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Ontospy is a lightweight Python library and command line tool for inspecting vocabularies encoded in the RDF family of languages .
Note: as of version 1.8, Ontospy includes only the core Python API for manipulating ontologies - all the visualization functionalities have been moved to the OntoDocs library.
Ontospy can be used either as an interactive command line interface (a repl) or as a Python package.
Calling the ontospy command from a terminal window launches a utility for scanning a knowledge model encoded in RDF (or any of its dialects e.g. RDFS, OWL or SKOS).
For example, if you pass a valid graph URI e.g.
ontospy http://purl.org/spar/frbr
Ontospy will attempt to extract and print out any ontology-related information contained in that graph.
Many other options are available, in particular Ontospy allows to load/save ontologies from/to a local repository so that they can be cached and quickly reloaded for inspection later on. All without leaving your terminal window!
If used as a Python package, the basic workflow is the following: load a graph by instantiating the Ontospy class with a file containing RDFS, OWL or SKOS definitions; you get back an object that lets you interrogate the ontology. That's all!
Let's take a look at the Friend Of A Friend vocabulary.
In [1]: import ontospy
INFO:rdflib:RDFLib Version: 4.2.0
In [2]: model = ontospy.Ontospy("http://xmlns.com/foaf/0.1/")
----------
Loaded 631 triples from <http://xmlns.com/foaf/0.1/>
started scanning...
----------
Ontologies found...: 1
Classes found......: 14
Properties found...: 67
Annotation.........: 7
Datatype...........: 26
Object.............: 34
SKOS Concepts......: 0
----------
In [3]: model.classes
Out[3]:
[<Class *http://www.w3.org/2003/01/geo/wgs84_pos#SpatialThing*>,
<Class *http://xmlns.com/foaf/0.1/Agent*>,
<Class *http://xmlns.com/foaf/0.1/Document*>,
<Class *http://xmlns.com/foaf/0.1/Group*>,
<Class *http://xmlns.com/foaf/0.1/Image*>,
<Class *http://xmlns.com/foaf/0.1/LabelProperty*>,
<Class *http://xmlns.com/foaf/0.1/OnlineAccount*>,
<Class *http://xmlns.com/foaf/0.1/OnlineChatAccount*>,
<Class *http://xmlns.com/foaf/0.1/OnlineEcommerceAccount*>,
<Class *http://xmlns.com/foaf/0.1/OnlineGamingAccount*>,
<Class *http://xmlns.com/foaf/0.1/Organization*>,
<Class *http://xmlns.com/foaf/0.1/Person*>,
<Class *http://xmlns.com/foaf/0.1/PersonalProfileDocument*>,
<Class *http://xmlns.com/foaf/0.1/Project*>]
In [4]: model.properties
Out[4]:
[<Property *http://xmlns.com/foaf/0.1/account*>,
<Property *http://xmlns.com/foaf/0.1/accountName*>,
<Property *http://xmlns.com/foaf/0.1/accountServiceHomepage*>,
<Property *http://xmlns.com/foaf/0.1/age*>,
<Property *http://xmlns.com/foaf/0.1/aimChatID*>,
<Property *http://xmlns.com/foaf/0.1/based_near*>,
<Property *http://xmlns.com/foaf/0.1/birthday*>,
<Property *http://xmlns.com/foaf/0.1/currentProject*>,
<Property *http://xmlns.com/foaf/0.1/depiction*>,
### etc....
]
In [5]: model.printClassTree()
[1] http://www.w3.org/2003/01/geo/wgs84_pos#SpatialThing
[12] ----_file_:Person
[2] _file_:Agent
[4] ----_file_:Group
[11] ----_file_:Organization
[12] ----_file_:Person
[3] _file_:Document
[5] ----_file_:Image
[13] ----_file_:PersonalProfileDocument
[6] _file_:LabelProperty
[7] _file_:OnlineAccount
[8] ----_file_:OnlineChatAccount
[9] ----_file_:OnlineEcommerceAccount
[10] ----_file_:OnlineGamingAccount
[14] _file_:Project
In [6]: model.toplayer
Out[6]:
[<Class *http://www.w3.org/2003/01/geo/wgs84_pos#SpatialThing*>,
<Class *http://xmlns.com/foaf/0.1/Agent*>,
<Class *http://xmlns.com/foaf/0.1/Document*>,
<Class *http://xmlns.com/foaf/0.1/LabelProperty*>,
<Class *http://xmlns.com/foaf/0.1/OnlineAccount*>,
<Class *http://xmlns.com/foaf/0.1/Project*>]
In [7]: model.getClass("document")
Out[7]:
[<Class *http://xmlns.com/foaf/0.1/Document*>,
<Class *http://xmlns.com/foaf/0.1/PersonalProfileDocument*>]
In [8]: a_class = _[0]
In [9]: print(a_class.serialize())
@prefix ns1: <http://www.w3.org/2002/07/owl#> .
@prefix ns2: <http://www.w3.org/2003/06/sw-vocab-status/ns#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix xml: <http://www.w3.org/XML/1998/namespace> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
<http://xmlns.com/foaf/0.1/Document> a rdfs:Class,
ns1:Class ;
rdfs:label "Document" ;
rdfs:comment "A document." ;
rdfs:isDefinedBy <http://xmlns.com/foaf/0.1/> ;
ns1:disjointWith <http://xmlns.com/foaf/0.1/Organization>,
<http://xmlns.com/foaf/0.1/Project> ;
ns1:equivalentClass <http://schema.org/CreativeWork> ;
ns2:term_status "stable" .
In [10]: a_class.parents()
Out[10]: []
In [11]: a_class.children()
Out[11]:
[<Class *http://xmlns.com/foaf/0.1/Image*>,
<Class *http://xmlns.com/foaf/0.1/PersonalProfileDocument*>]
Here are some reasons why you should use it:
- You are developing a Python application that needs to extract schema information from an RDF, SKOS or OWL vocabulary.
- You have a bunch of RDF vocabularies you regularly need to interrogate, but do not want to load a full-blown ontology editor like Protege.
- You need to quickly generate documentation for an ontology, either as simple html pages or via some more elaborate interactive visualization (UPDATE: check out the OntoDocs library for this!).
- You love the command line and would never leave it no matter what.
note: Ontospy does not offer any ontology-editing features, nor it can be used to interrogate a triplestore.
- Github: https://github.com/lambdamusic/ontospy
- CheeseShop: https://pypi.python.org/pypi/ontospy
- Homepage: http://www.michelepasin.org/projects/ontospy
Also:
- Video: https://vimeo.com/169707591
- Check out the OntoDocs library which builds on OntoSpy and permits to quickly generate documentation like in these examples