6 Spatial Data and XML - TU Braunschweig · 2017-12-05 · 6.1 Standards 6.2 XML 6.3 GML 6.4 SVG 6.5 Summary Spatial Databases and GIS – Karl Neumann, Sarah Tauscher– Ifis –

6.1 Standards

6.2 XML

6.3 GML

6.4 SVG

6.5 Summary

Spatial Databases and GIS – Karl Neumann, Sarah Tauscher– Ifis – TU Braunschweig 490

6 Spatial Data and XML

• Collection of spatial data is particularly expensive

• 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://www.lgmv.de/

• 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

• International Organization for

Standardization (ISO)

– International association of

standardization bodies from approx. 160 countries

– Founded in 1947

– Develops 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

• National standardization bodies and ISO


6.1 Standards

http://www.geoinformation.net/

• ISO/TC 211 geographic information/geomatics

– Approx. 65 members

– Edits the standard series ISO 19100


6.1 Standards


• ISO 19107 Spatial Schema


6.1 Standards


• Geometry classes in the spatial schema


6.1 Standards


• Open Geospatial Consortium (OGC)

– International consortium of approx. 510 members

(industry, administration, research), founded 1994

– Develops fundamentals for standardized access

methods

for spatial

information

– Member

of W3C

(since 2007)


6.1 Standards


– Products of the OGC are specifications

• Basic models, abstract specifications, implementation specifications

– Overview of abstract specifications


6.1 Standards



– Particularly important: Simple Features

• Standard for modeling the geometry of spatial objects

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


6.1 Standards

• SQL/MM spatial

vs.

Simple Features

geometry


6.1 Standards

• 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

– Representation of the official German surveying in

international institutions

(see chapter 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

• 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

• Example: a single building

<AX_Gebaeude gml:id="DEHHSERV00001FN1"> ... <position> <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> <gebaeudefunktion>2000</gebaeudefunktion> <weitereGebaeudefunktion>1170</weitereGebaeudefunktion> <bauweise>2100</bauweise> <anzahlDerOberirdischenGeschosse>1</anzahlDerOberirdischenGeschosse> <anzahlDerUnterirdischenGeschosse>1</anzahlDerUnterirdischenGeschosse> <dachform>3100</dachform> </AX_Gebaeude>


6.1 Standards

• 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

• 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

Phrase structure

Turing machine

Context-sensitive

Linear-bounded automata

Context-free

Push-down automata

Regular Finite-state automata

• Example

G = ({A,B,C,st},

{a,b,c,x},

{st ABc,

A aAb,

A x,

B BCc,

bbB ,

xCc },

st)



• A context-free grammar (CFG)

is a grammar G = (N, , P, S)

where all pP have the form

n ( N)*

with nN



• A CFG generating n-tupels Gntup =

({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)



• By applying some pP and reducing N and P Gntup defines another CFG Gaddr = ({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)



• Some wL(Gntup)

– [ n2 [ e1 28Xtw2a ] [ e2 why ] ]

– [ LX31a [ nb4d 46376233bstadwBGaC ]

[ jffd34gv FsL23rgJ ] [ ml22 Kernel ]

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

• Some wL(Gaddr)

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

[postalCode 26603] [city Aurich] ]

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

[postalCode 37240] [city groM2] ]



• Document class: a concrete class of XML-based

applications

• Document: extension of a document class

• The structure of

document classes

can be specified by

means of a

document type

definition (DTD)


6.2 XML

http://image.slidesharecdn.com/

• 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

• 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)>

– A well-formed instance:


6.2 XML

<?xml version="1.0" standalone="yes"?> <!DOCTYPE city SYSTEM "city.dtd"> <city><name>Braunschweig</name> <inhabitants>251000</inhabitants> <area> <polygon> <point><x>10323</x><y>2294</y></point> <point><x>10708</x><y>2429</y></point> <point><x>11148</x><y>2594</y></point> ... <point><x>10353</x><y>2484</y></point> </polygon> </area> </city>

