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Providing context

Providing context. Controlled Vocabularies Roseanna Wright (with acknowledgements to Rob Thomas, ex. BODC). What is a vocabulary?. A person's vocabulary is the set of words within a language that are familiar to that person.

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Providing context

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  1. Providing context Controlled Vocabularies Roseanna Wright (with acknowledgements to Rob Thomas, ex. BODC)

  2. What is a vocabulary? • A person's vocabulary is the set of words within a language that are familiar to that person. • A vocabulary usually develops with age, and serves as a useful and fundamental tool for communication and acquiring knowledge. (R. Thomas, BODC, September 2016)

  3. Why use controlled vocabs? Divided by a common language (R. Thomas, BODC, September 2016)

  4. Why use controlled vocabs? Support terms with explicit definitions Remove ambiguity Resource for all Publish on the web Make the implicit become explicit! (R. Thomas, BODC, September 2016)

  5. MEDIN & Controlled Vocabs Where do MEDIN use controlled vocabs? • Discovery Metadata Standard • Categories of data (keywords), geographic coverage, formats of data files (amongst others) • Data Guidelines • Categories and models of instruments, organisations, quality control flags, unambiguous vessel identification codes for survey vessels (amongst others)

  6. Vocabularies used by MEDIN http://www.epsg.org/ http://www.marinespecies.org/msbias/index.php http://www.ices.dk/datacentre/reco/

  7. Availability through website www. medin. org.uk

  8. NVS2 Vocabulary client https://www.bodc.ac.uk/data/codes_and_formats/vocabulary_search/ • Instruments, platforms, sea areas, geometries etc

  9. Vocabs to aid context (demo) 1 What can become less ambiguous with help of vocabs? • Vocabs will give clarity on: • Ship reference code (C17 list in NVS2) • Instrument type (L22 list in NVS2) • Unit codes (P06 in NVS2) • Parameter codes (P01 in NVS2)

  10. Vocabs to aid context (demo) 2

  11. MEDIN Keywords • Useful discovery metadata includes descriptions of the categories of data measured • MEDIN recommends “SeaDataNet Parameter Discovery Vocabulary” – P02 • Accessible via BODC and SeaDataNet • Two main routes • Access table P02 directly from MEDIN website (BODC and SeaDataNet clients) • Use SeaDataNethierarchical view to P02 Demonstration

  12. Things to be aware of… • Searching may not be intuitive – definitions may have text in different orders to what is expected e.g. sea temperature as ‘Temperature of the water column’ not ‘Water column temperature’ • Vocabs are no use if not correctly referenced…what is best practice? URIs, term codes, vocabulary full titles, dates etc. • Different vocabs may have similar terms but different use cases. Research which is the right one for your needs. • Unusual terminology

  13. How to add? E-mail Sean Gaffney sgaf@bodc.ac.uk or Roseanna Wright roswri@bodc.ac.uk - MEDIN will check with appropriate governance group.

  14. Providing context - Coordinate Reference Systems The data were sampled at 252 345.9, 204 301.6 The data came from an area 6 miles from the lighthouse, bearing 245 degrees • Data cost money to sample. • Without knowing where and when a measurement or observation occurs they have no value. • Need therefore to be able to provide a trustworthy unambiguous position for samples. • Are the following numbers enough to provide precise positions of sampled data? The data are from 54 degrees 10’ 45’’ North, 3 degrees 30’ 20’’ West None of these are satisfactory!

  15. Coordinate Reference Systems LATITUDE and LONGITUDE are NOT UNIQUE! Coordinates define a position unambiguously only when the reference system that those coordinates are part of has been identified!

  16. Coordinate Reference Systems • What is a CRS? • This is a coordinate system which is referenced to the earth based on a datum. OGP, 2007, Surveying and Positioning Guidance note 1

  17. Coordinate Reference Systems I need help! Where’s Big Ben? I’m going to survey it so need its coordinates! That’s easy  My GPS says it’s 51◦ 30’ 2.647” N, 0 ◦ 7’ 28.654”W I’m confused! You can’t both be right…or can you? That’s odd  My GPS is different. It says 51◦ 30’ 5.53” N, 0 ◦ 7’ 28.654”W

  18. Coordinate Reference Systems Big Ben (ref. https://twcc.fr/en/#)

  19. Implications! • Platform drilling . Meridional grid wrongly applied in directional software. 12 dry wells dug. Loss of capital expenditure of $2 million. Reputation damage. New program of work needed • Construction. Proposed position for new subsea manifold issued on ED50 datum. Contractor assumed positions in WGS-84 and drilled in wrong place. Resulted in fine of $500,000, reputational damage and contract dispute between contract parties

  20. Practice Aim – to familiarise yourself with different controlled vocabularies Read through the accompanying handout ‘MEDIN Workshops controlled vocabulary practical exercise’ Work through the sheet, trying to answer questions 1-5. If you succeed in answering all 5 questions, try and move on to question 6. Resources to help with this exercise are all available at http://www.medin.org.uk/marine_data_standards/controlled_vocabs.html Don’t hesitate to ask for help. If you wish to work in groups, please do so 

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