linked geodata - wherecampdc 20110610

04/12/2023U.S. Environmental Protection Agency

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Linked GeoData#WhereCampDC 2011

David G. Smith PE PLSUSEPA Office of Environmental Information

202-566-0797SmithG.David@epa.gov

Twitter:@DruidSmith

Linked DataWhat’s It All About?

Speak the Language of the Web• Just as you surf web pages, linked data lets you surf

data.• SOAP was about making the web try to work like

applications; REST was about making applications work like the web.

• Linked Data is about making your DATA work like the web.

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Linked DataWhat’s The Big Fuss?

Business Case Galore• Address the non-hierarchical nature of organizations• Combine information sources on the fly• W3C standards for interoperability to freely move

data• US Data Warehouse market in 2010 was $10B

http://www.slideshare.net/bhylandwood/bernadette-hyland-semtech-2011-west-linked-data-cookbook

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Linked Data Cloud

http://richard.cyganiak.de/2007/10/lod/

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Linked Data Basics

Speak the Language of the Web• Use URIs as names for things• Use HTTP URIs so that people can look up those

names.• When someone looks up a URI, provide useful

information, using the standards (RDF*, SPARQL)• Include links to other URIs, so that they can discover

more things.

http://www.w3.org/DesignIssues/LinkedData.html

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Linked Data Basics

Tim Berners-Lee: 5-Star model for publishing data

http://www.w3.org/DesignIssues/LinkedData.html04/12/2023 U.S. Environmental Protection Agency 6

Linked Data Basics

RDF Structure:

• Triples, much as one might deal with in graphs and other structures, with arcs and nodes – similar to ERDs and Class Diagrams

• Special sauce: These elements can be identified with URIs – not only makes them unique, it is self-describing and dereferenceable for more information!

http://www.w3.org/TR/rdf-concepts/

http://www.w3.org/DesignIssues/LinkedData.html

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Linked Data Basics

RDF Structure:

http://en.wikipedia.org/wiki/Resource_Description_Framework

http://www.w3.org/DesignIssues/LinkedData.html

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Linked Data Basics

RDF Structure:Represent the data in a common format, e.g. • RDF/XML, • Notation-3 (N3), • Turtle (.ttl), • N-Triples, • RDFa, and • RDF/JSON

http://en.wikipedia.org/wiki/Resource_Description_Framework

http://www.w3.org/DesignIssues/LinkedData.html

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Linked Data Best Practices

• Machine readable format• HUMAN readable descriptions• Visibility for search engines• RDFa and microformats• voID descriptions - http://vocab.deri.ie/void

http://www.slideshare.net/bhylandwood/bernadette-hyland-semtech-2011-west-linked-data-cookbook

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Linked Data Basics

Okay, so how do I use it?Query it, just as you would run a SQL query, i.e. SPARQL“Find me the capital of all countries in Africa”

PREFIX abc: <nul://sparql/exampleOntology#> .SELECT ?capital ?countryWHERE { ?x abc:cityname ?capital ; abc:isCapitalOf ?y. ?y abc:countryname ?country ; abc:isInContinent abc:Africa.}

http://en.wikipedia.org/wiki/Resource_Description_Framework

http://www.w3.org/DesignIssues/LinkedData.html

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Linked Data and Geo

So is this linked data stuff all unicorns and rainbows?

http://en.wikipedia.org/wiki/File:The_Hunt_of_the_Unicorn_Tapestry_7.jpg

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Linked Data and Geo

Linked GeoData• Some decisions to be made, complexity-dependent

– http://www.w3.org/2003/01/geo/ <geo:lat_long>51.4,-0.02</geo:lat_long>

– GeoRSS– GML– WKT– WorldKit

http://www.w3.org/wiki/GeoRDF

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Linked Data and Geo

What’s Going On?• UK – Ordnance Survey

http://data.ordnancesurvey.co.uk/.html

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Linked Data and Geo

What’s Going On?• OSM - LinkedGeoData

http://linkedgeodata.org/About

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Linked Data and Geo

What’s Going On?• GeoNames

http://www.geonames.org/ontology/documentation.html

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Linked Data and Geo

What’s Going On?• OGC - GeoSPARQL

http://www.opengeospatial.org/projects/groups/geosparqlswg

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SELECT ?fWHERE { ?f my:hasPointGeometry ?fGeom .?fGeom ogc:asWKT ?fWKT .FILTER (ogcf:relate(?fWKT,“<http://www.opengis.net/def/crs/OGC/1.3/CRS84>Polygon ((-83.5 34.0, -83.5 34.3, -83.1 34.3,-83.1 34.0, -83.5 34.0))”^^ogc:WKTLiteral,ogc:within))}

Linked Data and Geo

What is EPA doing?• Facility Registry System• Soon:

– Toxic Release Inventory– Substance Registry

• Collaborating– CIO Committee DAS– SOCOP http://socop.org/– HHS, USGS– http://www.w3.org/2011/gld/charter

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Linked Data Cloud

Here’s where the Cloud is…Where Are You?

http://richard.cyganiak.de/2007/10/lod/

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Thanks/Questions

David G. Smith PE PLS• USEPA Office of Environmental Information• 202-566-0797• SmithG.David@epa.gov• Twitter:@DruidSmith

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Topic URLFRS Home Site http://www.epa.gov/enviro/html/fii/FRS Geodata Download http://www.epa.gov/enviro/geo_data.htmlMy Environment http://www.epa.gov/myenvironment/EPA Geospatial Program http://www.epa.gov/geospatial/index.htmlEPA Geodata Gateway https://geogateway.epa.gov/EPA Geo Metadata https://geogateway.epa.gov/EME/