– Another well-formed instance:


6.2 XML

<?xml version="1.0" standalone="yes"?> <!DOCTYPE city SYSTEM "city.dtd"> <city><name>Ausschnitt</name> <inhabitants>aus</inhabitants> <area> <polygon> <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>

• 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>

• 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;"/>

• To model non-hierachical structures and for

modularization of XML documents multiple

concepts exist

– Namespaces

– XPath

– XPointer


6.2 XML

• 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:pos>3540437.686 5804332.854</gml:pos> … </gml:featureMember> … </AX_Bestandsdatenauszug>

• XML Path Language (XPath)

– Addressing within XML documents (trees)

– Basis of XPointer

• Paths

– Absolute (begin with '/' for root node) or

relative (to the current context node)

– Contain axis information, node tests, predicates


6.2 XML

[EE04]

• XML Pointer Language (XPointer)

– Addressing parts of XML documents

– Extension of XPath

– Simple references refer to XML elements which are

identified by an ID


6.2 XML

<g id="SN3316SymbolKirche"> <path fill="none" stroke= "#000000" ... d="M0.0 -500.0 L 0.0 500.0"/> <path fill="none" stroke= "#000000" ... d="M-275.0 -200.0 L 275.0 -200.0"/> </g> … <use transform="translate(120515.9,152201.3) rotate(136)" xlink:href="#SN3316SymbolKirche"/>

• 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

• 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

<simpleType name="PrioType"> <restriction base="positiveInteger"> <minInclusive value="100"/> <maxInclusive value="999"/> </restriction> </simpleType>

• 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>

AX_Bestandsdatenauszug

• Complex element declarations are possible


6.2 XML-Schema

[EE04]

• Example of a complex element declaration


6.2 XML-Schema

<element name="Signaturen"> <complexType> <sequence> <element name="Signatur" minOccurs="1" maxOccurs="unbounded"> <complexType> <choice> <element name="FlaechenSignatur" type="loc:SigFlaeche"/> <element name="LinienSignatur" type="loc:SigLinie"/> <element name="SymbolSignatur" type="loc:SigSymbol"/> <element name="SchriftSignatur" type="loc:SigSchrift"/> </choice> <attribute name="Nr" type="loc:SigNrType" use="required"/> <attribute name="Typ" type="loc:SigTypType" use="required"/> <attribute name="Darstellungsprioritaet" type="loc:PrioType"use="required"/> <unique name="uniqueSigNr"><selector xpath="."/><field xpath="@Nr"/></unique> </complexType> </element> </sequence> </complexType> </element>

<element name="Signaturen"> <complexType> <sequence> <element name="Signatur" minOccurs="1" maxOccurs="unbounded"> <complexType> <choice> <element name="FlaechenSignatur" type="loc:SigFlaeche"/> <element name="LinienSignatur" type="loc:SigLinie"/> <element name="SymbolSignatur" type="loc:SigSymbol"/> <element name="SchriftSignatur" type="loc:SigSchrift"/> </choice> <attribute name="Nr" type="loc:SigNrType" use="required"/> <attribute name="Typ" type="loc:SigTypType" use="required"/> <attribute name="Darstellungsprioritaet" type="loc:PrioType"use="required"/> <unique name="uniqueSigNr"><selector xpath="."/> <field xpath="@Nr"/></unique> </complexType> </element> </sequence> </complexType> </element>

• Example of an element instance


6.2 XML-Schema

<Signaturen> ... <Signatur Nr="4286" Typ="Schrift" Darstellungsprioritaet="380"> <SchriftSignatur> <Bezeichnung>Schriftformat F K 28 blau</Bezeichnung> <SchriftStyle> <Schriftart>Arial</Schriftart> <Schriftstil>Fett, Kursiv</Schriftstil> <Schriftgrad>28 pt</Schriftgrad> <Schriftfarbe><Farbgrundton>Blau</Farbgrundton> <Cyan>100</Cyan> <Magenta>0</Magenta> <Yellow>0</Yellow><Black>20</Black> </Schriftfarbe> </SchriftStyle> <Effekt>Grossbuchstaben</Effekt> </SchriftSignatur> </Signatur> ... </Signaturen>

