Metadata of geographic information

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1 Metadata of geographic information Kai Koistinen Management of environmental data and information

2 Topics Metadata of geographic information What is metadata? Metadata standards and recommendations Metadata requirements of INSPIRE Spatial data quality Quality standards and recommendations

3 Metadata Metadata is data about data. Answers to questions What How Where What What kind of Whose Who Etc Metadata can describe Single features Datasets Collection of datasets = Dataset series Services that are used to delivere the data

4 Metadata With metadata you can for example Categorize data Search for data Find how the data should/could be used Find the contact that is responsible for the data Evaluate the quality of the data Find a way to get the data Find the spatial and temporal extent of the data

5 Metadata Use Producing Delivery Search Data producing User needs Data quality Data structures and organization Data search Identify the data Find the data Evaluate the fit for purpose Data delivery How to get the data Costs of data and delivery Data use Evaluate results User needs

6 Standardization International geographic informtation standardization committee ISO/TC211 ( Many geographic information standards (191xx series) Commercial OGC (Open Geospatial Consortium) ( Standards, specifications, best practices Everything available free of charge National JHS recommendation system ( National recommendations mainly for public administration Everything available free of charge

7 Metadata standars - why? Harmonized way to describe datasets Easy to compare Metadata can be delivered from service to service Better usability For example search applications are easier to implement International interoperability When you know the standard you know the structure of all metadata

8 Metadata standars: ISO 19115:2003 Geographic Information Metadata International ISO-standard on geographic information metadata Works as a basis for other metadata standards and profiles Defines a structure for describing digital geographic information Standard defines: Metadata elements Metadata schema Metadata terms, concepts and definitions and extension procedures Standard was updated in 2014 but the new version has not been taken into use for example in INSPIRE

9 ISO 19115: elements 1. Metadata identification 2. Resource identification 3. Content information 4. Schema information 5. Spatial representation info 6. Reference system info 7. Quality information 8. Portrayal 9. Restrictions 10. Distribution 11. Maintenance 12. Extent 13. Contact and responsible parties

10 Other ISO metadata standards ISO Metadata XML encoding Based on ISO structure Metadata encoding, validation and distribution htm?csnumber=67253 Included in the new ISO 19115:2014 standard ISO high-level standard that describes service architectural patterns, presents a taxonomy for geographic services, and provides guidelines for the selection of services includes service metadata definition htm?csnumber=59221

11 OGC s CSW standard CSW (Catalog Service for the Web) defines common interfaces to discover, browse, query and managing metadata Standard CSW interface should support following operations GetCapabilities DescribeRecord GetRecords GetRecordById GetDomain Harvest Transaction

12 JHS 158: Paikkatiedon metatiedot JHS recommendation on geographic information metadata UML diagrams Metadata elements Code lists INSPIRE metadata profile Based on ISO 19115:2003 standard Will be updated in 2017 (changes mainly to INSPIRE annex)

13 INSPIRE SDI Applications and portals Service layer Data layer

14 INSPIRE and metadata Public administration bodies are obliged to create metadata on their INSPIRE datasets and services Dataset and service metadata must be available in national discovery service Discovery service must have CSW API implemented In Finland Paikkatietohakemisto is the national INSPIRE discovery service Requirements are defined in EU commission regulation 1205/2008 Techical guidelines for implementing the metadata in Metadata Technical Guidelines document Based on ISO and ISO See also JHS 158 Paikkatiedon metatiedot Inspire-metadata in annexes 4 and 5

15 Deadlines Dataset metadata Annexes I and II: by Annex III: by View services Annexes I and II: by Annex III: by Download services Annex I and II: by Annex III: by

16 Metatiedot INSPIREssä Identification Classification Keywords Spatial extent Temporal reference Quality Conformity Conditions for access and use Responsible organizations Metadata on metadata

17 Metadata maintenance National implementation options for INSPIRE metadata maintenance Paikkatietohakemisto metadata editor Own metadata editor and XML import in Paikkatietohakemisto Own discovery service with CSW API. Metadata harvested to Paikkatietohakemisto automatically via CSW API

18 Spatial data quality Kai Koistinen Management of environmental data and information

19 Examples on spatial data quality Red polygon national field register (Peltolohkore kisteri) Yellow filled polygon topographi c database (Maastotiet okanta)

20 Examples on spatial data quality Building in Topographi c DB but not in Population register Building in population register but not in topodb

21 What is quality of spatial data? Previous examples were randomly selected to describe situations where quality information of spatial data could be important for the user. In previous examples user needs quality information for example to evaluate which dataset is more likely to be up to date and correct

22 Why spatial data quality management is needed A central requirement in data harmonization and interoperability is that the quality of data has been measured and documented in common way Better management of quality is needed especially when different organizations are responsible for producing the data Main issues Quality measurement Quality evaluation Quality reporting

23 Quality management framework Kuva: JHS 160

24 Spatial data quality: standards and recommendations ISO 19157:2013 (Geographic information Data quality) Replaces ISO 19113, and standards ISO 19158:2012 (Geographic information - Quality assurance of data supply) Capability of data producers for delivering required quality JHS 160 ( Based on ISO standards (19113, 19114, 19138) Metadata standards and recommendations give guidance on quality reporting in metadata INSPIRE technical guidelines present some requirements regarding quality Vocabulary of Geoinformatics (Geoinformatiikan sanasto) chapter 5: Paikkatiedon laatu Based on ISO More common ISO quality standards (ISO 9000 series)

25 Data quality evaluation (JHS 160) Quality evaluation is comparison of produced quality to required quality level Quality assessment procedure 1. Define data quality scope 2. Identify applicable data quality elements and subelements for the evaluated data 3. Identify data quality measure for the data quality element 4. Choose quality evaluation method 5. Solve data quality results 6. Report the quality result in metadata and/or as a quality report

26 1. Quality scope Define the data that will be examined (for example dataset or its subset) Spatial data quality is typically spatially heterogenic = quality is dependent on location -> divide the dataset into homogenous subsets to get reliable results

27 2. Quality elements and subelements Completeness: Commission / Omission Logical consistency: Conceptual consistency / Domain consistency / Format consistency / Topological consistency Positional accuracy: Absolute accuracy / Relative accuracy Temporal quality Katso myös

28 3. Quality measure Clearly defined quality measures are needed for comparing the quality of two or more datasets ISO standard defines some measures for each quality elements (also available in JHS 160 annex II) For positional accuracy for example measures Number of values greater than defined positional difference, Covariance matrix etc

29 4. Evaluation method Dataset conformance evaluation must be based on comparison to some reference Direct evaluation method: internal or external data reference Indirect evaluation method: evaluation based on expert knowledge Based on JHS160 using indirect methods should be avoided

30 5. Quality result Output of evaluation method is called quality Quality result can be Quantitative result Conformance result Descriptive result

31 6. Reporting Measured quality should always be reported in dataset metadata Separate quality report should be used when additional information is needed For example when metadata contains only the conformity result but not the details of the conformity evaluation

The European Commission s science and knowledge service. Joint Research Centre

The European Commission s science and knowledge service Joint Research Centre GeoDCAT-AP The story so far Andrea Perego, Antonio Rotundo, Lieven Raes GeoDCAT-AP Webinar 6 June 2018 What is GeoDCAT-AP Geospatial