Browse through this FAQs to find answers to commonly raised questions about Loterre.
Loterre (acronym for Linked open terminology resources) is a platform for exposing and sharing multidisciplinary and multilingual scientific terminology.
Based on a triplestore, it complies with open and linked data (LOD) web standards and FAIR principles, which aim to make data Easy to find, Accessible, Interoperable and Reusable.
The terminology available in Loterre can meet the needs of text-mining, semantic annotation, information retrieval or translation.
Access to the resources sotred in Loterre is open to all, with the subsequent use of each one being linked to the license that governs it.
Loterre gives access to scientific terminology resources and allows:
Loterre also offers online services, the content of which is detailed in the “Loterre services” paragraph of this page.
Loterre is not restricted to Inist terminological resources. It offers its services to other producers of terminological data, provided they have requested the service using the proposition form.
Interested producers are invited to read the Loterre Charter.
The FAIR principles (Findability, Accessibility, Interoperability, Reusability) applicable to the scientific data were developed by Force11 and published by Wilkinson et al. in 2016 (The FAIR Guiding Principles for scientific data management and stewardship). The steps involved in FAIRification have been explained by GO FAIR.
These principles form a guide to good practice for the management and reuse of data and metadata by both machines and humans. However, they do not constitute a specification because they do not recommend any particular standard, technology or data format.
In addition, FAIR data are not necessarily “open” and may have different degrees of FAIRness and/or openness. LOD (based on semantic web standards) and FAIR (based on principles) should not be confused: see on this subject “Cloudy, increasingly FAIR; revisiting the FAIR Data guiding principles for the European Open Science Cloud” (2017)
The terminology (meta)data presented in Loterre meets all the FAIR principles. Indeed, they are:
They can also participate in the FAIRification of (meta)research data by promoting their semantic interoperability (through vocabulary or thesaurus concepts).
Similarly, the Check, Transform and Align services aim to facilitate the creation and enrichment of terminology in SKOS/RDF-XML format according to FAIR practices.
Loterre and the Inist terminologies that the platform hosts are reported in the FAIRSharing portal: https://fairsharing.org/collection/Loterre
Loterre aims to comply with the principles of LOD (Linked Open Data) as presented in 2006 by W3C (Tim Berners-Lee): terminology resources are considered here as organized sets of terms (designating concepts) that are freely accessible via semantic web technologies.
Linked Data or “web of linked data” is based on 4 basic rules:
By adding open licenses for the distribution and reuse of resources published on the web, Loterre complies with the rules of “Linked Open Data”.
T. Berners-Lee also proposed a progressive classification of LODs with 5 stars according to the following criteria:
* Data freely available on the web, with mention of an open license
** Data in a structured, machine-readable format
*** Non proprietary formats (CSV, JSON, …)
**** W3C open standards (RDF, XML, SPARQL) and URI as resource identifier
***** Data linked to other RDF data via alignments in the LOD Cloud
Finally, the resources integrated into the triplestore are intended, as far as possible, to comply with W3C best practices for the publication of related data (W3C, 2014).
All the resources exposed in Loterre are compatible with these rules and principles and can be classified as 4 or 5 stars:
It is aimed, wherever possible, that the resources integrated into the triplestore conform to good practices of the W3C relative to the publication of linked data.
Ideally, they should respect the criteria allocated to “5 star” data: Linked Data – Design Issues
Schematically, the terminological resources exposed on Loterre can be of the type:
The data of lexical resource types, resources of content or ontology analyses, can only be integrated into Loterre if they are converted into the SKOS format, which can involve a loss of information compared to the original content.
The resources may:
The resources exposed in Loterre may:
The possibilities of posting and searching in a given language are linked to the characteristics of exposure/queries tools connected to the triplestore.
The resources exposed in Loterre must have a license authorizing the availability and reuse of data, such as:
The terminological data integrated in the triplestore are expressed according to a model of the type “extended SKOS”, which associates a certain number of categories belonging to other formats or languages (SKOS-XL, Dublin Core, Isothes, OWL, RDFS, etc.) to the SKOS standard.
Ontology of Loterre (click on the picture to reduce it)
Terminologies proposed by third parties are subject to a review based on quality and format criteria. The owners of the Loterre site reserve the right to moderate the proposals received. They may refuse to integrate a terminology if they consider that it does not meet the criteria governing the platform.