• Definition of keys and foreign keys


6.2 XML-Schema

[EE04]

• Geography Markup Language, generated by the

use of XML (and XML-Schema); XML application

• Version 3.2 identical with ISO 19136

• To exchange spatial objects

(in the OGC context: "features")

• Defined by OGC and ISO TC 211

• Defines numerous constructs for

modelling own spatial applications, including

– Objects (features) and geometries


6.3 GML

• 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]

• The central class is the abstract feature type

• “All specific feature types defined in application

schemas must be derived from AbstractFeatureType”


6.3 GML

<complexType name="AbstractFeatureType" abstract="true"> <complexContent> <extension base="gml:AbstractGMLType"> <sequence> <element ref="gml:boundedBy" minOccurs="0"/> <element ref="gml:location" minOccurs="0"/>  </sequence> <attribute name="fid" type="string"></attribute> </extension> </complexContent> </complexType>

• Among others the geometries of the "Simple

Features" are provided

– Typically 2-dimensional geometries with straight lines

– Including points, lines, polygons


6.3 GML

• Definition of the polygon type


6.3 GML

<complexType name="PolygonType"> <complexContent> <extension base="gml:AbstractGeometryType"> <sequence> <element name="outerBoundaryIs"> <complexType> <sequence><element ref="gml:LinearRing"/></sequence> </complexType> </element> <element name="innerBoundaryIs" minOccurs="0" maxOccurs="unbounded"> <complexType> <sequence><element ref="gml:LinearRing"/></sequence> </complexType> </element> </sequence> </extension> </complexContent> </complexType>

• Definition of an own feature type


6.3 GML

<complexType name="lakeType"> <complexContent> <extension base="gml:AbstractFeatureType"> <sequence> <element ref="gml:extentOf"/> <element name="lakeName" type="string"/> <element name="maxDepth" type="integer"/> <element name="area" type="decimal"/> </sequence> </extension> </complexContent> </complexType>

– Own feature type "lakeType" in the context of

GML types


6.3 GML

• 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/

• Here only a very small example is presented:

the schema of a single object class

"AX_Gebaeude" (simplified)


6.3 GML

<element name="AX_Gebaeude"/> <complexType name="AX_GebaeudeType"> <complexContent> <extension base="adv:AG_ObjektType"> <sequence> <element name="gebaeudefunktion" type="adv:AX_GebaeudefunktionType"/> <element maxOccurs="unbounded" minOccurs="0" name="weitereGebaeudefunktion" type="adv:AX_Weitere_GebaeudefunktionType"/> <element maxOccurs="unbounded" minOccurs="0" name="name" type="string"/> <element maxOccurs="unbounded" minOccurs="0" name="nutzung" type="adv:AX_Nutzung_GebaeudePropertyType"/>


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="hochhaus" type="boolean"/> <element minOccurs="0" name="objekthoehe" type="gml:LengthType"/> <element minOccurs="0" name="dachform" type="adv:AX_DachformType"/> <element minOccurs="0" name="zustand" type="adv: AX_Zustand_GebaeudeType"/> <element minOccurs="0" name="geschossflaeche" type="gml:AreaType"/> <element minOccurs="0" name="grundflaeche" type="gml:AreaType"/> <element minOccurs="0" name="umbauterRaum" type="gml:VolumeType"/> <element maxOccurs="unbounded" minOccurs="0" name="baujahr" type="integer"/> <element minOccurs="0" name="lageZurErdoberflaeche" type="adv:AX_LageZurErdoberflaeche_GebaeudeType"/>

