XML Schema Languages as a Technical Fundamental of Formalised Description

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XML SCHEMA LANGUAGESAS A TECHNICAL FUNDAMENTAL OF

FORMALISED DESCRIPTION OF MAPS

OTAKAR CERBA

Geomatics Section

Department of Mathematics

Faculty of Applied Sciences

University of West Bohemia in Pilsen

Czech Republic

The Future of Maps and the Internet, November, 13-15, 2009 Via Del Mar, Valparaiso, Chile


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Introduction

Ing. et Mgr. Otakar Cerba Geomatics section on University of West Bohemia in Pilsen

since 1995 Member of Czech cartographic society Application of XML technologies (XML schema languages,

XSLT) and data modeling techniques to digital cartography Projects: VisualHealth, Humboldt, Plan4all, SDI-EDU


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Objectives

Formalized description of map XML & XML schema languages RELAX NG language & its possibilities Formalized description of map through RELAX NG

Future steps Conclusion

namespace dc = " http://purl.org/dc/elements/1.1/ " start = Atlas_element |MapSet_element | Map_element Atlas_element = element Atlas {MapSet_or_Atlas}MapSet_element = element MapSet {MapSet_or_Atlas} MapSet_or_Atlas =

MapSet_element* & ap_element* & Metadata_DCMI Map_element = element Map {Technique_element+ & Metadata_DCMI} # Group of metadata elements common to allroot elements Metadata_DCMI = element dc:title {text} & element dc:creator{text} & element dc:description {text}? Technique_element = element Technique {

attribute name "Choropleth"} &element SourceData {attribute uri {xsd:anyURI}& attribute geometry {text} & element Parameter {text}* } & element Border{attribute width {xsd:decimal}+ & attribute colour {text}+ & attribute structure{text}+ }* & element Inside { attribute fillColour {text} | attribute fillURI

{xsd:anyURI} } & element Classification { attribute name {"Constant" |"Qunatilies" | "Standard_deviation"}+ & attribute classesNumber {xsd:decimal}+}
http://purl.org/dc/elements/1.1/http://purl.org/dc/elements/1.1/


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Cartography vs. Information technologies

Cartography

Informationtechnologies

Informationtechnologies

Web environment

Services

Data sharing

Automatedprocessing

Cartography

Web environment

Services

Data sharing

Automatedprocessing

Cartography is an information transfer process that is centred about a spatialdatabase which can be considered, initself, a multifaceted model of geographicreality. Such a spatial database thenserves as the central core of an entire

sequence of cartographic processes,receiving various data inputs anddispensing various types of informationproducts. (Guptill & Starr 1984).


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Situation in cartography

Cartographer who wants toshare maps, communicate,

through Internet and use WPS

Platform

Standard

Format

Specification

Datamodel

Platform Standard

Format Specification

Datamodel

Platform

Standard

Format

Specification

Datamodel

Platform

Standard

Format

Specification

Datamodel

Platform

Standard

Format

Specification

Datamodel

Standard SpecificationData

model


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Way from the labyrinth

Exploitation of cartographic benefits of the Internet

Removing of problems related to datamodels, data formats, platforms,

specifications, standards...

IT IS IMPOSSIBLE!!!

To eliminate consequences of heterogeneities

HOW?

Detailed and standardizeddescription of data models of all levels

and data formats through exchangeformat based on a platform

independent language

XML


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XML? What is it?

Markup language or metalanguage

XML marks the meaning of particular parts of

documents, but does notspecify their design XML describes data and

their structure

XML is the base of semantic data

1. XML is a protocol for containing and managinginformation.

2. XML is a family of

technologies that can doeverything from formattingdocuments to filtering data.

3. XML is a philosophy for information handling thatseeks maximum usefulnessand flexibility for data byrefining it to its purest andmost structured form.


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XML? Why do we need it?

XML

Independence

Freedom

Simplicity

Clarity

Expansion

Relations

Self-description


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XML schema languages? Why?We have XML...

XML can have an effect of bigger chaos.

XML is not a concrete dataformat. It is a set of rules for

building markup languages. Everybody can create and

use own names of elementsand attributes

No interoperability

?Where is

the promised interoperability?

The freedom to define tag namesand attributes has to be constrained


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XML schema languages enable to...

...define and describe any subset of XML a formaldefinition of a new markup language or format (e.g.elements, attributes, entities, their limits and restrictions)

...be used as filters or firewalls protecting computers

against heterogeneities of XML formats and languages ...be processed by special software called validators being

able to control the structure of data file ...eliminate the heterogeneities related to different data

structures, formats, models etc. ...create and work with PSVI (Post-Schema ValidationInfoset)

...generate documentation materials of XML-based formats


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XML schema languages

DTD W3C XML Schema RELAX NG

RELAXXduceTREX

SchematronExamplotron

XML-DataXML-Data-Reduced

Document Content DescriptionSchema for Object-Oriented XML

Document Definition Markup Language

XML schema languages enable unification, but...


