Description
From: http://joinup.ec.europa.eu/mailman/archives/dcat_application_profile/2015-February/000123.html
For specifying update frequency (dct:accrualPeriodicity), DCAT-AP recommends the use of the code list defined in the Dublin Core Collection Description Frequency Vocabulary
The DCAT W3C Recommendation, however, uses in one of the examples another code list, derived from SDMX, and recommended in the W3C DataCube vocabulary
Proposed solution
Choose between DCMI and SDMX frequency vocabulary
Component
CodeCategory
improvement
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Comments
Shall we look into this in the context of the StatDCAT-AP work?
There is also a MDR table http://publications.office.eu/resource/authority/frequency with the DCMI code, plus some additionnal codes, in a multilingual version.
I looked at both the DCMI list and the SDMX list and it appears that the DCMI list is more complete -- it is a collection of 17 terms (http://dublincore.org/groups/collections/frequency/) while SDMX list has 8 (https://raw.githubusercontent.com/UKGovLD/publishing-statistical-data/master/specs/src/main/vocab/sdmx-code.ttl#), although not all of these 8 appear in the DCMI list. I can't compare them to the MDR table becasue that is not online.
Given that the three lists mentioned are all slightly different, it's going to be hard to decide between them. One point that I think we need to consider is: is there really a pressing reason, on the practical level, to consider changing the current list. For example, are there datasets that absolutely need a term that is not in the DCMI list?
We need to carefully consider this, because changing a mandatory controlled vocabulary means that all implementations that make use of the 'old' list will immediately become non-compliant and all data that uses the old list will need to be converted. An expensive operation that we may want to avoid unless there is a really good reason to do make the change.
Makx, all,
This is just to point out that this issue is relevant also to GeoDCAT-AP. In ISO 19115 / 19139, "maintenance information" is expressed by using a code list, that can be partially mapped to the DC Frequency vocabulary.
The new draft of the GeoDCAT-AP specification includes a mapping table. I add it below, including the mutual mappings with the SDMX code list.
I wonder whether an option would be to support an "integrated" list, using as primary vocabulary the DC one (which is the richest, as you say), plus the missing frequency codes from ISO 19115 and SDMX. The problem is that we don't have (yet) URIs for the ISO one.
Probably, the OP's Frequencies authority table mentioned by Jean, and currently under preparation, may offer a comprehensive solution.
ISO 19115 - MD_MaintenanceFrequencyCode
SDMX
Dublin Core Collection Description Frequency Vocabulary
continual
N (minutely)
continuous
daily
D (daily)
daily
weekly
W (weekly)
weekly
fortnightly
biweekly
monthly
M (monthly)
monthly
quarterly
Q (quarterly)
quarterly
biannually
S (half-yearly, semester)
semiannual
annually
A (annual)
annual
asNeeded
irregular
irregular
notPlanned
unknown
PS: Table revised on 21/04/2015 based on Madeleine's comment.
The Frequency authority table contains all codes from the Dublin Core Frequency vocabulary + the following additional codes:
We have added a same as relationship to the DC frequency vocabulary.
The table contains labels in all official EU languages.
We could expand it by adding the codes from ISO 19115 and SDMX that are not covered by DC Frequency and add mappings to the rest of the codes.
As with all authority tables, if there is a need to add an additional code, it can be requested and we can issue a new version.
Hello,
I wonder if the "biannually" is correctly aligned with "biennal".
Regarding ISO 19115 the frequencies are presented in a logic order :
continual, daily, weekly, fortnightly, monthly, quarterly, biannually, annually, etc.
Could you please check if "biannually" should not be aligned with "semiannual"?
In order not to confuse these close words, the prefix "bi-" is generally used for lasting periods of time (every two, three ...), whereas the prefix "semi-" is used for every periods of time (every week / month / year).
See also usage note "Some authorities report confusion between biennially and biannually. Using "semiannually" may reduce the risk of confusion." http://en.wiktionary.org/wiki/biannually
http://en.wiktionary.org/wiki/fortnightly
Thanks.
Hello,
I wonder if the "biannually" is correctly aligned with "biennal".
Regarding ISO 19115 the frequencies are presented in a logic order :
continual, daily, weekly, fortnightly, monthly, quarterly, biannually, annually, etc.
Could you please check if "biannually" should not be aligned with "semiannual"?
In order not to confuse these close words, the prefix "bi-" is generally used for lasting periods of time (every two, three ...), whereas the prefix "semi-" is used for every periods of time (every week / month / year).
See also usage note "Some authorities report confusion between biennially and biannually. Using "semiannually" may reduce the risk of confusion." http://en.wiktionary.org/wiki/biannually
http://en.wiktionary.org/wiki/fortnightly
Thanks.
You're right, Madeleine. Thanks for spotting my typo.
Here's the definition of "biannually" in the ISO code list:
data is updated twice each year
So, as you say, this corresponds to "semiannual" in the DC code list.
The Dublin Core Collection Description Frequency Vocabulary is fine. It has a reasonable granularity and contains the specials: "continous" and "irregular". It covers all frequently used frequences. Exceptions can easily be matched to the closest value.
If the MDR table of the EU-Publications office is matched with the DC list it has the advantage that it is multi-ligual, but the link Jean provided (http://publications.office.eu/resource/authority/frequency) is dead and on the MDR page about NAL's the NAL for Frequncies is "Under preparation".
The Frequency authority table will be published on Wednesday the 10th of June. It contains for the moment the following concepts:
ANNUAL: annual
ANNUAL_2: semiannual
ANNUAL_3: three times a year
BIENNIAL: biennial
BIMONTHLY: bimonthly
BIWEEKLY: biweekly
CONT: continuous
DAILY: daily
DAILY_2: twice a day
IRREG: irregular
MONTHLY: monthly
MONTHLY_2: semimonthly
MONTHLY_3: three times a month
OTHER: other
QUARTERLY: quarterly
TRIENNIAL: triennial
UNKNOWN">unknown</LIBELLE>
UPDATE_CONT">continuously updated</LIBELLE>
WEEKLY">weekly</LIBELLE>
WEEKLY_2">semiweekly</LIBELLE>
WEEKLY_3">three times a week</LIBELLE>
Attached the SKOS version of the table as it will be published. The RDF file is in a zip file, because otherwise it could not be uploaded to Joinup.
It contains a SKOS exact match with the DC code list and contains labels in all official EU languages.
The advantage of the table is in my opinion that it is maintained by the Publications Office of the EU, that it contains labels in all EU languages and that new concepts can be added (quickly) if needed.
The URI for this table is the following: http://publications.europa.eu/resource/authority/frequency
The Working Group diceded to mandate the use of the Frequencies NAL, URI http://publications.europa.eu/mdr/authority/frequency/. This has been included in section 5.2 in the draft of the DCAT-AP revision.