The scientific cover of data exposed on Loterre is multidisciplinary and depends on one or several of the following scientific fields:
The architecture of Loterre is based on a triplestore connected with a browsing tool and searchable via a SPARQL interface and an API.
To offer its users access to terminologies, Loterre calls upon various open-source tools:
Loterre was designed by the Inist-CNRS
In addition to downloading terminological data, Loterre offers a range of services for terminology producers, whether or not they want to share their work in Loterre.
The Check, Transform and Align services aim at facilitating the creation and enrichment of SKOS/RDF-XML terminological files, in accordance with the FAIR data principles (Findable, Accessible, Interoperable, Reusable).
n.b.: The user data are not stored by Inist-CNRS.
This service aligns (maps) a valid SKOS/RDF-XML file (source) with a Loterre terminology resource (target) specified by the user.
It checks whether a term (preferential or synonymous) of a concept A of the source vocabulary is identical to a term (preferential or synonymous) of a concept B of the target vocabulary (for the same language code). It processes files containing “skos:Concept” (short form of the RDF/XML syntax) or “rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#Concept’]]”.
Note that alignment is based on a comparison of strings, which must be identical on both sides, without taking into account the context; the alignments will therefore have to be validated by the user.
2 variants of this service are available:
The records in the alignment file can be added as they are at the beginning or end of the source file.
The “Annotate” service allows you to search, in a portion of text written in French, English or Spanish, for the presence of terms (preferred labels and synonyms) from a terminology hosted in Loterre.
It displays the text in which the detected terms have been highlighted and a table of corresponding terms and concepts, with their URI.
The “Transform” service enables to obtain terminology in SKOS-XML format or to convert a terminology initially in SKOS-XML format into another format.
The modules offered by this service can be grouped into three types: correction, enrichment and conversion.
These modules are in particular intended to correct anomalies previously detected by the “Control” service.
Files containing “skos:Concept” or “rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#Concept’]]” are processed by this service.
At the level of each concept, this service operates as follows:
At the end of this process, check the file again using the Controlling a SKOS/RDF-XML file at the concept level service to ensure that there are no more duplicates.
Files containing “skos:Concept” or “rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#Concept’]]” are processed by this service.
If a concept A is associated to a concept B through the skos:related property, the concept B must be associated with the concept A because the relation is symmetrical. Cf. SKOS Reference (Axiom S23).
If this condition is not checked, this service allows inserting the missing “skos: related” property.
Note that this treatment does not apply to any sub-properties of the skos: related property.
Files containing “skos:Collection” or “rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#Collection’]]” or “rdf:Description[rdf:type[@rdf:resource=’http://purl.org/iso25964/skos-thes#ConceptGroup’]]” are processed by this service.
The hierarchical relationship between a collection A and a collection B is expressed using the “isothes:superGroup” property. The presence of an “isothes:subGroup” property (which is the inverse relationship) at the level of collection B is not mandatory because it is inferred from the “isothes:superGroup” property.
However, the proper functioning of some applications (like Skosmos) requires the presence of both relationships. This service allows to insert at the level of the broader collection as many “isothes:subGroup” properties as narrower collections of this collection.
Files containing “skos:Concept” or “rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#Concept’]]” are processed by this service.
This service inserts two classes at the beginning of a SKOS/RDF-XML file:
– a “cc:License” class with the default CC-BY 4.0 Creative Commons license that should be changed if the resource is released under a different license.
– a “skos:ConceptScheme” or “rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#ConceptScheme’]]” class with:
After the fields have been generated, their textual content must be completed and validated by the user.
Files containing “skos:ConceptScheme” or “rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#ConceptScheme’]]” are processed by this service.
This service inserts a “skos:hasTopConcept” property into the “ConceptSCheme” block for each concept that does not have a “skos:broader” property.
Do not use this service for unstructured or loosely structured resources.
Files containing “skos:Concept” or “rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#Concept’]]” are processed by this service.
This service inserts a “skos:topConceptOf” property into each concept that does not have a “skos:broader” property.
Do not use this service for unstructured or loosely structured resources.
