TOP10NL GML prototype

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TOP10NL GML prototype

• 2nd GML Relay, 13-12-2002
• Marian de Vries

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1st GML Relay 12 June 20012 participants
IONIC Software
Laser-Scan
Maybe too early !
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Why this 2nd Relay

• 1,5 year later
• more companies have invested in GML
• .. but GML is still not mainstream
• data barrier problem not yet solved
• (GIS) users want transparent data exchange

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Overview

• TOP10Vector project
• GML why
• GML how
• TOP10NL GML prototype

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TOP10Vector project

• Started in 2000
• Project cooperation
• Topografische Dienst ( Dutch NMA)
• Center for Geo Information Wageningen
• ITC Enschede
• Geodesy dept. TU Delft
• User groups

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TOP10Vector project

• Dutch topographic data originally
• old goal map making
• lines, points and label-points (annotiation
  symbols), implicit polygons
• no unique ids
• no feature info, only classification code
  (TDN-code)

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TOP10Vector project

• User groups asked for
• more object-oriented data model
• also non-spatial attributes (names, road type, )
• metadata
• history / temporal queries
• easy aggregation (thematic, geometry)
• unique id --gt linking with other data

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TOP10Vector project

• Additional goal
• conformance to standards OpenGIS, ISO, CEN
• Why?
• mif, e00, dxf, SQLLoad files vendor specific
• NEN 1878 Dutch, not international

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Overview

• TOP10Vector project
• GML why
• GML how
• TOP10NL GML prototype

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GML Geography Markup Language

• Has XML as technical format
• content between begin and end tags
• supported by non-GIS tools
• XML eXtensible
• has XML Schema as data definition language

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GML XML
ltPolygon srsNamehttp//www.opengis.net/gml/srs/e
psg.xml2393gt ltouterBoundaryIsgt
ltLinearRinggt ltcoordinatesgt
3586549.54,6790984.34 3586598.23,6790924.09
3586649.23,6790952.23 3586549.54,6790984.34
lt/coordinatesgt lt/LinearRinggt
lt/outerBoundaryIsgt ltinnerBoundaryIsgt
lt/innerBoundaryIsgt lt/Polygongt
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Dutch NEN 1878 fixed position
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GML fits TOP10 renewal wishes

• Is open standard (of OpenGIS Consortium, in
  cooperation with ISO)
• Is based on object oriented data model
• features with spatial non-spatial properties,
  unique ids
• data oriented, not map oriented

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GML 2.1 geometry model
Point LineString LinearRing Polygon MultiPoint Mul
tiLineString MultiPolygon Box
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Basic GML element tree
FeatureCollection featureMember
Feature nonSpatialProperty
nonSpatialProperty
geometryProperty Geometry
(Polygon, LineString, Point etc.)
geometryProperty Geometry
(Polygon, LineString, Point etc.)
nonSpatialProperty
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TOP10NL GML data example
lttdnWegDeel fid"TOP10.402814"gt
lttdntop10_idgt2400001lt/tdntop10_idgt
lttdnbronRef xlinktype"simple"
xlinkhref"metadata.xmlTOP10.9000017"/gt
lttdnobject_begindatumgt2001-12-17T1324100200lt/
tdnobject_begindatumgt ...
lttdntoegankelijkheidgtOpenbaarlt/tdntoegankelijkhe
idgt lttdnstatusgtIn gebruiklt/tdnstatusgt
ltgmlpolygonPropertygt ltgmlPolygon
srsName"EPSG28992"gt ... lt/gmlPolygongt
lt/gmlpolygonPropertygt ltgmlgeometryPropertygt
ltgmlLineString srsName"EPSG28992"gt
ltgmlcoordinatesgt 106045.396,449000
105965.228,448967.705 105619.713,448827.507
lt/gmlcoordinatesgt lt/gmlLineStringgt
lt/gmlgeometryPropertygt lttdnwegtypegtAutosnel
weglt/tdnwegtypegt lttdnhoofdverkeersgebruikgtSne
lverkeerlt/tdnhoofdverkeersgebruikgt ...
lttdnwegnummergtA12lt/tdnwegnummergt
lttdnwegnummergtE25lt/tdnwegnummergt
lttdnwegnummergtE30lt/tdnwegnummergt lt/tdnWegDeelgt
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GML implementations

• First implementor
• Ordnance Survey Master Map
• Runners-up
• Germany (NorthRhine Westphalia)
• American Census Bureau (TIGER/Line)
• Dutch Topographic Service (TDN)
• Scandinavia, France, ...
• Both online (OGC WFS) and offline

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GML ! ready-to-use format

• you have to design your own data model
• organisation or domain specific, e.g.
• for topographic data
• for cadastral data
• for environmental data
• each in their own namespace ...

