In the Japan Search RDF Schema, temporal, spatial, and agential information (information related to where, when, and how) in metadata aggregated from participating institutions is converted into normalized expressions as much as possible.
This normalization process involves defining the metadata value and converting it into a URI* representation.
In the normalization process, information is divided into elements that can be restructured, identified, and linked to data from external hubs of Linked Open Data. One example of such a hub is the Web NDL Authorities, from which authority data created by the NDL can be acquired.
Wikidata is another example, where URIs connect to other data on the web. This process enables us to broaden utilization of data.
* In the strictest sense, the term Internationalized Resource Identifier (IRI) should be used here, since non-ASCII characters may be used. However, the term URI is used here for convenience.
1. Normalization of temporal information
1-1. URIs for temporal information
In normalizing temporal information, a certain range of time is defined as an entity, taking the calendar year as a minimum unit. A unique URI is given to the time span within the namespace: https://jpsearch.go.jp/entity/time/.
Example 2: https://jpsearch.go.jp/entity/time/室町時代 (A time entity covering the time period commonly referred to as the Muromachi period in Japanese history)
1-2. Temporal information structure
Information related to time is structured with multiple elements, such as Japanese calendar names, starting or ending dates of an historical era, or other values.
The following properties, jps:value and jps:era, have structured temporal information value.
This property describes a particular time range, such as a single year, a time span, a century, or an era. It is normalized with the year as the smallest unit and is refined by using the following sub-properties. The number in the square brackets [] indicates the number of occurrences within a single jps:value property.
rdf:type
Indicates that the jps:value property in the structured property represents a time range and is input as either type:Time or type:HistoricalEra (if the value is an era name). ([1])
rdfs:label
Indicates the name of the relevant time range. (Literal [1])
schema:name
Indicates variants of the name of the relevant time range. Language tags are used to identify transcriptions in Japanese characters and other languages. (Literal [1-n])
schema:startDate
Indicates the starting year of the time range. (xsd:gYear type [1])
schema:endDate
Indicates the ending year of the time range. If the time range is a single year, this value is identical to schema:startDate. (xsd:gYear type [1])
jps:start
Indicates the starting year of the time range (schema:startDate)as an integer. (xsd:integer type [1])
jps:end
Indicates the ending year of the time range (schema:endDate as an integer. (xsd:integer type [1])
jps:startEntity
Consists of a link to an entity describing the starting year when the described time range is longer than a year. (URI [0-1])
jps:endEntity
Consists of a link to an entity describing the ending year when the described time range is longer than a year. (URI [0-1])
skos:closeMatch
Consists of a link to the closest time range by calendar year when the described time range is an era.
This sub-property is used when the time range is not definite, such as when there are different names to the time range, when the time range is in the ancient time period, when there are different opinions to the time span, or when the time range cannot be counted by years. (URI [0-1])
owl:sameAs
Consists of a link to open data of the time range with the same definition as in Japan Search. (URI [0-n])
This property describes an era. It is normalized and refined by using the following sub-properties. The number in the square brackets [] indicates the number of occurrences within a single jps:era property.
rdf:type
Indicates that the jps:era property represents an era, with the value always type:HistoricalEra, a subclass of type:Time. ([1])
rdfs:label
Indicates the name of the relevant era. (Literal [1])
schema:name
Indicates variants of names of the era. Language tags are used to identify transcriptions in Japanese characters and other languages. (Literal [1-n])
schema:startDate
Indicates the year the era started. (xsd:gYear type [1])
schema:endDate
Indicates the year the era ended. In the case the era was a single year, the value would be the same as schema:startDate. (xsd:gYear type [1])
jps:start
Indicates the year the era started (schema:startDate) as an integer. (xsd:integer type [1])
jps:end
Indicates the year the era ended (schema:endDate) as an integer. (xsd:integer type [1])
jps:startEntity
Consists of a link to an entity representing the first year of the era. (URI [0-1])
jps:endEntity
Consists of a link to an entity representing the last year of the era. (URI [0-1])
rdfs:isDefinedBy
Consists of the namespace which defines the time range URI in Japan Search: https://jpsearch.go.jp/entity/time/, indicating that the corresponding era is uniquely defined within this namespace. ([1])
skos:closeMatch
Consists of a link to the closest time range by calendar year.
This sub-property is used when the time range is not definite, such as when there are different names to the time range, when the time range belongs to an ancient period, when there are different opinions to the time span, or when the time range cannot be counted by years. (URI [0-1])
owl:sameAs
Consists of a link to open data of the time range with the same definition as in Japan Search. (URI [0-n])
Range
type:HistoricalEra
Data Type
URI defined by time ontology
Occurrence
A resource may have 0 or many properties, and each jps:temporal has 1.
2. Normalization of spatial information
2-1. URIs for spatial information
In normalizing spatial information, a certain extent of space is defined as an entity at the country, prefecture, city and county levels. A unique URI is given to the place within the namespace https://jpsearch.go.jp/entity/place/ .