Files containing “skos:Collection” or “rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#Collection’]]” or “rdf:Description[rdf:type[@rdf:resource=’http://purl.org/iso25964/skos-thes#ConceptGroup’]]” are processed by this service.
The hierarchical relationship between a collection A and a collection B is expressed using the “isothes:superGroup” property. The presence of an “isothes:subGroup” property (which is the inverse relationship) at the level of collection B is not mandatory because it is inferred from the “isothes:superGroup” property.
However, the proper functioning of some applications (like Skosmos) requires the presence of both relationships. This service allows to insert at the level of the broader collection as many “isothes:subGroup” properties as narrower collections of this collection.
Files containing “skos:Concept” or “rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#Concept’]]” are processed by this service.
This service allows the replacement of the identifiers (URI) of a SKOS/RDF-XML file by ARK identifiers built according to the recommendations of the California Digital Library (CDL).
An ARK identifier has the following syntax:
The transformation is performed in two stages:
1- Replacement of the resource URI (at the level of the concept scheme) by the following generic URI: http://my_site.fr/ark:/NAAN/ABC. The old URI is kept in a “dc:identifier” field.
At the concept level, an 8-character alphanumeric sequence followed by a dash and then a “check sum” completes this prefix and constitutes a unique ARK identifier for each concept of the resource.
| Prefix | Unique identifier |
| http://my_site.fr/ark:/NAAN/ABC | -CGT6ZZBQ-F |
2- URI recalculation for:
To generate ARK identifiers that comply with CDL recommendations (see details here), the generic URI must be replaced as follows:
Here is a real example: http://data.loterre.fr/ark:/67375/1WB
Note that in the absence of NAAN, the URI can not be considered an ARK identifier but can nevertheless be used without the ark:/NAAN/ part, the last part being a unique identifier.
Loterre offers various conversion modules.
This transformation allows to generate a SKOS file from a spreadsheet (Excel, OpenOffice, etc.) saved as CSV.
Loterre offers two variants of this service, depending on whether the field separator in the CSV file is a semicolon or a comma:
n.b.: with a CSV file whose separator is a semicolon use double quotation marks (” / quote) as text delimiter for fields that contain semicolons as ponctuation signs. Add quotation marks around such fields to avoid spliting of text at semicolon. If text contains quotes, they must be doubled.
The input file must:
| Terminological data | Label to use xx = 2 digit ISO code for language (*) |
Comment |
| Preferred label | prefLabel_xx | A “preflabel_en” is expected |
| Alternative label | altLabel_xx | |
| Hidden label | hiddenLabel_xx | |
| Definition | definition_xx | |
| Note | note_xx | |
| Scope note | scopeNote_xx | |
| Editorial note | editorialNote_xx | |
| History note | historyNote_xx | |
| Change note | changeNote_xx | |
| Example | example_xx | |
| Broader term | broader_xx | A “broader_en” is expected |
| Related term | related_xx | A “related_en” is expected |
| Group (collection) | group_xx | A “group_en” is expected |
| Exact match | exactMatch | |
| Close match | closeMatch | |
| Broad match | broadMatch | |
| Narrow match | narrowMatch | |
| Related match | relatedMatch |
(*) Replace “xx” by 2 digit ISO code for language; example “prefLabel_en” for the English preferred label. See list of ISO 639-1 codes.
The data is transformed as follows:
In addition, the transformation also inserts two blocks at the beginning of the SKOS/RDF-XML file:
– a “cc:License” block with the default Creative Commons CC-BY 4.0 license that should be changed if the resource is released under a different license.
– a “skos:ConceptScheme” block with:
If the concepts do not have identifiers, the default URI of the resource is “http: //www.mysite/vocabs/ABC”. It is also the root of the URI of concepts, relationships and possible collections. It must be replaced as follows:
At the concept level, the URI is a concatenation of the resource’s URI with a unique identifier; at the collection level, the URI is a concatenation of the resource’s URI with the group name by replacing the spaces with “_”.
To switch to ARK identifiers, use the transformation “Assign ARK identifiers to a valid SKOS/RDF-XML file”.
Files containing “skos:Concept” or “rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#Concept’]]” are processed by this service.
