Diagrams for RDF data - PROV-O

The PROV-O ontology is a standard for representing provenance information. The primer contains conventions to visualize provenance graphs.

Nodes

The core classes are prov:Entity, prov:Activity, and prov:Agent. Each instance should be rendered as a node with a specific shape and color. This is easily achieved with N3 rules:

        
{
  ?entity a prov:Entity
}
=>
{
  v:digraph v:hasNode ?entity .
  ?entity attr:shape "oval" ;
    attr:color "#808080" ;
    attr:style "filled" ;
    attr:fillcolor "#FFFC87" .
} .
        
      

        
{
  ?activity a prov:Activity
}
=>
{
    v:digraph v:hasNode ?activity .
    ?activity attr:shape "box" ;
    attr:color "blue" ;
    attr:style "filled" ;
    attr:fillcolor "#9FB1FC" .
} .
        
      

        
{
  ?agent a prov:Agent
}
=>
{
  v:digraph v:hasNode ?agent .
  ?agent attr:shape "house" ;
    attr:color "black" ;
    attr:style "filled" ;
    attr:fillcolor "#FED37F" .
} .
          
      

Two additional rules provide a short node label (extracted from the URI) and a clickable link for dereferencing the URI:

      
{ v:digraph v:hasNode ?n . ?n log:localName ?localName } => { ?n attr:label ?localName } .

{ v:digraph v:hasNode ?n . ?n log:uri ?uri } => { ?n attr:URL ?uri } .        
      
    

The following triples:

      
ex:dataset1 a prov:Entity .
ex:compose1 a prov:Activity .
ex:derek a prov:Agent .
      
    

produce the following nodes:

Edges

Edges are created between nodes related by predicates in the PROV-O namespace:

      
{ 
  v:digraph v:hasNode ?n1, ?n2 .
  ?n1 ?p ?n2 .
  ?p log:namespace "http://www.w3.org/ns/prov#"; 
    log:uri ?uri ;
    log:localName ?localName .
} 
=> 
{
  v:digraph v:hasEdge [ 
    v:source ?n1; 
    v:target ?n2 ; 
    attr:label ?localName ;
    attr:labelURL ?uri ; 
    attr:tooltip ?uri
  ]
} .
      
    

      
{} => { v:digraph v:graphAttributes [ attr:rankdir "BT" ] } .
      
    

The rendering of this example from the specification looks very similar to the original:

Qualified properties

Some PROV-O relations can be qualified with a role. Instead of a simple prov:used relationship between an activity and an entity, it's possible to have a prov:qualifiedUsage link to a prov:Usage node having a prov:hadRole property:

      
ex:dataset1 a prov:Entity .
ex:compose1 a prov:Activity . 

ex:compose1 prov:qualifiedUsage [ 
    a prov:Usage ; 
    prov:entity ex:dataset1 ; 
    prov:hadRole ex:dataToCompose 
] .
      
    

In the conventional rendering, the activity and the entity are directly connected by an edge with label used, and this edge has an outgoing dashed edge to a note-shaped node labeled with the role. Graphviz does not support edges pointing at other edges, but we can use a small invisible node to achieve a similar effect:

      
{
  ?activity prov:qualifiedUsage [ prov:entity ?entity ; prov:hadRole ?role ] .
  ?role log:localName ?roleName .
  ("prov:hadRole=\n" ?roleName) string:concatenation ?roleLabel .
} 
=> 
{
  _:hidden attr:shape "point"; attr:width "0"; attr:height "0"; attr:xlabel "used" .
  v:digraph v:hasNode _:hidden . 
  v:digraph v:hasEdge [ v:source ?activity; v:target _:hidden; attr:dir "none"] .
  v:digraph v:hasEdge [ v:source _:hidden; v:target ?entity] .
  _:role attr:shape "note"; attr:label ?roleLabel .
  v:digraph v:hasNode _:role .
  v:digraph v:hasEdge [ v:source _:hidden; v:target _:role; attr:dir "none"; attr:style "dashed"] .
} .
      
    

While the hidden intermediate node makes the edge not as smooth as desired, we still obtain a visualization close enough to the original

The full set of PROV-O visualization rules is available in the repo. You can load that .n3 file as custom rules in the playground tool to visualize your own PROV-O datasets.