Presentation on theme: "SCAR Feature Type Catalogue"— Presentation transcript:
1SCAR Feature Type Catalogue Henk Brolsma / Ursula Ryan – Australian Antarctic DivisionSteffen Vogt – University Freiburg - Germany
2Chronology Tokyo 2000 - XXVI SCAR Siena 2001 – Project Coordinators Hobart 2002 – Australia / GermanyShanghai 2002 – XXVII SCARAt the Tokyo meeting in 2000 it was agreed that one of WG-GGIs goals was:To develop a SCAR standard Spatial Data Model for use in SCAR and national GIS databases. The Project leader was Australia with collaborators UK, Germany and Chile.At the Sienna meeting in 2001, a draft was presented and accepted by the SCAR committee members for consideration. SCAR funding was sought for Steffen Vogt to travel to Australia to assist in the development and editing of the draft model.Steffen has been in Hobart for three weeks working on the development with Ursula and HenkThe name of the Catalogue will be the “Feature Type Catalogue” as this name is compliant with ISO standards.
3AIMS Project Scope of the model Review ISO standards Produce and distribute draftPublish as SCAR standardThe project aims were to:1. determine the scope of the model (content and application of the SDM) and incorporate map symbology into the data dictionary2.Review ISO TC211 and other relevant standards3.Produce and distribute a draft SDM for comment4.Publish as a SCAR standard
4Feature Type Catalogue Definition A feature catalogue is a catalogue containing definitions and descriptions of the feature types, feature attributes and feature associations occurring in one or more sets of geographic data, together with any feature operations that may be applied - ISO 19110DEFINITION – ISO – Feature Cataloguing MethodologyA feature catalogue is a catalogue containing definitions and descriptions of the feature types, feature attributes and feature associations occurring in one or more sets of geographic data, together with any feature operations that may be applied - ISO 19110In developing the Feature Type Catalogue, it became obvious that the Structure of the catalogue and Definitions of Features would be critical elements as they determine the ability to share data from various data sources. They also dictate how symbology maybe created.
5STANDARDS ISO Standards 19110 Feature cataloguing 19111 Spatial referencing by coordinates19112 Spatial referencing by geographic identifiers19113 Quality principles19114 Quality EvaluationISO standardsThere are approximately 35 ISO standards relating to metadata, data quality, spatial schemas, spatial referencing, web map server interfaces and registration of . The ISO standards that we have taken into consideration in developing the Feature Type catalogue are: Feature cataloguing19111 Spatial referencing by coordinate19112 Spatial referencing by geographic identifiers19113 Quality principles19114 Quality Evaluation
6Definitions Definitions Structure Symbology Definitions If data is to be shared then we must first agree on the definitions of features. If features have different definitions then it is like trying to compare apples and pears.Definitions must be derived from internationally accepted sources such as the GEMET and GCMD thesaurus.GEMET - A thesaurus developed by the European Commission.GEMET is the General Multilingual Environmental Thesaurus (GEMET) that has been created by merging different national and international thesauri. UNEP is also using this thesaurus. The thesaurus is multilingual and would be very useful for this group to use – languages used are American, English, Bulgarian, Danish, Finish, German, Netherlands, Norwegian, Sweden, Russian, French, Greek, Italian, Portuguese, Spain, Hungary, Slovakia, American.SCAR featuresAll features will be coded so that it would not be difficult to translate from western languages to eastern languages. Codes will not be structured in any way, they will be used purely as unique identifiers and will be assigned by the computer.StructureThe Feature Type catalogue is object oriented with a flat structure. This structure allows the information to more readily shared with other data sources.When considering scientific data such as vegetation and invertebrates we have to take into consideration how the data is described in the SCAR Biodiversity data base – GGI must describe the data in the same way as it is described in that database. For example we have used generic terms to describe the vegetation – vegetation type or plant species.Birds In the case of Birds – flying birds or penquins.Symbology It is important at this stage in the development of the FTC to ensure that we attach to the features the correct and necessary attribute information so that these can be used to develop the symbology for use in digital and hard copy maps. Provided the feature definition and its attributes are correct the FTC can be used to search for features and symbols assigned to them for depicting at various scales.Janet Thomson from BAS has done a great deal of work on symbology and the definitions of features. This work will be incorporated into the Feature Type Catalogue in the next stage of development.