<element minOccurs="0" name="dachart" type="string"/> <element minOccurs="0" name="dachgeschossausbau" type="adv:AX_Dachgeschossausbau_GebaeudeType"/> <element minOccurs="0" name="gebaeudekennzeichen" type="string"/> <element maxOccurs="unbounded" minOccurs="0" name="zeigtAuf" type="gml:ReferenceType"> </element> <element maxOccurs="unbounded" minOccurs="0" name="gehoert" type="gml:ReferenceType"> </element> <element minOccurs="0" name="gehoertZu“ type="gml:ReferenceType"> </element> <element maxOccurs="unbounded" minOccurs="0" name="haengtZusammenMit" type="gml:ReferenceType"> </element> </sequence> </extension> </complexContent> </complexType>


6.3 GML

<AX_Gebaeude gml:id="DEHHSERV00001FN1"> ... <position> <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> <gebaeudefunktion>2000</gebaeudefunktion> <weitereGebaeudefunktion>1170</weitereGebaeudefunktion> <bauweise>2100</bauweise> <anzahlDerOberirdischenGeschosse>1</anzahlDerOberirdischenGeschosse> <dachform>3100</dachform> </AX_Gebaeude>

– An instance of "AX_Gebaeude" (simplified)


6.3 GML

"position": inherited of class AG_ObjektType

• 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/

– 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/

• 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>

• 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


6.4 SVG

• 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, its width and height


6.4 SVG

– Example, declares a frame for a real estate map in the

context of an A3 landscape format and a scale of

1:1000


6.4 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"> <svg width= "42.0cm" height= "29.7cm viewBox= "99269.744 150779.44 42000.0 29700.0" xmlns:xlink= "http://www.w3.org/1999/xlink"> <defs> <style type="text/css"> .SN2028LinieFlurstueck{fill: none; stroke-width: 35; stroke-linecap: butt; stroke-linejoin: miter; stroke: #000000;} ... </style> ... </defs> ... </svg>

• Several SVG elements and attributes, including

– Line between 2 points (line)

– Line connecting several points (polyline)

– Rectangle (rect)

– Circle

– Ellipse

– Polygon

– Path

– Text


6.4 SVG

<svg width="70" height="40"> <rect x="5" y="5" width="50" height="25" style="stroke: blue; fill: none;"> </svg>

• Circle example (with instruction for grouping and

transformation)


6.4 SVG

<g style="fill-opacity:0.3; stroke:black; stroke-width:0.1cm;"> <circle cx="6cm" cy="2cm" r="100" style="fill:maroon;" transform="translate(0,50)"/> <circle cx="6cm" cy="2cm" r="100" style="fill:deepskyblue;" transform="translate(70,150)"/> <circle cx="6cm" cy="2cm" r="100" style="fill: limegreen;" transform="translate(-70,150)"/> </g>

• Path instruction for complex shapes, lines and areas

– Element’s attributes include the attribute "d" for specifying the points of the path

– Attribute "d" contains further commands for the interpretation of the points

– E.g. a point may be the begin or the end of a curve or of a line


6.4 SVG

<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;"/>

• Commands of the path instruction


6.4 SVG

command description example

M (MoveTo) specifies the starting point of a path M20 50

Z (ClosePath) generates a closed shape Z

L (LineTo) draws a line from the current point to the specified point

L50 100

H (Horizontal LineTo)

draws a horizontal line from the current point

H75

V (Vertical LineTo) draws a vertical line from the current point V40

C (CurveTo) draws a Bézier curve from the current point

C30 0 50 20 60 15

Q (Quadratic Bézier CurveTo)

draws a quadratic Bézier curve from the current point

Q40 0 60 20

A (Elliptical Arc) draws an elliptic arc from the current point A25 25 -30 0 1 50 -25

<path fill="none" stroke-width="3" stroke="green" d="M 20 20 l 0 -13 M 16 20 q 0 -10 -5 -10 M 12 20 q 0 -6 -4 -6 M 24 20 q 0 -10 5 -10 M 28 20 q 0 -6 4 -6" id="Pflanzensymbol"/>

• Path example (with quadratic Bezier curve)


6.4 SVG

• Path example (with grouping command and filled

areas)


