6 Spatial Data and XML

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6.1 Standards 6.2 XML

6.3 GML 6.4 XSLT 6.5 SVG

6.6 Summary

Spatial Databases and GIS – Karl Neumann, Sarah Tauscher– Ifis – TU Braunschweig 494

6 Spatial Data and XML

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• Collection of spatial data is particularly expensive

• Spatial data is durable, must be updated nevertheless

• Geoservices are increasingly offered by the internet

• Spatial data should be capable of being integrated and easily interchangeable

• Unified visualization of spatial data is desirable

• Preferably do not use individual formats but common standards

6 Spatial Data and XML

http://picture.yatego.com/

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• De facto standards emerge over time through frequent use

• De facto standards are standardized by institutions

• In the area of standards for spatial data the following institutions are important

– International Organization for Standardization (ISO) – Open Geospatial Consortium (OGC)

– Working Committee of the Surveying Authorities of the States of the Federal Republic of Germany

(Arbeitsgemeinschaft der Vermessungsverwaltungen der Länder der Bundesrepublik Deutschland (AdV))

6.1 Standards

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• International Organization for Standardization (ISO)

– International association of

standardization bodies from approx. 150 countries – Develops international standards in many technical

areas

– Serves the exchange of goods and services and the mutual cooperation

– In the area of spatial information 5 working groups (in ISO/TC 211)

6.1 Standards

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• National standardization bodies and ISO

6.1 Standards

http://www.geoinformation.net/

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• ISO/TC 211 geographic information/geomatics

– Approx. 60 members

– Edits the standard series ISO 19100

6.1 Standards

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• ISO 19107 Spatial Schema

6.1 Standards

(8)

• Geometry classes in the spatial schema

6.1 Standards

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• Open Geospatial Consortium (OGC)

– International consortium of approx. 440 members (industry, administration, research)

– Develops fundamentals for standardized access

methods for spatial

information

– Member of W3C

6.1 Standards

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– Products of the OGC are specifications

• Basic models, abstract specifications, implementation specifications

– Overview of abstract specifications

6.1 Standards

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– Particularly important: Simple Features

• Standard for modeling the geometry of spatial objects

• 0-, 1-, 2-dimensional, straight lines, no topology

6.1 Standards

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• SQL/MM spatial vs.

Simple Features geometry

6.1 Standards

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• Cooperation between ISO/TC 211 and OGC

6.1 Standards

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• Working Committee of the

Surveying Authorities of the States of the Federal Republic of Germany (AdV)

– Coordination of the German cadastral surveying – Development of recommendations for

• Authoritative topographic cartographic information system (amtliches topographisch-kartographisches

Informationssystem (ATKIS))

• Authoritative real estate cadastre information system (amtliches Liegenschafts-Kataster-Informationssystem (ALKIS))

6.1 Standards

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– Representation of the official German surveying in international institutions (see section 2.6 AAA-Project)

– Provide ISO/OGC-compliant components for spatial data infrastructure

– Example: AFIS-ALKIS-ATKIS specialized technical

schema with 226 object types, including

• Buildings

6.1 Standards

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• Object class: AX_Gebaeude with definition:

“A permanent building, whose documentation is required because of its importance as a property and which serves the purpose of the basic information of real estate cadastre”

• With 20 attributes, including:

• Function of building with approx. 200 values, including:

• 2000 (business/industry), 2056 (pharmacy), 2081 (restaurant), 3071 (police)

– Provide the technical schemas (and all object copies) in ISO/OGC-compliant formats

6.1 Standards

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• Example: a single building

<AX_Gebaeude gml:id="DEHHSERV00001FN1">

...

<gml:Polygon>

<gml:exterior>

<gml:Ring>

...

<gml:pos>3567807.047 5930017.550</gml:pos>

<gml:pos>3567810.850 5930024.755</gml:pos>

...

<gml:pos>3567807.047 5930017.550</gml:pos>

...

