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Technical information OGC WMS – WFS – CSW. OGC: Open Geospatial Consortium. http://www.opengeospatial.org/ « non-profit, international, voluntary consensus standards organization that is leading the development of standards for geospatial and location based services » WMS: Web Map Service
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Technical informationOGCWMS – WFS – CSW WP6 1st Coordination and progress meeting
OGC: Open Geospatial Consortium • http://www.opengeospatial.org/ « non-profit, international, voluntary consensus standards organization that is leading the development of standards for geospatial and location based services » • WMS: Web Map Service • WFS: Web Feature Service • Catalogue Service [CSW] WP6 1st Coordination and progress meeting
WMS / WFS / CSW … Are Web Services… • Are requested « over HTTP » (use of a URL http://.... Or a HTTP form) • The parameters in the request HTTP communicate with the Web Service to indicate: • Which operation is called • With wich parameter +> Very simple to use. • They response: • A XML file (description of the response) • Or an image (Web Map Service, operation getMap) WP6 1st Coordination and progress meeting
WMS: Web Map Service • http://www.opengeospatial.org/standards/wms « Provides a simple HTTP interface for requesting geo-registered map images from one or more distributed geospatial databases. » « A WMS request defines the geographic layer(s) and area of interest to be processed. » « The response to the request is one or more geo-registered map images (returned as JPEG, PNG, etc) that can be displayed in a browser application. » « The interface also supports the ability to specify whether the returned images should be transparent so that layers from multiple servers can be combined or not. » WP6 1st Coordination and progress meeting
WMS: getCapabilities • The first operation supported by a WMS is: getCapabilities. • Response is a XML file describing: +> The information about the server (title, abstract, access constraints,…) +> The coordinate system, area, scale, … +> The datasets (layers), with for each: * is queryable * the legend to use * the title, * … WMS: http://serviziogeologico.apat.it/cocoon/Onegeology/wms_en GetCapabilities: http://serviziogeologico.apat.it/cocoon/Onegeology/wms_en?service=wms&request=getCapabilities&version=1.1.1 WP6 1st Coordination and progress meeting
WMS: getMap • The second operation supported by a WMS is: getMap • The query contains: +> The name of the layer(s) called +> The area (bbox), and the coordinate system used +> The type of the image (png, gif, …) +> The size of the image http://serviziogeologico.apat.it/cocoon/Onegeology/wms_en?VERSION=1.1.1&REQUEST=GetMap&SERVICE=WMS&LAYERS=ITA_APATSGI_EN_500k_Lithology&SRS=EPSG:4326&BBOX=2.342014940440123,35.581577943782676,22.854835453260648,48.197949615272464&WIDTH=1143&HEIGHT=703&FORMAT=image/png&STYLES=Default&TRANSPARENT=TRUE The response is… the image WP6 1st Coordination and progress meeting
WMS: getMap with SLD • A SLD is a Style (Styled Layer Description) describing +> How to draw the Features http://appgeosciml.brgm.fr/GeoserverGeoSciML_boreholes/wms?SERVICE=WMS&request=GetMap&LAYERS=brgm:fra_nordpdc_bss_brgm&WIDTH=800&HEIGHT=500&VERSION=1.0.0&FORMAT=image/png&SRS=EPSG:27582&BBOX=544892.9,2555869.7,732402.0,2675770.0&STYLES=bss http://appgeosciml.brgm.fr/GeoserverGeoSciML_boreholes/wms?SERVICE=WMS&request=GetMap&LAYERS=brgm:fra_nordpdc_bss_brgm&WIDTH=800&HEIGHT=500&VERSION=1.0.0&FORMAT=image/png&SRS=EPSG:27582&BBOX=544892.9,2555869.7,732402.0,2675770.0&STYLES=bss_withdepth_greaterThan_200 WP6 1st Coordination and progress meeting
WMS: getMap with SLD • <?xml version="1.0" encoding="utf-8"?> • <StyledLayerDescriptor version="1.0.0" > • <NamedLayer><Name>bss</Name><UserStyle> • <FeatureTypeStyle> • <Rule> • <ogc:Filter> • <ogc:PropertyIsEqualTo> • <ogc:PropertyName>prof_debut</ogc:PropertyName> • <ogc:Literal>0</ogc:Literal> • </ogc:PropertyIsEqualTo> • </ogc:Filter> • <PointSymbolizer> • <Geometry><ogc:PropertyName>geom_l2e</ogc:PropertyName></Geometry> • <Graphic> • <Mark><WellKnownName>triangle</WellKnownName> • <Fill><CssParameter name="fill">#fffc00</CssParameter></Fill> • <Stroke> • <CssParameter name="stroke">#000000</CssParameter> • <CssParameter name="stroke-width">1</CssParameter> • </Stroke> • </Mark><Size>10</Size> • </Graphic> • </PointSymbolizer> • </Rule> • </FeatureTypeStyle> • </UserStyle> • </NamedLayer> • </StyledLayerDescriptor> WP6 1st Coordination and progress meeting
