat_geol_maps.jsp>
http://www.ga.gov.au/minerals/research/national/nat_maps/nat_geol_maps.jsp
<http://www.ga.gov.au/geoscience/national> 

 
<http://maps.google.com/maps?f=q&hl=en&geocode=&q=canberra+australia&ie=UTF8
&ll=-35.344028,149.158362&spn=0.007684,0.016404&t=h&z=17&iwloc=addr&om=1>
Google Map 

 

-- This message was created with 100% recycled electrons --

 

 

-----Original Message-----
From: auscope-geosciml-bounces at lists.arcs.org.au
[mailto:auscope-geosciml-bounces at lists.arcs.org.au] On Behalf Of Simon Cox
Sent: Wednesday, 14 October 2009 2:03 AM
To: auscope-geosciml at lists.arcs.org.au
Cc: Hockaday John
Subject: Re: [Auscope-geosciml] An issue withISODataQualityand
UnitsOfMeasure schema [SEC=UNCLASSIFIED]

 

>90% of the time the assumption is correct. 

But in some places the UML is clumsier than an available implementation
(e.g. compare Measure with gml:MeasureType, GenericName with gml:CodeType,
CharacterString with xs:string) or there is another reason why the
implementation does not follow the encoding rule (e.g. most of the basic
geometry classes are implemented by something that is slightly different in
GML). In these cases the encoding rule is overridden by a mapping. 

 

It is mostly in basic datatypes where you wouldn't notice or care. 

I'm a little unclear why Ollie does in this case. 

 

--------------------------------------------------------
Simon Cox

European Commission, Joint Research Centre 
Institute for Environment and Sustainability 
Spatial Data Infrastructures Unit, TP 262 
Via E. Fermi, 2749, I-21027 Ispra (VA), Italy 
Tel: +39 0332 78 3652 
Fax: +39 0332 78 6325 
 <mailto:simon.cox at jrc.ec.europa.eu> mailto:simon.cox at jrc.ec.europa.eu 
 <http://ies.jrc.ec.europa.eu/simon-cox>
http://ies.jrc.ec.europa.eu/simon-cox 

SDI Unit:  <http://sdi.jrc.ec.europa.eu/> http://sdi.jrc.ec.europa.eu/ 
IES Institute:  <http://ies.jrc.ec.europa.eu/> http://ies.jrc.ec.europa.eu/ 
JRC:  <http://www.jrc.ec.europa.eu/> http://www.jrc.ec.europa.eu/

--------------------------------------------------------

 

 

  _____  

From: auscope-geosciml-bounces at lists.arcs.org.au
[mailto:auscope-geosciml-bounces at lists.arcs.org.au] On Behalf Of Boisvert,
Eric
Sent: Tuesday, 13 October 2009 13:27
To: auscope-geosciml at lists.arcs.org.au
Cc: John.Hockaday at ga.gov.au
Subject: Re: [Auscope-geosciml] An issue withISODataQualityand
UnitsOfMeasure schema [SEC=UNCLASSIFIED]

I can understand Ollie's comment because we have been working for some times
now with the assumption that the UML was the only representation of the
model, XSD was just a Fullmoon click away.  So our model is isomorphic (is
it ?) and as Ollie, I expected other UML of the ISO/OGC familly would also
be.  

 

Is your comment saying "those other UML are not ismorphic and it is sad" or
"UML models, including GeoSciML, are not required to be isomorphic"..  This
has an impact because the trend is to include other models (Metadata, SKOS,
O&M, Sampling) and we do this through UML.

 

Eric

 

  _____  

De : auscope-geosciml-bounces at lists.arcs.org.au
[mailto:auscope-geosciml-bounces at lists.arcs.org.au] De la part de Simon Cox
Envoyé : 13 octobre 2009 04:15
À : auscope-geosciml at lists.arcs.org.au
Cc : John.Hockaday at ga.gov.au
Objet : Re: [Auscope-geosciml] An issue with ISODataQualityand
UnitsOfMeasure schema [SEC=UNCLASSIFIED]

The UML model is a conceptual schema, not a graphical view of the XML
schema. 