</gml:Ring>

</gml:exterior>

</gml:Polygon>

</position>

</AX_Gebaeude>

6.1 Standards

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• Extensible Markup Language

• Representation of hierarchically structured data in the format of text files

• Metalanguage for the description

and generation of markup languages

• "Standard for exchanging data on the web"

• "Special context-free grammar for defining specific context-free grammars"

6.2 XML

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• A (formal) grammar G = (N, , P, S) consists of

– A finite set N of nonterminal symbols

– A finite set  of terminal symbols, with   N = 

– A finite set P of production rules,

each rule of the form (  N)* N (  N)*  (  N)*

– A distinguished symbol S  N, the start symbol

6.2 Context-free Grammar

http://www.willamette.edu/~fruehr/

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• Example G = ({A,B,C,st},

{a,b,c,x},

{st  ABc, A  aAb, A  x,

B  BCc, bbB  ,

xCc  }, st)

(21)

• A context-free grammar (CFG) is a grammar G = (N, , P, S)

where all pP have the form

n  (  N)*

with nN

(22)

• A CFG generating n-tupels G_ntup = ({S, name, n-tuple, element, chars, letter, digit},

{[, ], 0, 1, …, 9. a, b, …, z, A, B. …, Z}, {S  [ name n-tuple ],

n-tuple  element n-tuple, n-tuple  , element  [ name chars ],

name  letter chars, chars  ,

chars  letter chars, chars  digit chars, letter  a, … z, A, …, Z, digit  0, …, 9 },

S)

(23)

• By applying some pP and reducing N and P

G_ntup defines another CFG G_addr=

({S, chars, letter, digit}

{[, ], 0, 1, …, 9. a, b, …, z, A, B. …, Z}, {S  [ address [ street letter chars ] [ houseNumber digit chars]

[ postalCode digit digit digit digit digit]

[city letter chars ] ] , chars  ,

chars  letter chars, chars  digit chars,

letter  a, … z, A, …, Z, digit  0, …, 9 }, S)

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• Some wL(G_ntup)

– [ n2 [ e1 28Xtw2a ] [ e2 why ] ]

– [ LX31a [ nb4d 46376233bstadwBGaC ]

[ jffd34gv FsL23rgJ ] [ ml22 Kernel ]

[ dd 35Tmndsl ] [ st st ] [ XTc noise7 ] ]

• Some wL(G_addr)

– [address [street Fischteichweg] [houseNumber 42A]

[postalCode 26603] [city Aurich] ]

– [address [street tc8] [houseNumber 35stg]

[postalCode 37240] [city groM2] ]

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• A (concrete) class of XML-based applications is also called document class

• An extension of such a class is called a document (or an application)

• The structure of

document classes can be specified by means of a

document type definition (DTD)

6.2 XML

http://www.swisseduc.ch/informatik/

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• Main components of the DTDs are

– Elements – Attributes – Entities

• Elements are the basic modules of XML documents

– Consist of a start and an end tag – May be empty

– May be nested (hierarchical structure of XML documents)

6.2 XML

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• Example: a DTD of a city

6.2 XML

classes city, name, inhabitants, area, polygon, point, x, y;

aggregations (city, name) (1), (city, inhabitants) (0..1), (city, area) (1),

(area, polygon) (1..n), (polygon, point) (4..n), (point, x) (1),

(point, y) (1);

<!ELEMENT city(name, inhabitants?, area)>

<!ELEMENT name (#PCDATA)>

<!ELEMENT inhabitants(#PCDATA)>

<!ELEMENT area(polygon+)>

<!ELEMENT polygon (point, point, point, point, point*)>

<!ELEMENT point(x, y)>

<!ELEMENT x (#PCDATA)>

<!ELEMENT y (#PCDATA)>

(28)

– A well-formed instance:

6.2 XML

<?xml version="1.0" standalone="yes"?>

<!DOCTYPE city SYSTEM "city.dtd">

<city><name>Braunschweig</name>

<area>

<point><x>10353</x><y>2484</y></point> ...

</polygon>

</area>

</city>

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– Another well-formed instance:

6.2 XML

<?xml version="1.0" standalone="yes"?>

<!DOCTYPE city SYSTEM "city.dtd">

<city><name>Ausschnitt</name>

<area>

<point><x>welchem</x><y>Text</y></point>

<point><x>Du</x><y>gleichst</y></point>

<point><x>dem</x><y>Geist</y></point>

...

