some problems with standard geospatial metadata...simon cox, bruce simons, nick car 12 march 2015...

Simon Cox, Bruce Simons, Nick Car

12 March 2015

LAND AND WATER FLAGSHIP

Some problems with standard geospatial metadata

This presentation

• Asks some questions

• Does not provide all the answers • … but suggests some directions …

Presenter name | Presenter title

31 January 2012

ADD BUSINESS UNIT/FLAGSHIP NAME

Problems with metadata | Nick Car 2 |

Outline

• ANZLIC and GeoNetwork

• Where did ANZLIC come from?

• Records

• Uses of metadata

• UML vs XML

• RDF

• RDF vocabularies


31 January 2012



ANZLIC Metadata


31 January 2012



Where did ANZLIC come from?

● ANZLIC a profile of ISO

19115:2003

5 |



19115:2003

● ISO 19115 designed by a

committee

6 |



19115:2003


committee

7 |

(horse designed by committee =

camel)



19115:2003


committee

○ US FGDC metadata a

strong precedent

○ requirements collected in

the 1990s

○ image and map librarians

8 |


camel)



19115:2003


committee

○ US FGDC metadata a

strong precedent

○ requirements collected in

the 1990s

○ image and map librarians

9 |


camel)

> dawn of the internet, dataset == file

> 10,000s datasets in standard series,

metadata == digital ‘index cards’

Problem #1: Data ≠ Datasets?

• When cataloguing books, maps, images, even files, the card-index metaphor is OK • A discrete record for each item of data

• Now we expect to access data at a variety of granularities, the dataset/metadata record paradigm no longer applies

• It is a sea of data, and should be matched by a sea of metadata (maybe in the same place)


Breaking it down

• Structural decomposition


• Functional decomposition

Lawrence, Lowry, Miller, Snaith & Woolf, Information in environmental data grids. Phil. Trans. A, 2009

Problem #2: One record can’t serve all purposes

• But one ‘record’ is all you got!


ISO metadata was formalized as UML classes


GeoNetwork stores metadata as XML documents in a text database (Lucene)


Problem #3: Documents package text, not objects

• Instances of UML classes = Objects

• XML document = serialization for transport

• Treating the XML document as ‘canonical’ makes a basic category error: ➢XML validation ≠ quality control

➢if you only intend to manage it as text, why bother with a UML analysis?

For object-oriented behavior, the serialized form must be ‘un-marshalled’ for processing


Metadata creation


Problem #4: Index cards are not infrastructure

• Metadata-entry paradigm encourages record counting as a KPI

• Surely there are better measures of usefulness?

• How can we know, if it is not part of a joined-up architecture


What does everyone else do?

1. Specialist systems for specialized communities – Is spatial special? Do we want our spatial data in the mainstream?

2. Don’t bother with metadata, just index the content – The original strategy of the search engines

– Google Knowledge Graph now works with entities, not text

– (shame the entities don’t have persistent URIs …)

3. Metadata annotations – schema.org – semantic-web-lite

4. What about the Data Repositories?


Research Data Repositories

• Still a lot of variation • RIF-CS

• MARC

• Dublin Core

• Data Catalog Vocabulary (DCAT)




• MARC

• Dublin Core





• MARC

• Dublin Core


• RDF vocabularies? • DC, DCAT

• FOAF, PROV-O, VoID, SKOS, ADMS, LOCN


INSPIRE profile of DCAT-AP


INSPIRE metadata record as RDF


RDF benefits

• Standard vocabularies used in the broader community

• Intrinsically object/resource oriented

• URIs for keys - linked data

• Open world – missing information doesn’t make it invalid

• No intrinsic granularity


Summary

ANZLIC + GeoNetwork:

☹ Record-oriented metadata doesn’t match granularity of data

☹ Each record must serve multiple functions

☹ Object oriented design, but serialization-oriented processing

☹ Incentive to create records, not architecture

☹ Not aligned with anyone else’s metadata

RDF?:

☺ Graph of metadata to match graph of data

☺ Targeted metadata subsets can be constructed using SPARQL

☺ Intrinsically resource-oriented

☺ Part of web of Linked Data

☺ Standard RDF vocabularies


LAND AND WATER FLAGSHIP

Thank you Land and Water Flagship Nick Car Research Engineer

t +61 7 3833 5600 e [email protected]

Land and Water Flagship Simon Cox Research Scientist

t +61 3 9252 6342 e [email protected] w people.csiro.au/C/S/Simon-Cox