The use of a regular encoding rule makes them generally isomorphic, but not
fully. 

You just have to trust the encoder, which uses mappings as well as rules. 

 

If you want a view of the schema, then use an XML tool, not UML. 

 

--------------------------------------------------------
Simon Cox

European Commission, Joint Research Centre 
Institute for Environment and Sustainability 
Spatial Data Infrastructures Unit, TP 262 
Via E. Fermi, 2749, I-21027 Ispra (VA), Italy 
Tel: +39 0332 78 3652 
Fax: +39 0332 78 6325 
 <mailto:simon.cox at jrc.ec.europa.eu> mailto:simon.cox at jrc.ec.europa.eu 
 <http://ies.jrc.ec.europa.eu/simon-cox>
http://ies.jrc.ec.europa.eu/simon-cox 

SDI Unit:  <http://sdi.jrc.ec.europa.eu/> http://sdi.jrc.ec.europa.eu/ 
IES Institute:  <http://ies.jrc.ec.europa.eu/> http://ies.jrc.ec.europa.eu/ 
JRC:  <http://www.jrc.ec.europa.eu/> http://www.jrc.ec.europa.eu/

--------------------------------------------------------

 

 

  _____  

From: auscope-geosciml-bounces at lists.arcs.org.au
[mailto:auscope-geosciml-bounces at lists.arcs.org.au] On Behalf Of
Oliver.Raymond at ga.gov.au
Sent: Monday, 12 October 2009 23:41
To: auscope-geosciml at lists.arcs.org.au
Cc: John.Hockaday at ga.gov.au
Subject: Re: [Auscope-geosciml] An issue with ISO DataQualityand
UnitsOfMeasure schema [SEC=UNCLASSIFIED]

Hmm, it just makes it difficult for us poor souls who are trying to use the
ISO UML to model our data when it doesn't accurately reflect what will be
delivered by the xml schema....

 

 

 

  _____  

From: auscope-geosciml-bounces at lists.arcs.org.au
[mailto:auscope-geosciml-bounces at lists.arcs.org.au] On Behalf Of Simon Cox
Sent: Monday, 12 October 2009 7:50 PM
To: auscope-geosciml at lists.arcs.org.au
Cc: Hockaday John
Subject: Re: [Auscope-geosciml] An issue with ISO DataQuality and
UnitsOfMeasure schema [SEC=UNCLASSIFIED]

Ollie - Its all OK. 

 

You have to distinguish between the abstract model and the implementation. 

 

Sometimes they are related by a rule (e.g. the 19136 Annex E, or 19139
encoding rule), but sometimes they are just related by a 'mapping',
particularly if there is a pre-existing implementation that captures the
semantics. 

Thats what has happened in this case. 

 

It is also explained in Annex D of ISO 19136 (GML) where the GML
implementations of classes from ISO 19103 are explained. 

 

Simon

 

--------------------------------------------------------
Simon Cox

European Commission, Joint Research Centre 
Institute for Environment and Sustainability 
Spatial Data Infrastructures Unit, TP 262 
Via E. Fermi, 2749, I-21027 Ispra (VA), Italy 
Tel: +39 0332 78 3652 
Fax: +39 0332 78 6325 
 <mailto:simon.cox at jrc.ec.europa.eu> mailto:simon.cox at jrc.ec.europa.eu 
 <http://ies.jrc.ec.europa.eu/simon-cox>
http://ies.jrc.ec.europa.eu/simon-cox 

SDI Unit:  <http://sdi.jrc.ec.europa.eu/> http://sdi.jrc.ec.europa.eu/ 
IES Institute:  <http://ies.jrc.ec.europa.eu/> http://ies.jrc.ec.europa.eu/ 
JRC:  <http://www.jrc.ec.europa.eu/> http://www.jrc.ec.europa.eu/

--------------------------------------------------------

 

 