<point><x>nicht</x><y>mir</y></point>

</polygon>

</area>

</city>

(30)

• Attributes specify additional properties of elements

– Example:

6.2 XML

[EE04]

<text font-family= "Arial" font-weight= "bold" font-size= "350"

stroke= "#FFFFFF" fill= "#FFFFFF" x= "-130.0" y="115.0"> U

</text>

(31)

• Entities

– Placeholder for content

– Will be declared once and can be used repeatedly – At each place of use the parser replaces reference by

appropriate value – Example:

6.2 XML

<!ENTITY baumgrün "#00ff00">

<!ENTITY grenzviolett "#9900ff">

<path id="SN4100_einzelsignaturNadelholz"

d="M 130 0 L -50 0 0 -180 50 0"

fill="none" stroke-miterlimit="20"

stroke-linejoin="miter"

stroke-width="12" stroke="&baumgrün;"/>

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• A central XML concept is integration of data and meta-data (XML documents include complete

self-descriptions)

• Therefore, removal of DTDs is obvious (for reuse)

• Large-scale projects may have several DTDs (possible name conflicts)

6.2 XML

http://www.xmlgrrl.com/publications/

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• For combining XML documents multiple concepts exist

– Namespaces – XPath

– XPointer – XLink

6.2 XML

http://www.jeckle.de/

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• Namespaces

– Are declared as attribute (of an element) and apply to all sub-trees of that element

– Include a Uniform Resource Identifier (URI) as address

6.2 XML

[EE04]

<AX_Bestandsdatenauszug

xmlns:gml="http://www.opengis.net/gml"...>

...<gml:featureMember>...

...</gml:featureMember>...

</AX_Bestandsdatenauszug>

(35)

• XML Path Language (XPath)

– Addressing within XML documents

– Basis of XSL Transformations (XSLT) and XPointer

– Navigation in XML documents (trees) with address paths

• Address paths

– Absolute (begin with '/' for root node) or – Relative (to the current context node)

– Contain axis information, node tests, predicates

6.2 XML

[EE04]

(36)

• XML Pointer Language (XPointer)

– Addressing parts of XML documents – Extension of XPath

– Simple references refer to XML elements which are identified by an ID

– Complex references with specifications of blocks (start-point, end-point, range)

6.2 XML

</g>

<use transform="translate(120515.9,152201.3) rotate(136)"

xlink:href="#SN3316SymbolKirche"/>

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• XML Linking Language (XLink)

– Syntax for defining links within XML documents

– XLinks are linking XML elements with other XML elements

– Declaration by xlink:href="URI"

– URI information may contain XPointer expressions

– There are simple (xlink: type = "simple") and extended (xlink: type = "extended") XLinks

– Extended XLinks are linking more than two sources

6.2 XML

http://graphics.cs.uni- sbxlink:href="URI".de/

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• Structure of XML documents can be defined by DTDs

• However, expressiveness of DTDs is restricted

– No specific data

types (only CDATA) – Only few structuring

options by sub-elements

– Integrity constraints hardly definable

<!ELEMENT city(name, inhabitants?, area)>

<!ELEMENT name (#PCDATA)>

<!ELEMENT inhabitants(#PCDATA)>

<!ELEMENT area(polygon+)>

<!ELEMENT polygon

(point, point, point, point, point*)>

<!ELEMENT point(x, y)>

<!ELEMENT x (#PCDATA)>

<!ELEMENT y (#PCDATA)>

6.2 XML

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• XML-Schema

– Language for modeling structured information – Describes by schema language

• Data types

• Documents

• Document Groups

– Alternative to DTDs

– Element contents can be typed and reused

– Allows limitations of value ranges and specifications of cardinalities

6.2 XML-Schema

</restriction>

</simpleType>

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• Numerous data types are provided, including

– xsd:string, xsd:boolean, xsd:decimal, xsd:float, xsd:time, xsd:date, xsd:integer (xsd: namespace of XML-Schema)

• Construction of data types with

– Base type with restrictions

• Length specifications, patterns, ranges, enumerations

• List types and union types

6.2 XML-Schema

<xsd:simpleType name="ObjektartName">

<xsd:restriction base="xsd:string">

<xsd:pattern value="A[XP]_[a-zA-Z0-9_]+"/>

</xsd:restriction>

</xsd:simpleType>

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• Complex element declarations are possible

6.2 XML-Schema

[EE04]

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• Example of a complex element declaration

6.2 XML-Schema

</choice>

</complexType>

</element>

</sequence>

</complexType>

</element>

</choice>

</complexType>

</element>

</sequence>

</complexType>

</element>

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• Example of an element instance

6.2 XML-Schema

...