Information related to space is structured with multiple elements, such as name, latitude and longitude, or municipal code. The following properties, jps:value and jps:region, have structured spatial information value.
This property describes information on places. It is normalized at the country or prefecture level, and is refined by using the following sub-properties. The number in the square brackets [] indicates the number of occurrences within a single jps:value property.
rdf:type
Indicates that the jps:value property in the structured property represents a place, and is input as either type:Place or type:Country (if the value is a country). ([1])
rdfs:label
Indicates the name of the relevant place. (Literal [1])
schema:name
Indicates variant names of the place. Language tags are used to identify transcriptions in Japanese characters and other languages. (Literal [1-n])
schema:geo
Consists of the URI of geohash.org for the spatial information corresponding to the normalized value. (URI [0-n])
schema:geoCoveredBy
Consists of the geohash URI that indicates the mesh containing the described place. The number of digits corresponds to the target granularity. There are three digits for prefectures, four digits for cities and municipalities, and six digits for blocks. (URI [0-1])
schema:isPartOf
Consists of the spatial information for the larger area that the relevant place is part of. (URI [0-n])
rdfs:isDefinedBy
Consists of the namespace which defines the spatial range URI in Japan Search when the described place is normalized: https://jpsearch.go.jp/entity/place/. Indicates that the corresponding place is uniquely defined within this namespace. ([0-1])
rdfs:seeAlso
Consists of links to the agential entity and to open data of the same entity when the organization or corporation, such as a municipality, corresponding to the relevant place is normalized in Japan Search. (URI [0-n])
Range
time:Place, type:Country
Data Type
URI normalized at the country or prefecture level (the same value as schema:spatial)
Occurrence
A resource may have 0 or many properties, and each jps:spatial has 1.
This property describes information on places normalized at the city or county level.
rdf:type
Indicates that the jps:region property in the structured property represents a place, and the value is always type:Place. ([1])
rdfs:label
Indicates the name of the relevant place. (Literal [1])
schema:name
Indicates variant names of the place. Language tags are used to identify transcriptions in Japanese characters and other languages. (Literal [1-n])
schema:geo
Consists of the URI of geohash.org for the spatial information corresponding to the normalized value. (URI [0-n])
schema:description
Consists of a description of the relevant place. (Literal [0-n])
schema:geoCoveredBy
Consists of the geohash URI that indicates the mesh containing the relevant place.
The number of digits corresponds to the target granularity. Three digits for prefectures, four digits for cities and municipalities, and six digits for block level. (URI [0-1])
schema:isPartOf
Consists of the spatial information for the larger area that the relevant place is part of. (URI [0-n])
rdfs:isDefinedBy
Consists of the namespace which defines the spatial range URI in Japan Search when the described place is normalized: https://jpsearch.go.jp/entity/place/. Indicates that the corresponding place is uniquely defined within this namespace. ([0-1])
rdfs:seeAlso
Consists of links to the entity and to open data of the same entity when there is an organization or corporation, such as a municipality, corresponding to the relevant place. (URI [0-n])
Range
type:Place
Data Type
URI (URI normalized at the city or county level)
Occurrence
A resource may have 0 or many properties, and each jps:spatial has 1.
3. Normalization of agential information
3-1. URIs for agential information
In normalizing agential information, contributors to the creation of content or people and organizations which have become the subject of content, are defined as entities. A unique URI is given to the person or organization within the namespace https://jpsearch.go.jp/entity/chname/.
This property describes information on people or organizations. It is refined by using the following sub-properties. The number in the square brackets [] indicates the number of occurrences within a single jps:value property
This property describes information on people or organizations. It is refined by using the following sub-properties. The number in the square brackets [] indicates the number of occurrences within a single jps:value property.
rdf:type
Indicates that the jps:value property in the structured property represents a person or organization that either has to do with or is the subject of the content, and is input as either type:Agent or type:Person (if the value is a person). ([1])
rdfs:label
Indicates the name of the relevant person or organization. (Literal [1])
schema:name
Indicates variant names of the person or organization. Language tags are used to identify transcriptions in Japanese characters and other languages (Literal [1-n])
rdfs:isDefinedBy
Consists of the namespace which defines the URIs of people and organizations in Japan Search when the described person or organization is normalized: https://jpsearch.go.jp/entity/chname/. Indicates that the corresponding person or organization is uniquely defined within this namespace. ([0-1])
owl:sameAs
Indicates that the relevant person or organization is the same as the information of the linked person or organization (provided as open data). (URI [0-n])
schema:description
Describes the relevant person or organization. (Literal [0-n])
schema:image
Consists of the URI of the image or photo related to the relevant person or organization. (URI [0-n])
schema:location
Consists of the URI of the spatial information when the value of rdfs:label is an entity which has information on its location such as museums. (URI [0-n])
Range
type:Agent, type:Person
Data Type
URI (name authority URI in source data or URI normalized by Japan search) (matches the value of schema:agential),
Name authority URI from the source data or URI normalized in Japan Search (the same value as schema:agential)
Occurrence
A resource may have 0 or many properties, and each jps:agential has 1.