  _____  

From: auscope-geosciml-bounces at lists.arcs.org.au
[mailto:auscope-geosciml-bounces at lists.arcs.org.au] On Behalf Of
Oliver.Raymond at ga.gov.au
Sent: Monday, 12 October 2009 08:53
To: auscope-geosciml at lists.arcs.org.au
Subject: [Auscope-geosciml] An issue with ISO DataQuality and UnitsOfMeasure
schema [SEC=UNCLASSIFIED]

Hi all,

 

I have discovered a quirk/bug in the ISO DataQuality UML model and schemas
that we should be aware of, but should not be a show-stopper for us using
ISO DataQuality.

 

According to the ISO19115 UML model (see diagram below),
gmd:DQ_QuantitativeAttributeAccuracy/result/DQ_QuantitativeResult/valueUnit
is of type gco:UnitOfMeasure (imported from ISO 19103).

 



 

 

However, contrary to the above UML diagram, the ISO19139 XML schema
implementation (gco/basicTypes.xsd) actually imports UnitOfMeasure from GML
(ISO 19136), not from ISO 19103.  As a result, the attributes of
DQ_QuantitativeResult/valueUnit that appear in the XML schema are quite
different to those shown in the ISO 19115 UML diagram.

 

Snippet from gml/units.xsd....

 

  <element name="unitOfMeasure" type="gml:UnitOfMeasureType">

    <annotation>

      <documentation>The element gml:unitOfMeasure is a property element to
refer to a unit of measure. This is an empty element which carries a
reference to a unit of measure definition.</documentation>

    </annotation>

  </element>

  <complexType name="UnitOfMeasureType">

    <sequence/>

    <attribute name="uom" type="gml:UomIdentifier" use="required"/>

  </complexType>

  <element name="UnitDefinition" type="gml:UnitDefinitionType"
substitutionGroup="gml:Definition">

    <annotation>

      <documentation>A gml:UnitDefinition is a general definition of a unit
of measure. This generic element is used only for units for which no
relationship with other units or units systems is known.

The content model of gml:UnitDefinition adds three additional properties to
gml:Definition, gml:quantityType, gml:quantityTypeReference and
gml:catalogSymbol.  

The gml:catalogSymbol property optionally gives the short symbol used for
this unit. This element is usually used when the relationship of this unit
to other units or units systems is unknown.</documentation>

    </annotation>

  </element>

  <complexType name="UnitDefinitionType">

    <complexContent>

      <extension base="gml:DefinitionType">

        <sequence>

          <element ref="gml:quantityType" minOccurs="0"/>

          <element ref="gml:quantityTypeReference" minOccurs="0"/>

          <element ref="gml:catalogSymbol" minOccurs="0"/>

        </sequence>

      </extension>

    </complexContent>

  </complexType>

 

 UML diagram of the GML UnitDefinition class from ISO 19136:

 



 

 

My colleague John Hockaday is contacting the lead author of ISO 19139 to
find out why the schema and the ISO 19115 UML don’t match.

 

Cheers,

Ollie

 

----------------------------------------------------------------------------
--------------------

Ollie Raymond
National Advice,  Maps and Standards Project

Geoscience Australia

 

Address: GPO Box 378, Canberra, ACT, 2601, Australia | ABN: 80 091 799 039

Ph: (02) 62499575 | Fax: (02) 62499992 | Email: Oliver.Raymond at ga.gov.au 

Web:
<http://www.ga.gov.au/minerals/research/national/nat_maps/nat_geol_maps.jsp>
http://www.ga.gov.au/minerals/research/national/nat_maps/nat_geol_maps.jsp
<http://www.ga.gov.au/geoscience/national> 

 
<http://maps.google.com/maps?f=q&hl=en&geocode=&q=canberra+australia&ie=UTF8
&ll=-35.344028,149.158362&spn=0.007684,0.016404&t=h&z=17&iwloc=addr&om=1>
Google Map 

 

-- This message was created with 100% recycled electrons --

 

 

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