Loterre offers two variants of this service, depending of the field separator desired in the resulting CSV file:
The output file can be imported into a spreadsheet (Excel, LibreOffice, etc.) for editing (see the import procedure in Excel below).
The data are transformed as follows:
A first row “column headers” is created from the elements (skos or other properties) used to describe the different concepts of the SKOS/RDF-XML file:
Then, a line is generated for each concept of the file:
It should be noted that:
To import a CSV file to Excel:
The file modified in Excel and saved as CSV file can be transformed into SKOS using the service “Transform a semicolon-separated CSV file into a SKOS/RDF-XML file” or “Transform a comma-separated CSV file into a SKOS/RDF-XML file” depending on the type of separator used while saving the CSV file.
This transformation allows to generate an HTML file from a valid SKOS file. It processes files containing “skos:Concept” or “rdf:Description” of type “Concept”.
Two variants are proposed by Loterre, depending on the language version chosen:
The terminology entries are presented in the alphabetical order of preference (French or English):
The richness of the information displayed will depend on the content and structuring of the original SKOS file.
Transform a SKOS-XML into a PDF file
This transformation generates a PDF file from a valid SKOS file.
Two variants are proposed by Loterre, depending on the language version chosen for the resource:
Several sections are produced depending on the content and structure of the file:
Additional pages are inserted:
Note that the cover pages can be replaced by editing the final file with a PDF editor such as PDF Sam Basic.
The « Check » service permits an online chek of a SKOS terminology file validity.
It allows three types of checks to be performed: collections validity, concepts validity, concept scheme validity.
The color code of the detected anomalies indicates their degree of severity:
| red background | critical anomaly |
| orange background | major anomaly |
| yellow background | minor anomaly |
The service Controlling a SKOS/RDF-XML file at the collections level processes files containing “skos:Collection” or “rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#Collection’]]” or “rdf:Description[rdf:type[@rdf:resource=’http://purl.org/iso25964/skos-thes#ConceptGroup’]]”.
It performs a preliminary analysis of the resource to determine:
It then performs the checks and returns the results in the form of a table detailing the types of anomalies detected.
List of checks carried out:
| Code | Anomaly description |
|---|---|
| Col-0 | The resource contains neither skos:Collection, nor isothes:ConceptGroup, nor rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#Collection’]] or “rdf:Description[rdf:type[@rdf:resource=’http://purl.org/iso25964/skos-thes#ConceptGroup’]]” element. |
| Col-@0 | Missing URI identifier. A collection has no identifier. |
| Col-@N | Unauthorized attribute. Only the “rdf:about” attribute is authorized for “skos:Collection” or rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#Collection’]] or “rdf:Description[rdf:type[@rdf:resource=’http://purl.org/iso25964/skos-thes#ConceptGroup’]]” element. |
| Col-2 | Anomaly of structuration of collections. Despite the presence of an “isothes:superGroup” property in collections, no “isothes:subGroup” property was found in the corresponding super-collection. The menu “Insert narrower collections in a valid SKOS/RDF-XML file” can be used to fix the problem. |
| Col-3 | Inconsistency at the resource identifier level. The value of “rdf:resource” attribute on “skos:inScheme” element of a collection is different from the resource identifier (ConceptScheme). |
| Col-4 | Non-existent member. A member of a collection is not a concept of the resource. Create the corresponding concept or delete this member. |
| Col-5 | Collection identifier contains an unauthorized character (white space, apostrophe, double quotation mark, left bracket, right bracket). |
The service Controlling a SKOS/RDF-XML file at the concept level processes files containing “skos:Concept” or “rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#Concept’]]”.
It performs a preliminary analysis of the resource to determine:
It then performs the checks and returns the results in the form of a table detailing the types of anomalies detected.
