1. Intuitive, OGC conformant search for spatial and non-spatial data in a web-based information system > Malte Ahrens > 2013-04-22 Intuitive, OGC-Conformant Search for Spatial and Non-Spatial Data in a Web-Based Information

2. Folie 2 Slide 2 Content The context: WISDOM - Water-related Information System for the sustainable Development of the Mekong Delta, Vietnam Metadata: What it looks like Data search in WISDOM Data search and Metadata Outlook

3. Folie 3 WISDOM System Slide 3 http://wisdom.eoc.dlr.de/Elvis

4. Folie 4 WISDOM System: Content in terms of topics Climate Change and Vulnerability Analyses Climate Change and Vulnerability Analyses Analyses of Legal System Analyses of Legal System Training, CB Institutional Mapping Institutional Mapping Landuse Change Slide 4 Water quantity, demand, reliability Water quantity, demand, reliability Socio Economic Changes Basin characteristics EO based Monitoring Basin characteristics EO based Monitoring Water Quality, Pollution

5. Folie 5 Slide 5 Statistical data Statistical data PDF documents in-situ sensor observations in-situ sensor observations Raster data Vector data WISDOM System: Content in terms of data types

6. Folie 6 WISDOM System: Wrap up Vast amount of data Different data types in one system Different semantics of data How to find appropriate data within the information system?  We use OGC compliant metadata to describe every dataset, be it geographic or not! Slide 6

7. Folie 7 Slide 7 Need for Metadata: OGC The Open Geospatial Consortium (OGC) is an international standardization organization Definition of standards for geospatial content and services, GIS data processing and data sharing  Catalogue Service for the Web (CSW) as interface description that uses ISO 19139 to make metadata accessible on the World Wide Web

8. Folie 8 Slide 8 Need for Metadata: what is the content of metadata? Which region does it cover? Whichprojection? Who is the point of contact? Which time does it cover? Who provided the metadata? How was it produced? What about quality? Which topic? ?  Metadata provide answers to these questions!

9. Folie 9 Slide 9 Need for Metadata: how does metadata look like? ISO 19115:2003 and ISO 19139: The standards for metadata descriptions of geodata content for metadata The metadata are structured as XML

10. Folie 10 Need for Metadata: WISDOM Profile Discussion in project, what information is needed as Metadata Definition of thesaurus to categorize data, such as Infrastructure, Hydrology  Lengthy process to agree upon shared vocabulary! We all needed to speak the same language Slide 10

11. Folie 11 Slide 11 data Need for Metadata: Search in WISDOM CSW WMS Meta- data Meta- data Meta- data describe Search for Data XML

12. Folie 12 Data search in WISDOM: how does it look like? No freetext search to avoid frustration: homonyms, synonyms etc Search data by applying filter  Time  Topic  Region  Datatype Search data by applying filter Verena Klinger Slide 12

13. Folie 13 Data search in WISDOM: Example Slide 13

14. Folie 14 Data search in WISDOM: Example (ctd) Slide 14

15. Folie 15 Data search in WISDOM: Example (ctd) Slide 15

16. Folie 16 Data search in WISDOM: Example (ctd) Slide 16

17. Folie 17 Request: Intersection of bounding box information Metadata Slide 17

18. Folie 18 Data search and Metadata: What is the connection? Tree structured keywords to categorize datasets Keywords written to metadata Keywords provided in both english and vietnamese Slide 18

19. Folie 19 Data Search and Metadata: Keywords in Metadata Slide 19 English and Vietnamese Keyword „Infrastructure“ written to Metadata

20. Folie 20 Data Search and Metadata: Search results Slide 20 Vector Data StatisticsDocument

21. Folie 21 Tools that support the generation of metadata for users Altova Formular Tool Online Metadata Tool (Data Entry Protal)  These ensure that metadata fit to search and search fits to metadata. Slide 21

22. Folie 22 Outlook This approach can be transferred to other systems, as we use standards! BUT: semantics differ between systems! Therefore, existing thesauri like GEMET should be used when defining project wide vocabulary Slide 22

23. Folie 23 Slide 23 Thank you for your attention! Malte.Ahrens@dlr.de