6.4 SVG

<g id="SN3338SymbolApotheke">  <path d="M -250.0 250.0 L -250.0 -250.0 250.0 -250.0 250.0 250.0 Z“ fill= "#FFFFFF"/> <path d="M -200.0 145.0 L -118.0 88.0 -94.0 97.0 -94.0 72.0 -148.0 72.0 -148.0 -27.0 -94.0 -27.0 -94.0 -152.0 33.0 -200.0 161.0 -134.0 161.0 80.0 200.0 115.0 132.0 200.0 62.0 150.0 62.0 72.0 0.0 72.0 0.0 150.0 -73.0 200.0 Z“ fill= "#FF0000"/> <path d="M 0.0 -27.0 L 0.0 -119.0 62.0 -95.0 62.0 -27.0 Z" fill= "#FFFFFF"/> </g>

• Text instruction for text placement – Beside being a graphic

element, in SVG text is also available as a text element

– Several attributes, including “x” and “y” for positioning

– Texts can be translated and turned

– Orientation, alignment, font stretch may be specified among others


6.4 SVG

[SX08]

• Grouping instruction "g" to group elements

– Attributes of grouped elements can be specified

altogether, e.g. style attributes

– Groups can be named


6.4 SVG

<g id="SN3338SymbolApotheke"> <path d="M -250.0 250.0 L -250.0 ... Z" fill= "#FFFFFF"/> <path d="M -200.0 145.0 L -118.0 ... Z" fill= "#FF0000"/> <path d="M 0.0 -27.0 L 0.0 ... Z" fill= "#FFFFFF"/></g>

<g style="fill-opacity:0.3; stroke:black; stroke-width:0.1cm;"> <circle cx="6cm" cy="2cm" r="100" style="fill:maroon;" transform="translate(0,50)"/> <circle cx="6cm" cy="2cm" r="100" style="fill:deepskyblue;" transform="translate(70,150)"/> <circle cx="6cm" cy="2cm" r="100" style="fill:limegreen;" transform="translate(-70,150)"/></g>

– Also different elements may be grouped

• With the "use" element an

instance of a named element

(e.g. of a group) is created


6.4 SVG

<g id="SN3309SymbolParkhausParkdeck"> <path d="M-250.0 310.0 L -250.0 -190.0 0.0 -310.0 250.0 -190.0 250.0 310.0 Z" fill= "#00FFFF"/> <text font-family= "Arial" font-weight= "bold" font-size= "420" stroke= "#FFFFFF" fill= "#FFFFFF" x= "-130.0" y="150.0"> P </text> </g>

<use transform="translate(135463.0,173871.7)" xlink:href="#SN3309SymbolParkhausParkdeck"/>

• SVG can be combined with the

language

Cascading Style Sheets (CSS)

• CSS is a declarative

"style sheet language" for

structured documents

– Known essentially from the html environment

– A non XML based language for specifying format

instructions for document browsers


6.4 CSS

• A CSS style sheet consists of rules with the following structure

– Selector {property: value; ... property: value;}

– Selector specifies an element; values are assigned to the elements properties

– Selection criteria are properties of the elements (type, class, id, attribute values)

– Selection criteria can be combined

– Usually a simple selection with element names and user defined style classes is sufficient


6.4 CSS

htt

p:/

/lea

rnw

ebco

de.

com

/

– Example for selecting with element name

– Examples for user defined style classes

".name" shorthand for "*[class ~= name]"


6.4 CSS

.SN2505LinieGebaeude {fill: none; stroke-width: 18; stroke-linecap: butt; stroke-linejoin: miter; stroke: #000000;}

