The Ontology Editor lies at the heart of LegendBurster. It is used to define the structure which will underlie mapObject descriptions in LegendBurster, and which enables LegendBurster queries to operate much more thoroughly and "intelligently" than conventional database queries.
A description of ontologies, and their importance to knowledge bases, appears in an Appendix to this document, and can be viewed here.
This is a view of the Ontology Editor screen with all its features numbered. Clicking on any number will provide a description of that feature:
The Ontology Editor consists of these areas:
This is a list of all entities defined in the ontology. Entities are "classes of things", when working at the ontological level, and "things themselves" when working at the level of "instances" in a knowledge base. All LegendBurster ontologies start with two top-level classes of entities: "mapObject" and "query". One "mapObject" instance exists for each object on the map, and it is onto these mapObject entities that LegendBurster's descriptive semantic nets are attached. The "query" entity class exists to allow formulation of queries. A query instance exists for each query input into LegendBurster. Any top-level attribute created should be linked with these two entities (top level = "one which directly qualifies a mapObject").
Other attributes may qualify these top level attributes. To enable this hierarchical nesting of qualifiers, any attribute which needs to be qualified has first to be added to the Entity List (using the Create Entity button). <Return to Ontology Editor Screen>
This is the list of all attributes defined in the Ontology. Originally, this list is empty. Attributes are created to hold the attribute values which may be transferred from the DBF table attached to the shapefile, or which may be derived from other sources.
This is the list of all value domains defined in the Ontology.
This is the list of all values of a currently selected Attribute or Value Domain. It is originally empty, and only displays information when an Attribute or Value Domain is clicked on in (2) or (3).
This is the list of all Value Attributes of the currently selected Value. A Value Attribute is an attribute which an entity will have by virtue of its value in a class, rather than by virtue of which class it belongs to.
Value Attributes are described, with an example, in the section on "Working with Attributes".
(6) Entity-Attribute Link Control Buttons
This button is used to link an attribute (which must be selected in the Attributes column), with an entity (which must be selected in the Entities column). Linking an attribute to an entity will allow entities of that class to be qualified with the linked attribute when entering instance or query descriptions.
The linking action will pop up the following screen requesting selection of a "Link Type".
There are three types of links:
Primary:
Attribute
needs to be input by a user during instance description or query specification.
Inherited: Link required only to allow attributes to be propagated
(inherited) into the entity from elsewhere in a description. No
input of the attribute will be requested from the user.
Primary & Inherited: Attribute
can be input by a user, or can be inherited into place by the system.
The default setting of "Primary & Inherited" is recommended for all cases other than specialist applications involving "hetero-inheritance" that have been implemented with the assistance of Georeference Online Ltd.
This button is used to change the link-type existing between an attribute (which must be selected in the Attributes column), with an entity (which must be selected in the Entities column).
Please refer to the description of link-types under Topic 6 of this description of the Ontology Editor.
Attributes in LegendBurster are effectively the names given to relationships between the entity they describe the value of the attribute. For example: Entity="mine"; Attribute="HasEnhancedConentrationOf"; Value = "gold".
The understanding of an ontology by users other than those who designed it is often enhanced by explicitly declaring the name of the inverse relationship. (In some ontogically-based systems, the inverse relationship may be used during processes on the ontology. In LegendBurster, this is true only for Referring Attributes.)
The name of the inverse attribute for the above example might be something like "Occurs at an enhanced concentration in".
Inverse attributes may be input only when creating an attribute.
The only kind of attribute which requires an inverse attribute is a "referring attribute", as described in the section on "Working with Attributes".
If an icon has been associated with an attribute, it will be displayed here when the attribute is selected in the Attribute column.
These radio buttons allow choice between viewing all entities, or viewing only entities linked with the currently selected attribute.
(11) Attribute Display Filters
These radio buttons allow choice between:
(a) viewing all attributes,
(b) viewing only attributes linked with the currently selected entity,
(c) viewing only attributes that take
their values from the currently selected value domain,
(d) viewing only attributes that aren't linked with any entities yet.
(12) Value Domain Display Filters
These radio buttons allow choice between viewing all value domains, or viewing only the value domain of the currently selected attribute.
(13) Entity Creation and Removal Buttons
Pops up a browse window that searches for .ico files that can be associated with the attribute, and displays the icon in the Semantic Net Editor, and the Query Manager.
Entity, attribute and link comments may be viewed and edited in a different format by clicking on this button. (See also area (18)).
(15) Attribute Creation and Removal Buttons
Other tools available in the Ontology Editor for the creation of:
Slots
Hetero - Hierarchies Inheritance (Not implemented in this version. Please contact Georeference Online Ltd if you believe that you may need this functionality.)
After defining the ontology for a particular field, the user should create semantic nets for all polygons.
After this, the user could begin formulating queries, or go to a different field in the shape file, and begin the sequence again - WordList Editor, Ontology Editor, Semantic Net Editor.
Value domains may be imported <Find out more> from other LegendBurster projects using this button.
(17) Edit, Import, Export Values Button
This button will start the Values Editor <Find out more>, which will be loaded with the values of the attribute selected in the Attributes column.
(18) Notes on Entities, Attributes and Links
In this region, any descriptive comments on the currently selected entity and attribute are displayed, as well as any comment on the relationship between them. These comments may be edited by clicking on their respective "Edit" buttons. The comments may be viewed and edited in a different format from button (14).
(19) The Ontology Editor Main Tab
This tab connects to the main Ontology Editor screen. Clicking on it while viewing any other Ontology Editor screen will return control to the main screen.
The Manage Slots tab shifts control to the "Manage Slots" screen. Use of this facility is reserved for expert users of the Ontology Editor who are experienced knowledge engineers. It is not a supported component of this version of LegendBurster. If you believe that you have a need for slots and inherited default values in your knowledge base, please contact Georeference Online Ltd at support@georeferenceonline.com and we will be happy to assist you to implement your requirements.
The Set Slot Values tab shifts control to the "Set Slot Values" screen. Use of this facility is reserved for expert users of the Ontology Editor who are experienced knowledge engineers. It is not a supported component of this version of LegendBurster. If you believe that you have a need for slots and inherited default values in your knowledge base, please contact Georeference Online Ltd at support@georeferenceonline.com and we will be happy to assist you to implement your requirements.
(22) The Hetero-Inheritance Tab
The Hetero-Inheritance tab shifts control to the "Hetero-Inheritance" screen. Use of this facility is reserved for expert users of the Ontology Editor who are experienced knowledge engineers. It is not a supported component of this version of LegendBurster. If you believe that you have a need for inheritance of values in your knowledge base, please contact Georeference Online Ltd at support@georeferenceonline.com and we will be happy to assist you to implement your requirements.
(23) The Attribute Hierarchies Tab
The Attribute Hierarchies tab shifts control to the "Attribute Hierarchies" screen. Use of this facility is reserved for expert users of the Ontology Editor who are experienced knowledge engineers. It is not a supported component of this version of LegendBurster. If you believe that you have a need for slots and inherited default values in your knowledge base, please contact Georeference Online Ltd at support@georeferenceonline.com and we will be happy to assist you to implement your requirements.
The Graphical View tab shifts control to the "Graphical View" screen which provides a graphical view of the ontology.
Proceed to MapObject Net Editor