<Bezeichnung>Schriftformat F K 28 blau</Bezeichnung>

<Schriftart>Arial</Schriftart>

<Schriftstil>Fett, Kursiv</Schriftstil>

</Schriftfarbe>

</SchriftStyle>

<Effekt>Grossbuchstaben</Effekt>

</SchriftSignatur>

</Signatur>

...

</Signaturen>

(44)

• Definition of keys and foreign keys

6.2 XML-Schema

[EE04]

(45)

• Geography Markup Language

• Markup Language generated by the use of XML (and XML-Schema); XML application

• To exchange spatial objects (in the OGC context: "features")

• Defined by the Open Geospatial Consortium with the ISO TC 211

• Defines numerous constructs for modelling own spatial applications, including

– Objects (features) and geometries

6.3 GML

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• The basic elements and data types are defined in 33 XML-Schema documents (base schemas)

• A concrete application has to be derived from the given schemas

6.3 GML

[SX08]

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• The central class is the abstract feature type

• “All specific feature types defined in application

schemas must be derived from AbstractFeatureType”

6.3 GML

</sequence>

</extension>

</complexContent>

</complexType>

(48)

• Among others the geometries of the “Simple Features” are provided

– Typically 2-dimensional geometries with straight lines – Including points, lines, polygons

6.3 GML

(49)

• Definition of the polygon type

6.3 GML

</complexType>

</element>

</complexType>

</element>

</sequence>

</extension>

</complexContent>

</complexType>

(50)

• Definition of an own feature type

6.3 GML

</sequence>

</extension>

</complexContent>

</complexType>

(51)

• AFIS ALKIS ATKIS schema of the AdV is a (very large) example of a GML-

compliant modeling of a spatial application

• Consists of a base schema (contains common base classes for spatial objects)

• And of technical schemas (containing all object classes needed for representing the information occurring in cadastral surveying)

• For ALKIS there exist more than 220 object types including numerous types of relationships

6.3 GML

http://www.adv-online.de/

(52)

• Here only a very small example is presented:

the schema of a single object class

"AX_Gebaeude" (simplified)

6.3 GML

<element name="gebaeudefunktion"

type="adv:AX_GebaeudefunktionType"/>

<element maxOccurs="unbounded" minOccurs="0"

name="weitereGebaeudefunktion"

type="adv:AX_Weitere_GebaeudefunktionType"/>

name="name" type="string"/>

<element maxOccurs="unbounded" minOccurs="0" name="nutzung"

type="adv:AX_Nutzung_GebaeudePropertyType"/>

(53)

6.3 GML

<element minOccurs="0" name="bauweise"

type="adv:AX_Bauweise_GebaeudeType"/>

<element minOccurs="0" name="anzahlDerOberirdischenGeschosse"

type="integer"/>

<element minOccurs="0" name="anzahlDerUnterirdischenGeschosse"

type="integer"/>

<element minOccurs="0" name="dachform"

type="adv:AX_DachformType"/>

<element minOccurs="0" name="zustand"

type="adv: AX_Zustand_GebaeudeType"/>

name="baujahr" type="integer"/>

<element minOccurs="0" name="lageZurErdoberflaeche"

type="adv:AX_LageZurErdoberflaeche_GebaeudeType"/>

(54)

<element minOccurs="0" name="dachgeschossausbau"

type="adv:AX_Dachgeschossausbau_GebaeudeType"/>

name="zeigtAuf" type="gml:ReferenceType">

</element>

name="gehoert" type="gml:ReferenceType">

</element>

</element>

name="haengtZusammenMit" type="gml:ReferenceType">

</element>

</sequence>

</extension>

</complexContent>

</complexType>

6.3 GML

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<AX_Gebaeude gml:id="DEHHSERV00001FN1">

...

<gml:Polygon>

<gml:exterior>

<gml:Ring>

<gml:pos>3567807.047 5930017.550</gml:pos>

<gml:pos>3567810.850 5930024.755</gml:pos>

...

