The Explore module provides a generic and extensible RDF data browser and editor.Use the Explore module to browse through your resources, to change between list and detail views and to edit resources.

To open the Explore module, click EXPLORE in the Module bar.

The user interface of the Explore module shows the following elements:

The main window provides multiple views depending on what resource has been selected. If necessary, you can hide the Graphs and Navigation boxes: To hide the boxes, click  in the upper left corner. To show the boxes again, click .


The Graphs box shows the list of graphs you have access to. A Lock icon  indicates that you have only read access to this graph and are not allowed to edit data of this graph. To select a graph click the graph name in the Graphs box. The structure of the selected graph is displayed in the Navigation box below. On the right window, the Metadata view of the selected graph appears showing several tabs with metadata information.

Adding a new graph

To add a new graph to the Graphs list:

  • In the Graphs box, click the menu.
  • Click Add new graph. A dialog box appears.
  • Enter the graph URI (e.g. for the new graph.
  • Optional: Click Choose file to upload a file containing the graph data. You can upload one of the following file formats: Turtle, N-Triples, RDF/XML, or JSON-LD.
  • Click ADD GRAPH to save the new graph.

Note: When adding a new graph you can enter only a URI and skip the upload step. You can upload a file at a later date using the Managing a graph option.

Downloading a graph

To download a graph from the Graphs list:

  • In the Graphs box, select the graph you want to download.
  • In the Graphs box, click the menu .
  • Click Download graph. A message box appears, stating that downloading can take a long time.
  • Click DOWNLOAD.

Managing a graph

Use this function to add updated data to a graph, to replace data or to delete a graph.

To update or replace data of a graph:

  • In the Graphs box, select the graph you want to update or replace.
  • In the Graphs box, click the menu .
  • Click Manage graph. A dialog box appears.
  • Click Choose file to upload a file containing the new or updated data. You can upload one of the following file formats: Turtle, N-Triples, RDF/XML, or JSON-LD.
  • Choose one of the following options:
    • Update: add uploaded data to Graph.
    • Replace: clear Graph and add uploaded data.
  • Click UPDATE to save your changes.

To delete the graph click the Delete icon  and confirm or cancel the deletion process.


When a graph is selected in the Graphs box the structure of the graph is displayed in the Navigation box. By default, only the top classes of the graph are listed. An arrow  indicates that a class has subclasses. Click the arrow to show the subclasses.

Use the Search field of the Navigation box to search for a keyword in the navigation structure of the graph. Enter a keyword and press Enter to start the search. To reset the results delete the keyword and press Enter.

Instance List of a class

Select a class in the Navigation box to show all instances of this class in the Instance List on the right window.

Instance List of a class

Click  or use the  menu in the upper right corner to add a new resource to the graph.

Use the settings menu  to adjust the table view. You can also use the buttons next to the column titles to change alphabetical order, set filter criteria or hide the column from the table view.

Custom Instance List

The table uses a default query to list all resources with a given class.

For more complex representations, it is possible to customise the view adding a triple of the form 

     <ShaclShapeURI> <> <sparqlQueryURI> 

The sparqlQueryURI has a queryText which can contain the following placeholders: {{FROM}}.

For example, having the following shape associated to PropertyShape:

     <> <> <> 

and adding the following triples:

     <> <> <> .

      a <> ;
      <> "Shape Shapes: UI query for listing property shapes" ;
      <> "\nPREFIX rdfs: <>\nPREFIX shacl: <>\nPREFIX shui: <>\nSELECT DISTINCT ?propertyShape ?path ?description\n{{FROM}}\nWHERE\n{\n ?propertyShape a shacl:PropertyShape .\n OPTIONAL { ?propertyShape shacl:path ?path }.\n OPTIONAL { ?propertyShape shacl:description ?description }.\n FILTER isIRI(?propertyShape)\n}\n" ;
      <> "SELECT" .
will result in an custom Instance List for the class <>:

Instance Details

To open the Instance Details of a resource click on that resource in the Instance List. Resources are shown as grey buttons.

Use  on the right upper corner to remove the resource. A dialog box appears where you are asked to confirm the operation.

Note: When you remove the resource all triples related to that resource are deleted too.

The instance data is provided on the following tabs:

Instance Details of a resource

Metadata of graphs

To display metadata of a graph, select a graph in the Graph box on the left side. In the main window you see the metadata arranged in the following tabs:

Note: The Usage tab is only displayed when it contain data.


The Information tab provides the following metadata of a graph:

  • Abstract: Describes the content or purpose of the graph
  • Authors: Lists the authors of the graph
  • Publisher: Shows the publisher of the graph
  • License: License information of the graph
  • Current Version: Current version number of the graph
  • Date of Last Modification: Date when the graph was last modified
  • Preferred Namespace: Preferred namespace and URI, like
  • Preferred namespace prefix: is used as a (short)reference in SPARQL queries
  • Namespaces: Lists the namespaces used by the graph
  • External Links: Links to internet resources: homepages, pages, SPARQL endpoints or data dumps
  • Creation Date: Creation date of the graph
  • Issued: Publication date of the graph

The property Namespaces shows only those namespaces that are specified by the respective property. But it is possible that the graph actually uses more namespaces than indicated.

Note: The descriptions given comply with the intended usage of the respective properties. But in practice these properties are often used with a wrong content. Therefore in some cases the description given may not correspond to the actually displayed metadata of a graph.


This tab shows all properties and objects of the selected resource.