WMS: getMap with SLD • <?xml version="1.0" encoding="utf-8"?> • <StyledLayerDescriptor version="1.0.0" > • <NamedLayer><Name>bss</Name><UserStyle> • <FeatureTypeStyle> • <Rule> • <ogc:Filter> • <ogc:PropertyIsGreaterThan> • <ogc:PropertyName>prof_fin</ogc:PropertyName> • <ogc:Literal>200</ogc:Literal> • </ogc:PropertyIsGreaterThan> • </ogc:Filter> • <PointSymbolizer> • <Geometry><ogc:PropertyName>geom_l2e</ogc:PropertyName></Geometry> • <Graphic> • <Mark><WellKnownName>triangle</WellKnownName> • <Fill><CssParameter name="fill">#990000</CssParameter></Fill> • <Stroke> • <CssParameter name="stroke">#000000</CssParameter> • <CssParameter name="stroke-width">1</CssParameter> • </Stroke> • </Mark><Size>5</Size> • </Graphic> • </PointSymbolizer> • </Rule> • </FeatureTypeStyle> • </UserStyle> • </NamedLayer> • </StyledLayerDescriptor> WP6 1st Coordination and progress meeting
WMS: getFeatureInfo • The third (optional) operation supported by a WMS is: getFeatureInfo • The query contains: +> The name of the layer(s) called +> The area (bbox), and the coordinate system used +> The size of the image +> The point in the image http://serviziogeologico.apat.it/cocoon/Onegeology/wms_en?&VERSION=1.1.1&REQUEST=GetFeatureInfo&SERVICE=WMS&LAYERS=ITA_APATSGI_EN_500k_Lithology&SRS=EPSG:4326&BBOX=2.34201494,35.581577944,22.854835453,48.197949615&WIDTH=1143&HEIGHT=703&INFO_FORMAT=text/html&FORMAT=image/png&FEATURE_COUNT=100&QUERY_LAYERS=ITA_APATSGI_EN_500k_Lithology&STYLES=default&X=442&Y=190 The response is… the attributes WP6 1st Coordination and progress meeting
WFS: Web Feature Service • http://www.opengeospatial.org/standards/wfs • « Defines an interface specifying requests for retrieving geographic features across the Web using platform-independent calls. » • « Defines interfaces and operations for data accessand manipulation on a set of geographic features, including: • Get or Query features based on spatial and non-spatial constraints • Create a new feature instance • Get a description of the properties of features • Delete a feature instance • Update a feature instance • Lock a feature instance • « The specified feature encoding for input and output is the Geography Markup Language (GML) although other encodings may be used. » WP6 1st Coordination and progress meeting
WFS: getFeature • WFS are several operations. The main is « getFeature » • The query contains: +> The name of the layer(s) called +> The filter to select features: * Area (bbox) * or other operations http://192.168.6.47/GeoserverGeoSciML/wfs?service=WFS&request=GetFeature&maxFeatures=3&typeName=fra_nordpdc_50k_fgeol The response is an XML file displaying the features (GML) WP6 1st Coordination and progress meeting
Catalogue Service • http://www.opengeospatial.org/standards/cat « Supports the ability to publish and search collections of descriptive information (metadata) about geospatial data, services and related resources. » « Providers of resources use catalogues to register metadata that conform to the provider's choice of an information model; such models include descriptions of spatial references and thematic information. » [WP4] « Client applications can then search for geospatial data and services in very efficient ways.» [WP6] WP6 1st Coordination and progress meeting
CSW getRecords CSW is the language used to request the catalogue service. • GetRecords: An operation to request for a list of results, according to a constraint (filter) http://193.56.4.106/geonetwork/srv/en/csw?request=GetRecords&service=CSW&version=2.0.2&CONSTRAINTLANGUAGE=FILTER&resultType=results&maxRecords=3&constraint_language_version=1.1.0&Constraint=<Filter xmlns="http://www.opengis.net/ogc" xmlns:gml="http://www.opengis.net/gml"><Not><PropertyIsLike><PropertyName>type</PropertyName><Literal>dataset</Literal></PropertyIsLike></Not></Filter> Response in XML form. +> Used for the search engine WP6 1st Coordination and progress meeting
CSWgetRecordById CSW is the language used to request the catalogue service. • GetRecordById: An operation to request for a record in the metadata catalogue, according to its ID http://193.56.4.106/geonetwork/srv/en/csw?request=GetRecordById&service=CSW&version=2.0.2&id=2865feee55bcc2f2c55075885d09faaa38e20c4 Response in XML form. WP6 1st Coordination and progress meeting
Conclusion • Simple to use • Several softwares (open source or commercial) implementing these standards • But… • Multilingual issues? • Harmonization issues? (GeoSciML for WFS, format of the getFeatureInfo response) • WFS: performance issues? WP6 1st Coordination and progress meeting
OneGeology EuropeServices WP6 1st Coordination and progress meeting
Portal Mapping rules Geological Survey C Geological Survey B Geological Survey A Datasets WMS Harmonized Web Services web WFS Datasets 1GE W*S Harmonization: • Mapping rules (between national data model and 1G data specification) • which database, which attribute, to fill 1GE data spec • Translations (dictionaries) • for a given attribute for which a dictionary is defined, for each national database value, which common dictionary concept has to be used. WP6 1st Coordination and progress meeting
1GE SLDs Data Base Datasets 1GE D A T A M O D E L getMap Datasets getCapabilities ? ? INSPIRE WMS getFeatureInfo 1GE 1GE INSPIRE WFS getFeatures GeoSciML Dictionnaries Transformation Service (coordinates) getCapabilities Geological Survey WP6 1st Coordination and progress meeting