<gml:pos>3567807.047 5930017.550</gml:pos>

</gml:Ring>

</gml:exterior>

</gml:Polygon>

</position>

</AX_Gebaeude>

– An instance of "AX_Gebaeude" (simplified)

6.3 GML

"position":

inherited of class

AG_ObjektType

(56)

• GML serves (also) for the exchange of spatial objects

• Therefor the Web Feature Service (WFS) was defined

– Web-based access to data "of a distributed GIS"

– Only vector data are exchanged

– Requests are sent as a HTTP request from a client to the WFS

6.3 GML

http://workshops.opengeo.org/

(57)

– WFS offers the following operations

• GetCapabilities

• GetFeature

• DescribeFeatureType

• Transaction

• LockFeature

• GetCapabilities

– Describes which WFS services are available

– Gives the names of the available feature types

6.3 GML

http://www.htw-dresden.de/

(58)

• DescribeFeatureType

– Describes the schema of a feature type

• GetFeature

– Delivers an instance of a feature

– Supports spatial and non-spatial selections

6.3 GML

<wfs:Query typeName="AX_Gebaeude">

<ogc:Filter>

<ogc:PropertyIsEqualTo>

<ogc:PropertyName>weitereGebaeudefunktion</ogc:PropertyName>

<ogc:Literal>1170</ogc:Literal>

</ogc:PropertyIsEqualTo>

</ogc:Filter>

</wfs:Query>

(59)

• Extensible Stylesheet Language for Transformation

• Programming language to transform XML documents

• Computational complete

• Based on tree structure of XML documents

• Used to define transformation rules

• Is a declarative and functional programming language

6.4 XSLT

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• XSLT programs (XSLT stylesheets) are XML documents themselves

• Stylesheets are read by XSLT processors; based on the stylesheets' rules the XSLT processors then transforms input documents into output documents

6.4 XSLT

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• A transformation consists of transformation rules (templates) with the following structure

– An XPath-based pattern

– Instructions for constructing the target tree

• Patterns select nodes of the source tree

• From these nodes the instructions generate parts of the target tree

• Frame of a transformation (XSLT stylesheet):

6.4 XSLT

<?xml version="1.0" encoding="ISO-8859-1"?>

<xsl:stylesheet xmlns:xsl=http://www.w3.org/1999/XSL/Transform version="1.0">

<xsl:output method="xml" />

<!– rules -->

</xsl:stylesheet>

(62)

• Main construct is the template

– If several transformation rules are applicable, the most specific one is

applied

– Within a template

numerous instructions may occur

6.4 XSLT

http://data2type.de/xml/

<xsl:template match="...">

...instructions...

</ xsl: template>

(63)

• <xsl:apply-templates select = ... mode = ...>

... parameters may occur...

</xsl:apply-templates>

– Explicit call of templates

– In the select attribute specification of an XPath expression

– With it selection of the nodes to be processed

– If no select element is present, all direct child nodes are processed

– With the mode parameters further node selection can be performed

6.4 XSLT

(64)

• <xsl:value-of select = .../>

– Generates a string at the current position in the output tree

– String can be the value of a node or of a defined variable

– Select attribute selects node, variable, or parameter whose value is to be used

6.4 XSLT

(65)

• <xsl:for-each select = ...>

...instructions...

</xsl:for-each>

– Iteration instructions within a template definition

– All instructions within this statement are applied to all specified nodes

– Select attribute selects nodes

• <xsl:text>

– Generates static text in the result tree

6.4 XSLT

(66)

• <xsl:choose>

– Frame for sequence of queries – <xsl:when test = ...>

...instructions... </xsl:when>

– Queries are finished with <xsl:otherwise>

– Those query is selected whose condition as first yields true

• <xsl:if test = ...> ...instructions... </xsl:if>

– Conditional execution of instructions – Test attribute contains condition

6.4 XSLT

(67)

• Example for the use of XSLT

– Transformation of XML-compliant extracts of the digital landscape model (DLM25)

into TK25-like graphics (see section 3.2) – Here: derivation rule for local roads

(are drawn as white lines with a narrow purple boundary)

– Template scans data for local roads and generates drawing commands

6.4 XSLT Example

(68)

• A (fairly short) road in the given landscape dataset

6.4 XSLT Example

<gml:name>Badstrasse</gml:name>

<gml:centerLineOf>

<gml:coord>

<gml:X>4437952.980</gml:X>

<gml:Y>5331812.550</gml:Y>

</gml:coord>

<gml:coord>

<gml:X>4437960.070</gml:X>

<gml:Y>5331818.450</gml:Y>

</gml:coord>

<gml:coord>

<gml:X>4437967.200</gml:X>

<gml:Y>5331825.410</gml:Y>

</gml:coord>

</gml:centerLineOf>

(69)