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GML spec. class repository
(abstract) types
gmlAbstractFeatureCollectionType gmlFeatureAssoc
iationType gmlAbstractFeatureType gmlGeometryPr
opertyType gmlAbstractGeometry
element names
gmlpolygonProperty gmllineStringProperty
... gmlPolygon gmlPoint ... gmlcoordinates gml
Box
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From conceptual data model
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to technical GML model
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to GML .xsd schema
lt!--
Type definition of
Top10ObjectType ( inherited and extended by
all
TOP10 feature types)
--gt
ltcomplexType name"Top10ObjectType"
abstract"true"gt ltcomplexContentgt
ltextension base"gmlAbstractFeatureType"gt
ltsequencegt ltelement
name"top10_id" type"integer"/gt
ltelement ref"tdnbronRef"/gt
ltgroup ref"tdnTemporeel"/gt
ltelement name"dimensie" type"tdndimensie"/gt
ltelement name"tdncode"
type"integer"/gt lt/sequencegt
lt/extensiongt lt/complexContentgt
lt/complexTypegt
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Reuse of classes in GML spec.
lt!--
Type definition of
Top10ObjectType ( inherited and extended by
all
TOP10 feature types)
--gt
ltcomplexType name"Top10ObjectType"
abstract"true"gt ltcomplexContentgt
ltextension base"gmlAbstractFeatureType"gt
ltsequencegt ltelement
name"top10_id" type"integer"/gt
ltelement ref"tdnbronRef"/gt
ltgroup ref"tdnTemporeel"/gt
ltelement name"dimensie" type"tdndimensie"/gt
ltelement name"tdncode"
type"integer"/gt lt/sequencegt
lt/extensiongt lt/complexContentgt
lt/complexTypegt
gmlAbstractFeatureCollectionType gmlFeatureAssoc
iationType gmlAbstractFeatureType gmlGeometryPr
opertyType gmlAbstractGeometry
gmlpolygonProperty gmllineStringProperty
... gmlPolygon gmlPoint ... gmlcoordinates gml
Box
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Overview

• TOP10Vector project
• GML why
• GML how
• TOP10NL GML prototype

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TOP10NL GML prototype

• 10 Feature types
• WegDeel, WaterDeel, SpoorbaanDeel, Terrein
  complete cover of surface
• Gebouw
• InrichtingsElement
• 4 Gebieden ( Admin. Areas) feature types
• 7 Feature collections

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TOP10NL GML prototype

• Some characteristics
• feature types with more than 1 geometry
• mixed geometries
• use of Xlink/XPointer
• cardinality (multiplicity) of properties
• ...

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Infrastructure types have 2 geometries
ltcomplexType name"InfrastructuurType"
abstract"true"gt ltcomplexContentgt
ltextension base"tdnTop10ObjectType"gt
ltsequencegt ltelement name"type"
type .../gt ltelement
name"toegankelijkheid" type /gt
ltelement name"status" type"tdnstatus"/gt
ltelement ref"gmlpolygonProperty"/gt
ltelement ref"gmlgeometryProperty"/gt
lt/sequencegt lt/extensiongt
lt/complexContentgt lt/complexTypegt
Road, Railway, Water inherit from this type
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Intersection polygon point, same id
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Metadata per object -gt XLink/XPointer
lttdnWaterDeel fid"TOP10.101221"gt
lttdntop10_idgt6100001lt/tdntop10_idgt
lttdnbronRef xlinkhref"metadata.xmlTOP10.900001
7"/gt
lttdnBron id"TOP10.9000017"gt
lttdnbron_idgt9000017lt/tdnbron_idgt
lttdnbrontypegtGeïnterpreteerde luchtfotolt/tdnbron
typegt lttdnbronbeschrijvinggtOrthogonale
luchtfoto, vlieghoogte ca 3800 meter schaal
118000lt/tdnbronbeschrijvinggt
lttdnbronactualiteitgt1998lt/tdnbronactualiteitgt
lttdnbronnauwkeurigheidgt5 meterlt/tdnbronnauwkeur
igheidgt lt/tdnBrongt
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More than 1 value -gt more than 1 element
lttdnWegDeel fid"TOP10.150044"gt
lttdntop10_idgt2105003lt/tdntop10_idgt
lttdnbronRef xlinktype"simple xlinkhref
.../gt lttdnontstaan_uitgt6100004lt/tdnontstaan_u
itgt lttdnontstaan_uitgt2100012lt/tdnontstaan_uit
gt lttdnontstaan_uitgt5100212lt/tdnontstaan_uitgt

history in data originated_from property
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Example 2 WegNummer (RoadNo.)
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Null value --gt no element
lttdnWegDeel fid"TOP10.101784"gt
lttdntop10_idgt2110084lt/tdntop10_idgt
lttdnbronRef xlinktype"simple" xlinkhref
.../gt lttdnontstaan_uitgtlt/tdnontstaan_uitgt
lttdnobject_begindatumgt2001-12-11T1138150200
lt/tdnobject_begindatumgt ...
Leave empty element out
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Processing GML

• Three strategies
• write data specific software (e.g. Ordnance
  Survey GML importers)
• offer core compliance / only support standard
  GML geometry names and data types
• try to write generic software -gt parse .xsd
  schema first

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And now the 2nd Relay

• Will they succeed ?
• Which strategy did they choose ?
• What dangers will they encounter ...

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lt/complexTypegt ltelement name"Gebouw"
type"tdnGebouwType" substitutionGroup"gml
_Feature"/gt ltcomplexType name"GebouwType"gt
ltcomplexContentgt ltextension
base"tdnTop10ObjectType"gt
ltsequencegt ltelement name"type"
type"tdntypeGebouw"/gt ltelement
name"functie" type"tdnfunctieGebouw"/gt
ltelement name"hoogteklasse"
type"tdnhoogteklasse"/gt ltelement
name"hoogte" type"tdnnumeriekOnb"/gt
ltelement name"status" type"tdnstatus"/gt
ltelement ref"gmlgeometryProperty"/gt
ltelement name"hoogteniveau"
type"integer" minOccurs"0"/gt
ltelement name"naam" type"string"
minOccurs"0"/gt lt/sequencegt
lt/extensiongt lt/complexContentgt
lt/complexTypegt lt!--

Declarations for InrichtingsElementen ( one of
the themes)