7Quality ISO 19113 Quality principles ISO 19114 Quality evaluation Purpose describing qualityQuality AttributesQuality AttributesTo comply with ISO standards it is essential that attributes which describe the quality of the data in the Feature Type Catalogue be included in the data description.ISO standard on quality principles states:“Geographic datasets are increasingly being shared, interchanged and used for purposes other than their producers’ intended ones. Information about the quality of available geographic datasets is vital to the process of selecting a dataset in that the value of data is directly related to its quality.”“The purpose of describing the quality of geographic data is to facilitate the selection of the geographic dataset best suited to application needs or requirements. Complete descriptions of the quality of a dataset will encourage the sharing, interchange and use of appropriate geographic datasets..”19114“For the purpose of evaluating the quality of a dataset, clearly defined procedures must be used in a consistent manner. This enables data producers to express how well their product meets the criteria set forth in its product specification and data users to establish the extent to which a dataset meets their needs.”The quality evaluation procedure described in this International Standard (19114) when applied in accordance with ISO 19113, provides a consistent and standard manner to determine and report a dataset’s quality information”This International Standard also establishes a framework for evaluating and reporting data quality results either as part of data quality metadata only or also as a quality evaluation report”PurposeFrom ISO standards and the purpose of describing the data quality becomes quiet obvious – use of data, evaluating data, sharing data etc.,
8Component Model Organisations And People Data Repository Applications InterfaceApplicationsSearchSpeciesTaxonomyInterfaceDataRepositoryObservablesDictionarySearchOntologiesRegister(using keywords)This shows the actual “components” of a SCAR distributed data network.Existing example components of the SCAR data network include:Antarctic Digital Database, RiSCC Biodiversity Database, KGIS database, Antarctic Masterdirectory (the SCAR Metadata Catalogue), SCAR Composite Gazetteer, SCAR Map Catalogue, etc.A variety of applications rely on the interoperability of these components. A simple example would be retrieving penguin census data using a search based on the name of the penguin colony. This involves the gazetteer, a spatial database (such as ADD or KGIS) and the RiSCC Biodiversity Database. A more complex application is the Cybercartographic Project of Antarctica Project.A crucial component in the data network is the Feature Type Catalogue. Key thing is that the Feature Type Catalogue is itself a living service, used to classify data and access services, but also within applications to locate services.Definition Ontology:An ontology formally defines a common set of terms that are used to describe and represent a domain. Ontologies can be used by automated tools to power advanced services such as more accurate Web search, intelligent software agents and knowledge management.FeatureTypeCatalogueServicesCatalogueSymbologyMetadataCatalogueMapCatalogueKeywordsCatalogs
9Data Model: ServicesThis graph shows that SCAR Map Catalogue, the Antarctic Masterdirectory, the SCAR gazetteer can all be regarded as online sevices. The relationships from top down are basically specialisations. Note the two cases of multiple inheritance: Gazetteer and Feature Type Catalog.Ontology services support polyhierarchical browsing, an key feature to more intelligent applications.The Feature Type Catalogue is not just a vocabulary – because Feature Types have complex structures defined (attributes, operations and relationships), thus the Feature Type Catalogue can be used as catalaogue service and as an ontology service as well.
10Data Model : Feature Types ExampleFeatureThe SCAR Feature is derived from the ISO Feature. This ensures ISO compliance. Each feature has attributes, a pointer to metadata (incl. data quality), and one or more geometries. The geometry includes the spatial reference.Definitions:Geographic Features real world phenomena with a location relative to the earth about which data are collected, maintained, and disseminatedFeature instance a discrete phenomenon that is associated with its geographic and temporal coordinates (Scott’s hut)Feature type classes of feature instances with common properties (a hut)Feature TypeDefinitions
11Building (attribute:type=“Hut”, beds=3) Strong or Weak TypingIs a feature best described as:GeneralFeature (attribute:type=“Hut”)OrBuilding (attribute:type=“Hut”, beds=3)Hut (beds=3)3 Bed Hut“Granularity” depends on usage requirementsThe granularity is driven by user requirements and data management requirements.
12Feature Type Catalogue Code:unique - arbitrarily assigned - simple idenfication- facilitates documentation of changesDefinition:- should be applicable to Antarctic applicationsshould be commonly accepted - preferably already established in the respective communityExternal Definition Sources - GEMET (multilingual, UNEP) - other SCAR projects - IHO...Name:- uniqueFeature Attributes can by- mandatory, - conditional (mandatory if applicable)optional general Attributes include - geometry (incl. the spatial reference system)pointer to metadata (incl. data quality)pointer to SCAR Gazetteer
13+ Symbology Portrayal a function of Feature Type … + attributes E.g. Building (function=Hospital)Feature Type Catalogue used to classify entries in symbol librariesSymbol sets shared+Portrayal (symbology) is linked to the Feature Type Catalogue, but can be regarded as a catalogue service in its own right. With this approach symbol sets can be shared across the web (OGC uses Styled Layer Descriptor XML or GML->SVG stylesheets)
14Advantages ISO compliant Common and consistent semantics Features have common structureEasy to link to portrayal schemes (symbology)Easy to create GML schemaFeature Type Catalogue can be used as a classification vocabularyFits into the bigger picture of distributed data networks
15SCAR Spatial Data Model it’s a dynamic documentThe SCAR Feature Type Catalogue is a dynamic document and continually evolving. Comments should be directed to