6.4 XSLT Example

<Zustand>in Betrieb</Zustand>

<AnzahlDerFahrstreifen

Bedeutung="tatsaechliche Anzahl"> 2 </AnzahlDerFahrstreifen>

<Funktion>Strassenverkehr</Funktion>

Anliegerverkehr

</VerkehrsbedeutungInneroertlich>

<BreiteDerFahrbahn>Keine Zuweisung </BreiteDerFahrbahn>

<Widmung>Gemeindestrasse</Widmung>

Attribut trifft nicht zu </InternationaleBedeutung>

Attribut trifft nicht zu

</VerkehrsbedeutungUeberuertlich>

</Attribute>

</Strasse>

</AtkisMember>

(70)

• Search for local roads

6.4 XSLT Example

<xsl:template

match="/dlm:AtkisModell/dlm:AtkisMember/dlm:Strasse">

<xsl:if test="contains(dlm:Attribute/dlm:Widmung,’Gemeindestrasse’) or contains(dlm:Attribute/dlm:Widmung,’Sonstiges’)">

<xsl:call-template name="DrawPath">

<xsl:with-param name="styleclass"

select="linieNebenstrasseNahverkehrVordergrund">

</xsl:call-template>

</xsl:if>

</xsl:template> <AtkisMember>

<gml:name>Badstrasse</gml:name>

<gml:centerLineOf>

<gml:coord>

<gml:X>4437952.980</gml:X>

<gml:Y>5331812.550</gml:Y>

</gml:coord>

(71)

• Generating line signatures

6.4 XSLT Example

<xsl:template name="DrawPath">

<xsl:param name="styleclass"/>

<svg:path>

<xsl:attribute name="class"><xsl:value-of select="$styleclass"/></xsl:attribute>

<xsl:attribute name="d">

<xsl:for-each select="gml:centerLineOf/gml:coord">

<xsl:choose>

<xsl:when test="position() = 1">

<xsl:text>M </xsl:text><xsl:call-template name="getX"/>

<xsl:text> </xsl:text><xsl:call-template name="getY"/>

<xsl:text> L </xsl:text>

</xsl:when>

<xsl:otherwise>

<xsl:call-template name="getX"/>

<xsl:text> </xsl:text><xsl:call-template name="getY"/>

<xsl:if test="position() != last()"><xsl:text> </xsl:text></xsl:if>

</xsl:otherwise>

</xsl:choose>

</xsl:for-each>

</xsl:attribute>

</svg:path>

</xsl:template>

(72)

• Templates "getX" and "getY" read x and y

coordinates, transform the coordinates into map coordinates, and write it to the current position in the output tree

• Style class

“linieNebenstrasseNahverkehrVordergrund”:

• Line which is generated in the example (SVG statement):

6.4 XSLT Example

.linieNebenstrasseNahverkehrVordergrund

{ fill: none; stroke-width: 8.5px; stroke: snow; stroke-linejoin: round}

<path class="linieNebenstrasseNahverkehrVordergrund"

d="M 8245.97 -2142.98 L 8253.65 -2146.15 8259.83 -2151.12"/>

(73)

• Scalable Vector Graphics (SVG)

• XML-based language for

describing two-dimensional, freely scalable vector graphics

• Standard of the W3C

• Beside static graphics also interactions, animation, and filter applications are provided

• SVG files are relatively small and are editable with any text editor

6.5 SVG

(74)

• SVG documents are structured like XML documents

– Prolog with XML declaration and document type declaration

– Root element, including

• Declaration of namespaces and

• Definition area (also for non-SVG code)

– Attributes "width" and "height" specify the width and the height of the entire graphic

– Optional attribute "viewBox" defines reference frame, specified are its left lower point and its width

6.5 SVG

(75)

– Example, declares a frame for a real estate map in the context of an A3 landscape format and a scale of

1:1000

6.5 SVG

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"

"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">

viewBox= "99269.744 150779.44 42000.0 29700.0"

xmlns:xlink= "http://www.w3.org/1999/xlink">

<defs>

.SN2028LinieFlurstueck{fill: none; stroke-width: 35; stroke-linecap: butt;

stroke-linejoin: miter; stroke: #000000;}

...

</style>

...

</defs>

...

</svg>

(76)

• Several SVG elements and attributes, including

– Line between 2 points (line)

– Line connecting several points (polyline) – Rectangle (rect)

– Circle – Ellipse – Polygon – Path

– Text

6.5 SVG

<rect x="5" y="5"

width="50" height="25"

style="stroke: blue; fill: none;">

</svg>