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Which format is the best?

XML schema language XML format

DTD SVG 1.0, SVG 1.1, SVG Mobile Profiles, GML 1.0, SLD 0.71, X3D 3.0

W3C XML Schema KML 2.2, GML 2.0-3.2.1, LandXML 1.0-1.2, DiaML, SLD 0.72-1.1.0, X3D 3.0

RELAX NG SVG Tiny 1.2

element Map {element Title {text}}


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Relax with RELAX NG

RELAX NG = RELAX + TREX + Xduce ISO standard (ISO/IEC FDIS 19757-2 Document Schema

Definition Language (DSDL) -- Part 2: Regular-grammar-based validation RELAX NG)

Two forms of syntax XML-based and compact Support of XML Namespaces Re-using data types defined in W3C XML schema Relationship to Schematron

Transformation to other XML schema languages (DTD,W3C XML Schema, both syntax form of RELAX NG)through software Trang


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RELAX NG patterns

Elements, attributes, comments Mandatory and optional elements and attributes Sequence (order) of parts of data forced, free Multiple occurrence of elements Choices of elements and attributes Context parts of data dependent on other values of data Data types (in-built, W3C XML Schema) Enumeration data type Condition of data values


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Advantages of XML-based description

Based on the schemes it will be possible to create softwareuniformly processing described data

Data can be controlled using validators XML schema languages bring more comfort to the editors

In the case of choice of semantically understandablenames the description of maps will easy to read for people

Anyone who has once learned to describe the map with aspecific subset of the XML language, will be able to carry

out his work quickly and efficiently in other similar cases Only a formalized description will link with other standards Software working with formalized description allows to

generate not only a map sheet and its features, but alsocompositional elements, GUI, metadata


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Example: Structure of maps

Map

Metadata(DCMI)

Atlas

MapSet

dc:title

dc:creator

dc:description

Root elements Top-down modeling process


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Example: Structure of maps

namespace dc = "http://purl.org/dc/elements/1.1/"

start = Atlas_element | MapSet_element | Map_element

Atlas_element = element Atlas {MapSet_or_Atlas}

MapSet_element = element MapSet {MapSet_or_Atlas}

MapSet_or_Atlas =MapSet_element* &Map_element* &Metadata_DCMI

Map_element = element Map {Metadata_DCMI}

# Group of metadata elements common to all root elementsMetadata_DCMI =

element dc:title {text},element dc:creator {text}+,

element dc:description {text}?


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Example: Cartographic technique

Cartographictechniquesmodeling

Syntactictypes of

cartographicmethod

Visualvariables

Decompositionof cartographicsymbols

Assignment of properties of symbols

Mid-levelmodeling process

Source data

AbsolutelyRelatively(parametrization)


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Example: Choropleth maps

Choroplethmaps

Areals Borders

Type of fill(colour, pattern)

Width, colour,structure

Factors influencingselection of concretevisual variables:

They must be suitable for

quantitative data

describable withSVG

Source data

AbsolutelyRelatively


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Process of map generating used in VisualHealthproject and Atlas of International Relationships

Geodata

Visualisation

rules

Thematic mappresented

in the browser

Descriptionof the map

Transformationprocessor

GML, JML...

XSLT 2.0

XML(RELAX NG)

Saxon(or internal p.) SVG, KML...


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ogr:OB01

ogr:dietaogr:kombiogr:pdaogr:inzulin

Combination of choropleth map and pie charts


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Future steps technical view

Application of contexts based on the concrete values of elements or attributes

Strict data types declaration changing the general datatype text to a specific data type taken from the W3C XML

Schema or regular expressions The implementation of inheritance rules, which allows

sharing properties among the nested elements Modularization of long and complicated scheme structure

of maps, groups of maps or atlases, cartographictechniques and data types


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Conclusion advantages to web cartography

Validation automatically checking syntax of a document Interoperability communication and exchange of

information not only in cartographic domains Accessibility of cartographic products elimination the

impossibility of use of applications


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Conclusion - relations

Formalizeddescription

of maps

ICA ResearchAgenda

Next generationof Web (2.0...)

XMLtechnologies

Web services Spatial datainfrastructure

Expertsystems


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Conclusion

Increase in abstraction and formalization higher level of automated processes in cartography

Formalized language to describe the map positive changes in quality of services

wider use of other types of services providing dataand allowing for processing

But...Cartographers action cannot be completely replaced with

automated processes the formal description of the mapcannot constitute a final solution for creating maps but onlyone of the tools to support creative activities of cartographers,and a system to help the communication


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XML Schema Languages as a Technical Fundamental of Formalised Description