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Adding a concept

To add a concept to the diagram, click the Concept tool in the left panel.

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Then move your mouse over to the canvas and click again to release the concept onto the canvas. A concept with the label New Concept will be added to the diagram.

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Concept element

Let’s take a closer look at a concept element. The element displays a default label, New Concept.

To name the concept, double-click on it and enter the name.

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The lower part of the element indicates the number of Attributes for this concept. Initially, this value is 0.

Click the 04-05-plus-button.png button on the right of the element to display the menu.

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You can learn more about these menu items in:

Detailed concept information

If a concept has the focus, the detail information panel will contain information about that concept. You can edit the Preferred Label in the detail panel and on the canvas. However, only in the panel can you enter a Description, view and edit Mappings, and change the icon Color.

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Preferred Label

The default Preferred Label, or name, for all new concepts is "New Concept". To change the label, double click on the concept on the canvas, enter the new name, and hit the Return key. If the concept already had a preferred label you will be asked if you want to change the IRI to match the new label.

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More information on the the IRI and naming conventions can be found here.

Note

Changes to the preferred label also appear in the Detailed Concept Information panel and the IRI.

Description

In the Description field on the information panel, you can enter a description of the concept.

Note

The description exports as an rdfs:comment:

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Add a concept instance

To add a concept instance, click the + button on the concept, and then choose Add Instance from the menu.

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The concept element will now include a second ring to indicate that another instance has been added.

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In the Concept Information Panel, click to expand the Instances section and add a Preferred Label and Description for this instance.

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Color

You can change the color of the element, either in the Detailed Concept Information panel or in the Concept Element menu.

Note

Color information is not exported.

Copy the link to a concept

You can capture the URL link that navigates directly to a specific concept in your knowledge graph.

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To test the link, open a new tab in your browser and paste the link. After a moment, the document will open in Grafo and zoom in directly to the specific concept.

Note

You can share this link with others. If they are not Grafo users, they will need to create an account to view the document.

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Export a concept to a PNG file

You can export a single concept as a PNG image file. Click the + button on the concept, and then choose Export Concept as PNG from the menu.

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Look in the Downloads folder on your local computer for a PNG file with a name that includes both your document name and part of the Preferred Label of the concept.

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Advanced tab

Click the small down-arrow in the bottom-right of the Detailed Concept Information panel to display more information. Here you can edit the IRI and add Custom Fields.

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IRI

The default IRI for a conceis the Document IRI followed by the concept label and a random string. When the Preferred Label is changed for the first time, the IRI automatically changes to correspond to the new label. For any subsequent changes to the label, a prompt will appear to optionally update the IRI. If a new concept is given the same label as an existing concept, the IRI of the new concept will automatically have a random string appended to it (to ensure it is unique).

Note

The IRI of an attribute and the IRI of a relationship behave differently. The default behavior is to reuse the IRI if a new element is given the same label as an existing element.

Using a prefix in the Preferred Label

Default or custom prefixes can be used in the Preferred Label to set the IRI for the element. For example, if you are using the Person concept from the foaf vocabulary you might use "foaf:Person" for the label. When the IRI is updated, the IRI field will change to include the full IRI of the concept (/foaf/spec/person). See the figure below.

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This naming convention also works for any custom prefixes.

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Custom Fields

Custom fields can be added to your knowledge graph. For example, if you are working on a knowledge graph about dogs and you have a concept with a Preferred Label of "Dog", you could add the Latin word for "dog" as a custom field for the concept.

To Add Custom Field select the menu option:

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Type in the name of the field and select Enter.

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The new field is shown in the Advanced section.

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To enter a value for the field select the field name from the menu, enter your value, and hit Enter.

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Exporting custom fields

Custom fields are exported as an annotation property:

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This annotation property will be attached to the Dog class:

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Additional options for other elements

Additional options will appear in the Detailed Concept Information panel for concept attributes and relationships.

Concept export type

Concepts are exported as owl:Class.

Delete a concept

Caution

If you delete a concept, you cannot recover it.

There are two ways to delete a concept. you can either select the concept and click Delete and then OK in the popup window:

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or you can select the + menu on the concept and choose the last option, Delete Concept:

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