Properties tab

Use the icons on the right side to edit or delete properties. Use SHOW IN LIST to display objects in a list view. Click ADD to add a new value as an object to a property. In the dialog box, select the type from the drop-down list and enter the value. Click SAVE to save your changes.

To add a new property click . In the dialog box, enter a property, select the value type from the drop-down list and enter a value. Click SAVE to save your changes.


This tab allows the user to explore data using Ontodia library.

More information about Ontodia in its official web page.


The Statistics tab indicates the number of classes, properties, entities and triples of the graph. To show these values the application uses by default the VoID Statistics contained in the graph.

Statistics tab

Use  Update VoID statistics to update the values with a new query. Depending on the size of the graph this operation can take some time.

Use  Save to save updated VoID statistics in the graph. The Save button can only be used when an update query was executed before or when the option auto fetch VoID Statistics is activated. Saving VoID statistics does not modify the property Date of Last Modification.

In order to display the metadata of a graph various properties are analysed that are contained in the graph itself. If these properties are missing in the graph, some metadata properties may remain empty. These empty properties are hidden by default.

Note: If you leave this module or even the view, this option is reset to the default setting.
Note: The values given in VoID Statistics can be obsolete. If the graph does not contain the required VoID Statistics no value is displayed.


The Visualization tab shows a visual graph representation of the ontology concepts in a graph selected in the Graphs box.

It displays ontology classes as circle-shaped nodes, which are connected by directed, labelled edges (arrows) representing properties. Classes defined by the ontology are colored light blue. External, referenced classes are colored dark blue and have the additional label “(external)”. You can zoom in and out of the graph using your mouse wheel or “pinching”, if you have a touch screen or touch pad. You can drag the canvas by left-clicking the canvas, holding the click and moving the mouse.

General concept with object property

For example, two circles “Business entity” and “Civic structure” represent two classes of objects in an ontology. An edge with a light blue box labelled “operated by” pointing from “Civic structure” to “Business entity” means, that there is an object property “operated by” in the ontology whose domain and range are “Civic structure” and “Business entity” respectively. If there are instances of the classes in question, the number of instances are shown in the node, directly under the label.

Dotted edges with empty arrow heads are always labelled “Subclass of”. They signify rdfs:subClassOf relationships defined between the classes connected by the edge.

For example, a “Subclass of”-edge pointing from a circle “Parking facility” to a circle “Civic structure” means, that the ontology defines a “Parking facility” class which is a subclass of the “Civic structure” class.

General concept with datatype property

Edges connecting circles with rectangles signify data properties. They are labelled in light green. The label of the rectangle they connect to signifies the datatype of the property.

For example an edge labelled “vehicle length limit” connecting a circle “Civic structure” with a rectangle “decimal” represents a data property “vehicle length limit” with domain “Civic structure” and range (datatype) “decimal.


The ontology visualization interface provides a number of features to browse, search and modify the visualization.

The Search box allows searching for ontology concepts like classes or properties with auto-complete. Selecting one of the recommended concepts after typing will draw an attention to the concept in the visualization by drawing a red marker around it. You can also focus the visualization on the concept by clicking LOCATE. The visualization then zooms and centers on the selected concept.

Interface showing LOCATE function


The FILTER button displays a context menu that lets you filter (remove) specific concepts from the diagram to provide a better overview.

You can also collapse the ontology, pruning less important concepts from the visualization. Higher degrees of collapsing equal fewer, but more important concepts being shown. Importance of concepts is derived from their interconnectedness, their number of subclasses and number of connected properties.


The MODES button displays a context menu that allows you to configure the behavior of the visualization.

Dynamic label width, if enabled, scales node and edge labels so that the full label is displayed. This can be detrimental if the ontology features excessively long labels.

Pick & pin, if enabled, allows you to select specific nodes and “pin” them to the visualization canvas, stopping them from moving. This allows you to rearrange the concepts effectively and shape the visualization to your needs.

Node scaling, if enabled, scales nodes if they have a larger number of instances.

Compact notation, if enabled, removes “Subclass of” label from “Subclass of”-edges and the “(external)” label from external class nodes.

Color externals, if enabled, colors external, referenced classes in dark blue.


The EXPORT button displays a context menu that allows you to either export the complete visualization as a JSON file or the current visualization as an SVG file. Only the part of the canvas shown to you will be as SVG. Parts of the canvas that are hidden (for example by zooming or browsing) are not saved to the SVG image file.


The GRAVITY button displays a context menu that allows you to manipulate the distance between nodes.


The RESET button resets the visualization to its default setting.


The PAUSE button switches off the force-directed layout, freezing the whole graph in place. Like the “Pick & pin” mode, this enables you to rearrange concepts effectively, without other concepts “swimming” too far or getting in your way. Unlike the “Pick & pin” mode, this applies to the whole graph, not only concepts you picked. You can RESUME the force-directed layout to return to the default behavior.


This tab shows all properties that use the selected resource as an object.

References tab


This tab shows the turtle RDF representation of the raw data representing the resource. You can use this tab to edit the selected resource:

  • Enter your changes in turtle.
  • Add a changelog comment (optional).
  • Click UPDATE to save your changes.

Deleting the entire turtle representation deletes the resource.


This tab shows a table with the list of changes made in the Resource. To see the tab:

  • History needs to be enabled in configuration.
  • A Versioning Graph needs to be assigned to the graph where the Resource is saved.


The Usage tab is only available when the Instance Details of a property is displayed because this tab shows all subjects and objects of a selected property.