MEDIN Standards Workshop

Standards / XML / Validation / Transformation / ESRI

Introduction

– XML– Schema and Validation

• XSD Schema• Schematron

– Transformation• Stylesheets

– ESRI ArcGIS– Search

Page 2

XML

XML

•Extensible Markup Language (XML)– A metamarkup language– The basic unit is called an element

– Apparently similar to HTML but…

Page 4

<tag attribute="attribute value">element value</tag>

Element

AttributeOpening tag 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

Page 5

Examples• Office Open XML (ISO/IEC 29500)• Geography Markup Language (ISO 19136)

Markup – ESRI ArcGIS 10 XML

Page 6

<idCitation> <resTitle>Title</resTitle> <date> <createDate>20110906</createDate> </date></idCitation>

Markup – ISO 19139 XML

Page 7

<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

Page 8

Well-Formed

Page 9

<idCitation> <resTitle>Title</resTitle> <date> <createDate>20110906</createDate> </date></idCitation>

<idCitation> <resTitle>Title</ResTitle> <date> <createDate>20110906 </date></idCitation><idPurp>Summary</idPurp>

No closing tag

Opening and closing tagsare different

Two root elements

Structure

•The markup defines data structure:– It signifies which elements are

associated– It can define semantics:

– It says nothing about how to display data (there are exceptions to this rule)

Page 10

<date> <createDate>20110906</createDate></date>

XML is machine readable

•And…– Human readable… honestly

Page 11

Page 12

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

Page 14

XML Schema Definition Language

Page 15

<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

Page 16

<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/

Page 17

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

Page 18

Page 19

Validation Workflow

Page 21

ISO 19139 Schema Validation

Valid?ISO 19139 Table A.1 Constraints

Schematron

MEDIN Profile Schematron

Valid?

Valid?

END FAIL

END PASS

YES

YES

YES

NO

XSD Schema Validation

Schematron Validation

Validation Tools

Page 22

Select profile

XSD Schema

Schematronschemas

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

Page 24

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

Page 25

Stylesheet Tools

Page 26

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?

Page 28

ESRI ArcCatalog – Options

Page 29

ESRI ArcCatalog

Page 30

Transformation

Page 31

ArcGIS 9 Metadata

ArcGIS 10 Metadata

MEDIN MetadataTransformation

e.g. Internal use e.g. External / Publish to DAC

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

Page 32