.SN1309FlaecheGebaeude {fill: #FF7F7F;}

text {font-family:verdana,sans-serif; font-size:40px; font-weight:bold;}


6.4 CSS

<path class="SN1309FlaecheGebaeude" d="M 109255.8 170060.4 109825.8 170177.9 109867.8 170186.6 109777.9 170628.6 110164.4 170713.6 110179.5 170683.1 111105.2 170903.4 110966.5 171523.6 110750.0 172482.6 109803.6 172264.3 110023.8 171309.5 109642.7 171223.0 109627.7 171289.0 109048.0 171164.0 109255.8 170060.4" /> . . . <path class="SN2505LinieGebaeude" d="M 109255.8 170060.4 109825.8 170177.9 109867.8 170186.6 109777.9 170628.6 110164.4 170713.6 110179.5 170683.1 111105.2 170903.4 110966.5 171523.6 110750.0 172482.6 109803.6 172264.3 110023.8 171309.5 109642.7 171223.0 109627.7 171289.0 109048.0 171164.0 109255.8 170060.4" />

• Overall the structure of a typical SVG document representing a map is as follows – Prolog with XML declaration and

document type definition

– Root element with • Declaration of name spaces

• Domain with Style classes

Named elements

• Elements for the actual drawing of the map with usage of user defined style classes and user defined elements

• Style classes and named elements represent the converted signatures of the respective map series


6.4 SVG

• Example (drastically shortened)


6.4 SVG Example

<?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"> <svg width= "42.0cm" height= "29.7cm" viewBox= "99269.744 150779.44 42000.0 29700.0" xmlns:xlink= "http://www.w3.org/1999/xlink"> <defs> <style type="text/css"> .SN1301FlaecheWohnenallgemein {fill: #999999;} .SN1309FlaecheGemeinwesenallgemein {fill: #FF7F7F;} .SN1409FlaecheAckerland {fill: #FFF7BF;} .SN2028LinieFlurstueck {fill: none; stroke-width: 35; stroke-linecap: butt; stroke-linejoin: miter; stroke: #000000;} ... </style>


6.4 SVG Example

<g id="SN3020SymbolGrenzpunktmitAbmarkungMarke"> <circle cx="0" cy="0" r="75" fill= "#FFFFFF" stroke-width= "18" stroke-linecap= "round" stroke-linejoin= "round" stroke= "#000000"/> </g>

<g id="SN3309SymbolParkhausParkdeck"> <path d="M-250.0 310.0 L -250.0 -190.0 0.0 -310.0 250.0 -190.0 250.0 310.0 Z" fill= "#00FFFF"/> <text font-family= "Arial" font-weight= "bold" font-size= "420" stroke= "#FFFFFF" fill= "#FFFFFF" x= "-130.0" y="150.0">P</text> </g>

<g id="SN3316SymbolKirche"> <path fill="none" stroke= "#000000" stroke-width= "70" stroke-linecap= "butt" d="M0.0 -500.0 L 0.0 500.0"/> <path fill="none" stroke= "#000000" stroke-width= "70" stroke-linecap= "butt" d="M-275.0 -200.0 L 275.0 -200.0"/> </g> ... </defs>

<g id="SN3020SymbolGrenzpunktmitAbmarkungMarke"> <circle cx="0" cy="0" r="75" fill= "#FFFFFF" stroke-width= "18" stroke-linecap= "round" stroke-linejoin= "round" stroke= "#000000"/> </g> <g id="SN3309SymbolParkhausParkdeck"> <path d="M-250.0 310.0 L -250.0 -190.0 0.0 -310.0 250.0 -190.0 250.0 310.0 Z" fill= "#00FFFF"/> <text font-family= "Arial" font-weight= "bold" font-size= "420" stroke= "#FFFFFF" fill= "#FFFFFF" x= "-130.0" y="150.0">P</text> </g> <g id="SN3316SymbolKirche"> <path fill="none" stroke= "#000000" stroke-width= "70" stroke-linecap= "butt" d="M0.0 -500.0 L 0.0 500.0"/> <path fill="none" stroke= "#000000" stroke-width= "70" stroke-linecap= "butt" d="M-275.0 -200.0 L 275.0 -200.0"/> </g> ... </defs>


