Documentation¶
This documentation assumes some knowledge of SPARQL (see http://www.linkeddatatools.com/semantic-web-basics for a basic primer).
Appropriate ontologies have been used to ensure the metadata stored in the triplestore is as easily discoverable as possible. For a list of the classes (i.e. RDF types) we have used you can run the following query
SELECT DISTINCT ?class WHERE { ?s a ?class . }
and the table it returns
-----------------------------------------------------
| class |
=====================================================
| <http://www.opengis.net/ont/geosparql#Geometry> |
| <http://www.w3.org/2006/time#DateTimeDescription> |
| <http://www.w3.org/2006/time#instance> |
| <http://www.w3.org/2006/time#TemporalEntity> |
| <http://www.opengis.net/ont/geosparql#Feature> |
| <http://www.w3.org/ns/prov#Location> |
| <http://www.w3.org/ns/prov#Entity> |
| <http://ocean-data.org/schema/DeploymentDataset> |
| <http://www.w3.org/ns/dcat#Dataset> |
-----------------------------------------------------
Investigating some other exploratory queries may also be useful to understand the data. The properties we have used in the data (i.e. how we describe the metadata) can be seen by running
SELECT DISTINCT ?nodb_properties WHERE { ?s ?nodb_properties ?o . }
which returns
---------------------------------------------------------------
| nodb_properties |
===============================================================
| <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> |
| <http://www.opengis.net/ont/geosparql#asWKT> |
| <http://www.w3.org/2006/time#year> |
| <http://www.w3.org/2006/time#hour> |
| <http://www.w3.org/2006/time#timeZone> |
| <http://www.w3.org/2006/time#dayOfYear> |
| <http://www.w3.org/2006/time#day> |
| <http://www.w3.org/2006/time#second> |
| <http://www.w3.org/2006/time#minute> |
| <http://www.w3.org/2006/time#unitType> |
| <http://www.w3.org/2006/time#month> |
| <http://www.w3.org/2006/time#dayOfWeek> |
| <http://www.w3.org/2006/time#inDateTime> |
| <http://www.w3.org/2006/time#inXSDDateTime> |
| <http://www.w3.org/2006/time#hasEnd> |
| <http://www.w3.org/2006/time#hasBeginning> |
| <http://www.opengis.net/ont/geosparql#hasGeometry> |
| <http://www.w3.org/2003/01/geo/wgs84_pos#lon> |
| <http://ocean-data.org/schema/hasParameter> |
| <http://www.w3.org/ns/prov#atLocation> |
| <http://mmisw.org/ont/ioos/biological#maximumDepthInMeters> |
| <http://mmisw.org/ont/ioos/biological#minimumDepthInMeters> |
| <http://ocean-data.org/schema/fromInstrument> |
| <http://www.w3.org/2004/02/skos/core#notation> |
| <http://www.w3.org/ns/dcat#distribution> |
| <http://www.w3.org/2003/01/geo/wgs84_pos#lat> |
| <http://ocean-data.org/schema/hasDateTimeCoverage> |
| <http://www.w3.org/ns/prov#wasAttributedTo> |
---------------------------------------------------------------
Finally, given that the data series have been given the rdf:type of <http://www.w3.org/ns/dcat#Dataset>, it’s useful to know the properties that are applicable only to instances of this class; this can be done using the following query
SELECT DISTINCT ?class_properties
WHERE {
?s a <http://www.w3.org/ns/dcat#Dataset>;
?class_properties ?o .
}
Which returns
---------------------------------------------------------------
| property |
===============================================================
| <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> |
| <http://www.w3.org/2006/time#hasEnd> |
| <http://www.w3.org/2006/time#hasBeginning> |
| <http://www.w3.org/2003/01/geo/wgs84_pos#lon> |
| <http://ocean-data.org/schema/hasParameter> |
| <http://www.w3.org/ns/prov#atLocation> |
| <http://mmisw.org/ont/ioos/biological#maximumDepthInMeters> |
| <http://mmisw.org/ont/ioos/biological#minimumDepthInMeters> |
| <http://ocean-data.org/schema/fromInstrument> |
| <http://www.w3.org/2004/02/skos/core#notation> |
| <http://www.w3.org/ns/dcat#distribution> |
| <http://www.w3.org/2003/01/geo/wgs84_pos#lat> |
| <http://ocean-data.org/schema/hasDateTimeCoverage> |
| <http://www.w3.org/ns/prov#wasAttributedTo> |
---------------------------------------------------------------
If you’d like any further advice on queries that can be executed to help explore the data, please get in touch.
Note
We currently set a limit of 60 seconds for the execution time of any query. If you find that this is too restrictive, please contact us so that we can build a better idea of the service the community wants
Tip
We currently have an installation of elda installed, so that URIs are resolvable to a real webpage. However, this should be considered as a beta service, and so may change without warning
