MEDIN Standards Workshop
Standards / XML / Validation /
Transformation / ESRI
Introduction
– XML
– Schema and Validation
• XSD Schema
• Schematron
– Transformation
• Stylesheets
– ESRI ArcGIS
– Search
XML
XML
•Extensible Markup Language (XML)
– A metamarkup language
– The basic unit is called an element
Element
<tag attribute="attribute value">element value</tag>
Attribute
Opening tag
– Apparently similar to HTML but…
Closing tag
Metamarkup?
•What does metamarkup mean?
– There is no predefined and fixed set of tags
for XML
– XML allows implementers to define their
own set of tags to meet their needs
Examples
• Office Open XML (ISO/IEC 29500)
• Geography Markup Language (ISO 19136)
Markup – ESRI ArcGIS 10 XML
<idCitation>
<resTitle>Title</resTitle>
<date>
<createDate>20110906</createDate>
</date>
</idCitation>
Markup – ISO 19139 XML
<gmd:citation>
<gmd:CI_Citation>
<gmd:title>
<gco:CharacterString>Title</gco:CharacterString>
</gmd:title>
<gmd:date>
<gmd:CI_Date>
<gmd:date>
<gco:Date>2011-09-06</gco:Date>
</gmd:date>
<gmd:dateType>
<gmd:CI_DateTypeCode
codeList="...#CI_DateTypeCode"
codeListValue="creation">creation</gmd:CI_DateTypeCode>
</gmd:dateType>
</gmd:CI_Date>
</gmd:date>
</gmd:CI_Citation>
</gmd:citation>
Well-Formed
•XML has strict rules, e.g.:
– There must be one, and only one root
element
– All elements must have an opening
and closing tag
– Element names are case sensitive:
• <citation/> is different from <Citation/>
– XML conforming to the rules is said to
be well-formed
Well-Formed
<idCitation>
<resTitle>Title</resTitle>
<date>
<createDate>20110906</createDate>
</date>
</idCitation>
<idCitation>
<resTitle>Title</ResTitle>
<date>
Two root elements
<createDate>20110906
</date>
</idCitation>
<idPurp>Summary</idPurp>
Opening and closing tags
are different
No closing tag
Structure
•The markup defines data structure:
– It signifies which elements are
associated
– It can define semantics:
<date>
<createDate>20110906</createDate>
</date>
– It says nothing about how to display
data (there are exceptions to this rule)
XML is machine readable
•And…
– Human readable… honestly
Schema and Validation
Schema
•Schemas document the elements that are
permitted in an XML application
– XML that conforms to a schema is said
to be schema-valid
– XML that does not conform to a
schema is said to be invalid
XML Schema Definition Language
<xs:complexType name="CI_Citation_Type">
...
<xs:complexContent>
<xs:extension base="gco:AbstractObject_Type">
<xs:sequence>
<xs:element name="title"
type="gco:CharacterString_PropertyType"/>
<xs:element name="alternateTitle"
type="gco:CharacterString_PropertyType"
minOccurs="0" maxOccurs="unbounded"/>
<xs:element name="date"
type="gmd:CI_Date_PropertyType"
maxOccurs="unbounded"/>
...
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
Markup – ISO 19139 XML
<gmd:citation>
<gmd:CI_Citation>
<gmd:title>
<gco:CharacterString>Title</gco:CharacterString>
</gmd:title>
<gmd:date>
<gmd:CI_Date>
<gmd:date>
<gco:Date>2011-09-06</gco:Date>
</gmd:date>
<gmd:dateType>
<gmd:CI_DateTypeCode
codeList="...#CI_DateTypeCode"
codeListValue="creation">creation</gmd:CI_DateTypeCode>
</gmd:dateType>
</gmd:CI_Date>
</gmd:date>
</gmd:CI_Citation>
</gmd:citation>
Schematron
•Schematron is:
– A schema language for XML
• Document Schema Definition Language
(DSDL)
– Written in XML
– It’s an ISO Standard – ISO 19757-3
Find out more at: http://www.schematron.com/
Why use Schematron?
•XSD schema is unable to test some
constraints:
– The ability to specify a choice of
attributes
– The ability to vary the content model
based on the value of an element or
attribute (this sort of constraint is
common in the ISO 19115 logical
model)
•Implementing profiles (e.g. MEDIN):
– With Schematron there’s no need to
edit the underlying standardised XSD
Validation Workflow
XSD Schema Validation
ISO 19139
Schema Validation
Valid?
YES
ISO 19139 Table
A.1 Constraints
Schematron
Valid?
Schematron Validation
YES
MEDIN Profile
Schematron
Valid?
NO
YES
END PASS
END FAIL
Validation Tools
Select profile
XSD Schema
Schematron
schemas
Transformation
XSLT
•Extensible Stylesheet Language
Transformations (XSLT)
– Specifies rules for transforming one
XML instance into another XML
instance
– The output XML instance will have a
different structure from the input XML
instance
ESRI XML to MEDIN XML
•MEDIN XML must be follow the ISO 19139 XML
encoding
– Users may wish to use other software to
create and manage metadata (e.g. ESRI
desktop GIS)
– ESRI software manages metadata using XML
– The XML does not following the ISO 19139
standard
– The XML can be transformed to ISO 19139
– MEDIN provides resources to support this
Stylesheet Tools
ESRI ArcGIS
Versions
•ArcGIS 9
– FGDC / ISO
•ArcGIS 10
– ESRI Core Metadata
– Both use XML encoding
– The encodings are slightly different
– Why the change at version 10?
ESRI ArcCatalog – Options
ESRI ArcCatalog
Transformation
e.g. Internal use
e.g. External / Publish to DAC
ArcGIS 9 Metadata
Transformation
ArcGIS 10 Metadata
MEDIN Metadata
Transform Options
•Use MEDIN stylesheets
– ArcGIS 9 version
– ArcGIS 10 version (or the Validate
button)
•Implementation
– Any XSL stylesheet processor
(version1.0), e.g:
• ArcGIS 9 or 10 ArcToolBox
• Metadata Maestro