6.4 SVG Example

<path class="SN1409FlaecheAckerland" d="M 163075.2 162043.4 193983.3 169300.5 196449.4 173480.0 201844.9 171788.3 200268.2 167276.0 196772.8 167241.7 193983.3 169300.5 193983.3 169300.5 163075.2 162043.4 180931.8 156813.0 198895.6 151572.3 205497.2 173730.9 190894.4 178027.0 169761.8 184244.2 161165.2 186773.1 154540.8 164531.3 163075.2 162043.4 "/> <path class="SN1301FlaecheWohnenallgemein" d="M 123960.0 147432.9 123875.2 147163.4 122999.8 147406.8 122680.8 146334.3 122686.9 146332.5 122616.2 146075.2 122926.8 145975.6 123002.2 146237.2 123310.1 146144.1 123237.3 145886.1 123471.4 145816.4 123542.1 146074.0 124228.2 145866.6 124631.9 147223.8 123960.0 147432.9 "/> <path class="SN1301FlaecheWohnenallgemein" d="M 111499.7 163673.7 111580.0 163524.5 111707.0 163590.7 111631.4 163745.8 111905.0 163895.8 111655.2 164349.4 111873.9 164464.9 111710.9 164754.3 111500.5 164630.4 111191.9 165190.8 110611.5 166280.3 109119.7 165473.0 109718.5 164381.2 110533.8 164829.2 111254.6 163539.4 111499.7 163673.7 "/>


6.4 SVG Example

<text class="SN4070SchriftSchriftformatN7380" x="101771.7" y="152661.6" transform="rotate(298, 101771.7, 152661.6)" style="text-anchor:middle"> 7</text> <path class="SN2028LinieFlurstueck" d="M 97500.0 134345.8 95762.3 131470.5 92887.4 126769.8 90013.4 121943.5 89040.0 120309.0 88213.4 119028.2 87314.6 117817.5 86282.6 116686.2 85167.5 115675.6 83887.6 114900.7 82581.0 114250.4 81131.0 113720.8 79689.9 113374.2 78183.7 113099.9 65450.8 111336.0 61192.8 110781.8 61420.6 109817.6 61513.5 109503.0 78351.9 111810.4 80055.0 112168.3 81678.6 112597.7 83280.9 113148.8 84486.0 113778.0 86267.9 114767.4 88137.0 116437.9 90324.1 120113.6 97702.1 132411.4 98275.1 133309.0 98637.4 133876.7 102813.9 140923.9 102996.0 141231.1 103646.0 142327.2 103810.2 142604.2 104510.2 143777.2 106326.4 146820.5 106914.1 147108.1 105217.3 147925.1 105352.9 147327.1 105247.1 147169.2 105188.5 146773.1 103512.5 144002.9 103400.2 144083.4 102172.1 142076.9 97500.0 134345.8"/> <text class="SN4111SchriftSchriftformatK10700" x="89451.7" y="78291.6"> 44/1</text>


6.4 SVG Example

<use transform="translate(44745.6,213153.9)" xlink:href="#SN3020SymbolGrenzpunktmitAbmarkungMarke"/> <use transform="translate(42021.4,192419.5)" xlink:href="#SN3020SymbolGrenzpunktmitAbmarkungMarke"/> ... </svg>

• Standards

– International Organization for Standardization (ISO)

– Open Geospatial Consortium (OGC)

– Working Committee of the Surveying Authorities of

the States of the Federal Republic of Germany (AdV)


6.5 Summary

• XML

– Standard for exchanging data on the web

– Elements, attributes, entities

– Name spaces, XPath, XPointer

– XML Schema

– Data types, elements

• GML

– Abstract feature type

– Definition of an own feature type

– AFIS ALKIS ATKIS schema of the AdV

– Web Feature Service


6.5 Summary

• SVG

– Rectangle

– Circle

– Path

– Text

– Grouping

– CSS

– Example "SVG map"


6.5 Summary


6.5 Summary

GIS

objects

thematic geometry

vector

collect

manage analyse

display

SVG

GML

XML