List of checks carried out:
| Code | Anomaly description |
|---|---|
| D-Id | Uniqueness of the identifier (URI) of a given concept. Two different concepts can’t have the same identifier. |
| E-0 | Presence of an empty field (property). May interfere with the continuation of the control program. Can also prevent import into some terminology editors. |
| @-0 | Presence of an empty attribute. |
| R-A1 | Clash between semantic relations: the same concept is a related concept and a broader concept (direct or indirect) of the current concept. Cf. SKOS Reference (S27 Integrity Condition). |
| R-FX1 | Reflexive hierarchical relation: a concept is its own broader concept. |
| R-FX2 | Reflexive associative relation: a concept is its own related concept. |
| R-31 | Clash between associative and hierarchical relations: if concept A has concept B as a narrower concept and concept C as a related concept, then C can not be a narrower concept of B because concept C can not be linked simultaneously to concept A by two disjoint relationships “skos:narrowerTransitive” and “skos:related”. See details in SKOS-Primer and SKOS Reference. |
| R-32 | Clash between associative and hierarchical relations: if concept A has concept B as a broader concept and concept C as a related concept, then C can not be a broader concept of B because concept C can not be linked simultaneously to concept A by two disjoint relationships “skos:broaderTransitive” and “skos:related”. See details in SKOS-Primer. |
| R-B3 | Cycle between semantic relations: the same concept is a narrower concept and a broader concept of the current concept. |
| R-A2 | Clash between semantic relations: the same concept is a related concept and a narrower concept of the current concept. See SKOS Reference (S27 Integrity Condition). |
| R-NS | Non-symmetric associative link (skos:related). See SKOS Reference (Axiom S23); see Symmetry correction |
| R-0 | Relation (skos:related, skos:broader or skos:narrower) that targets a non-existent concept. |
| R-OR | Orphan concept: a concept that is not a top-concept, and which has neither broader nor narrower concepts. |
| CS-0 | Concept not linked to the concept scheme through “skos:inScheme” element. |
| CS-3 | Inconsistency at the level of the resource identifier (URI). The value of “rdf:resource” attribute in “skos:inScheme” element is different from the resource identifier. |
| LP-0 | Missing preferred label for one of the resource languages. |
| LP-N1 | More than one value preferred label per language tag. See SKOS Reference (S14 Integrity Condition) |
| LP-LA1 | Preferred label / alternative label duplicate within the same concept. See SKOS Reference (S13 Integrity Condition) |
| LP-LC1 | Preferred label / hidden label duplicate within the same concept. See SKOS Reference (S13 Integrity Condition) |
| LP-LP2 | Same preferred label for two different concepts. |
| LP-LA2 | Preferred label / alternative label duplicate between two different concepts. |
| LP-LC2 | Preferred label / hidden label duplicate between two different concepts. |
| LA-LA1 | Alternative label duplicate within the same concept. |
| LA-LA2 | Same alternative label for two different concepts. |
| LA-LC1 | Alternative label / hidden label duplicate within the same concept. See SKOS Reference (S13 Integrity Condition) |
| LA-LC2 | Alternative label / hidden label duplicate between two different concepts. |
| LC-LC1 | Hidden label duplicate within the same concept. |
| LC-LC2 | Same hidden label for two different concepts. |
The service Controlling a SKOS/RDF-XML file at the concept scheme level processes files containing “skos:ConceptScheme” or “rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#ConceptScheme’]]”.
It performs a preliminary analysis of the resource is performed to determine:
It then performs the checks and returns the results in the form of a table detailing the types of anomalies detected.
List of checks carried out:
| Code | Anomaly description |
|---|---|
| CS-N | Missing ConceptScheme element. The file contains neither a skos:ConceptScheme element nor a rdf:Description[rdf:type[@rdf:resource=’http://www.w3.org/2004/02/skos/core#ConceptScheme’]] element. The menu Insert a skos:ConceptScheme can be used to fix the problem. |
| CS-0 | Missing concept scheme identifier (URI). |
| CS-1 | Unauthorized attribute in ConceptScheme element. Only rdf:about attribute is authorized. |
| CS-2 | Missing skos:hasTopConcept properties. Despite a great structuration of the resource ConceptScheme element lacks skos:hasTopConcept properties to list top-concepts . The menu “Insert hasTopConcept properties” can be used to fix the problem. |
| CS-3 | Inconsistency at the level of the resource identifier (URI). The value of rdf:resource attribute in skos:inScheme element of a given concept is different from the resource identifier. |
The “Downlaod” service will allow you to download the full content of one of the resources stored in the Loterre triplestore, in a PDF, CSV, SKOS/XML or JSON-LD format.
From the Loterre platform, you can also:
One of your questions still remains unanswered? Ask it directly with the contact form.