1. Controlled Vocabularies
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

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

8. NVS2 Vocabulary client
Instruments, platforms, sea areas, geometries etc

10. Vocabs to aid context (demo) 1
Demonstration file 1 for ICIT workshop
Date
12/10/2017
Time
12:00
Sample location
Off Stromness to Scrabster ferry, docked in Stromness
Instrument
Seabird CTD
Units
deg
kg/m3
ug/l db
temp
sal
dens
chl
dep
26.899
8.23
0.54
26.976
8.12
1.03
26.798
7.98
1.56
26.888
7.99
2.1
26.453
7.87
2.59
26.789
8.02
3.01
26.761
3.54
26.784
8.03
4.02
26.654 8
4.54 36
26.865
5.01
5.51
26.666
7.65
6.01
25.998
7.92
6.52
27.001
7.04
26.973
7.59
26.884
8.11
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)

11. Vocabs to aid context (demo) 2
Time
12:00
Sample location
Off docked in Stromness
Instrument
Seabird CTD
Units
deg
kg/m3
ug/l db
temp
sal
dens
chl
dep
26.899
8.23
0.54
26.976
8.12
1.03
26.798
7.98
1.56
26.888
7.99
2.1
26.453
7.87
2.59

12. 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 SeaDataNet hierarchical view to P02
Demonstration

13. 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

14. How to add?
Sean Gaffney or Roseanna Wright
- MEDIN will check with appropriate governance group.

15. None of these are satisfactory!
Providing context - Coordinate
Reference Systems
The data were sampled at ,
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!

16. 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!

17. 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

18. 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’ ”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’ ”W

19. Coordinate Reference Systems
Big Ben (ref.

20. 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

21. 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 Don’t hesitate to ask for help. If you wish to work in groups, please do so 