Increasing dataset quality metadata presence: Quality focused metadata editor and catalogue queriables.

Transcription

1 Increasing dataset quality metadata presence: Quality focused metadata editor and catalogue queriables. Alaitz Zabala (UAB), Joan Masó (CREAF), Lucy Bastin (ASTON), Fabrizio Papeschi (CNR), Eva Sevillano (UAB) and Lorenzo Bigagli (CNR) Tuesday 25 th June

2 The GeoViQua FP7 project GeoViQua provides a set of scientifically developed software components and services that facilitate the creation, search and visualization of quality information on EO data integrated and validated in the GEOSS Common Infrastructure. GEO S&T Label Community building Pilot case studies C R O S S S B A Presenting Quality Information : From Dataset Quality to Individual Sample. 2

3 Embedding quality in all phases of the geospatial data exploitation DAB-Q: Query with quality information WMS-Q extension to relate data with spatialized quality layers GEOLabel Graphical picture that helps to evaluate data WCS-Q: GMLCov extension for spatialized quality layers (in project) NetCDF-U A way to supply spacialized quality layers (UncertWeb) Discover Evaluate Access Use Presenting Quality Information : From Dataset Quality to Individual Sample. 3

4 How to express quality Presenting Quality Information : From Dataset Quality to Individual Sample. 4

5 Presenting Quality Information : From Dataset Quality to Individual Sample. 5

6 Edit quality metadata Two main components of ISO19115 quality model. Presenting Quality Information : From Dataset Quality to Individual Sample. 6

7 DQ_Element Many components It is more effective that quality is presented next to the metadata about the same component Presenting Quality Information : From Dataset Quality to Individual Sample. 7

8 Generic quality indicator box for dataset level quality Applied at different levels depending on the quality component Presenting Quality Information : From Dataset Quality to Individual Sample. 8

9 Positional accuracy with the spatial reference system Presenting Quality Information : From Dataset Quality to Individual Sample. 9

10 Thematic accuracy, Domain and Format Consistency with the data model information The right quality indicator depends on the data type For quantitative values Presenting Quality Information : From Dataset Quality to Individual Sample. 10

11 Thematic accuracy, Completeness and Domain and Format Consistency with the data model For categorical values Presenting Quality Information : From Dataset Quality to Individual Sample. 11

12 Temporal component: Dates Creation and update dates of the dataset Measurement date (content date) Metadata time stamp Presenting Quality Information : From Dataset Quality to Individual Sample. 12

13 Temporal accuracy with the date of the measurement Presenting Quality Information : From Dataset Quality to Individual Sample. 13

14 Conceptual consistency Presenting Quality Information : From Dataset Quality to Individual Sample. 14

15 Topological consistency Presenting Quality Information : From Dataset Quality to Individual Sample. 15

16 Metadata per object or per pixel and quality per object or per pixel Sometimes a metadata element is not a constant for the dataset but is different for each object or for each pixel of the dataset. We talk about spacialized metadata or spacialized quality. In this case, the values of a metadata element are stored in a property of the data model. In some cases a property of the data model contains metadata for another property. A property contains a the values of the thematic accuracy or another property values (instead of the dataset itself). Presenting Quality Information : From Dataset Quality to Individual Sample. 16

17 Spacialized error We have implemented this for quality indicators. Presenting Quality Information : From Dataset Quality to Individual Sample. 17

18 Do you remember? Two main components of ISO quality model. Presenting Quality Information : From Dataset Quality to Individual Sample. 18

19 Lineage in (and ) Seems complete but We want to use lineage for reproducibility of the processes Currently it is not possible to describe nondataset parameters to associate sources to a parameter names Presenting Quality Information : From Dataset Quality to Individual Sample. 19

20 We also have WPS Web Processing Service is a service interface that allows to execute processes in a distributed environment DescribeProcess and Execute have its own XML language to describe the exact parameters and values involved in an execution. Each operation has a list of parameters that can be numbers, datasets, references to data services or bounding boxes. Each parameter as a name and an abstract. This allows the reproducibility of the processes Presenting Quality Information : From Dataset Quality to Individual Sample. 20

21 Just an example in ISO lineage Dataset Area affected at 50m ProcessStep Buffer Source Road to affect ProcessStep Extraction» Source» Topographic map Presenting Quality Information : From Dataset Quality to Individual Sample. 21

22 Combining ISO Lineage and WPS in the ex. Dataset Area affected ProcessStep Buffer Parameter Buffer distance=50m Source» ProcessStep * Parameter * Source Input layer= Source=Road to affect Extraction» Bbox=386000, ,386700, » Map= * Source=f276x090\bt5mv20mm0f276090vv0r030.arc Presenting Quality Information : From Dataset Quality to Individual Sample. 22

23 ISO Combining ISO lineage and WPS model ISO WPS ISO Presenting Quality Information : From Dataset Quality to Individual Sample. 23

24 Going back to the GeoViQua model GeoNetwork has been adapted to create, edit and publish GeoViQua-compliant metadata Harvested records can be used for discovery that considers quality. Presenting Quality Information : From Dataset Quality to Individual Sample. 24

25 Quality in CSW Catalogues Identify relevant properties (queryables) for quality-constrained queries GeoViQua user and technical requirements GeoViQua quality indicators GeoViQua quality GEO label Define and implement the quality extension to CSW-ISO (CSW-Q) Define and implement brokering logic (mapping and assessors) for GeoViQua services Feedback Catalog Harvest also services WMS-Q, SOS-Q Presenting Quality Information : From Dataset Quality to Individual Sample. 25

26 DAB-Q in context cmp GeoViQua DAB-Q GeoViQua GeoViQua catalogue WAF GeoViQua Capacity Common services GEO Web portal search Producer data access WMS-Q CSW-Q Search by grafic WMS-Q CSW-Q GEO DAB-Q CSW-Q Sensor Registry Q SOS-Q + SensorML CSW-Q Search-Q KML-Q Emiter + 3D view + color pal. Capacity Catalogues exposed in md id FeedBack Catalogue REST (GET XML) Presenting Quality Information : From Dataset Quality to Individual Sample. 26

27 CSW-Q extension Presenting Quality Information : From Dataset Quality to Individual Sample. 27

28 Demo portal Presenting Quality Information : From Dataset Quality to Individual Sample. 28

29 Conclusions Quality indicators can be better interpreted if associated with their respective metadata components Quality indicators at the dataset level are not enough and we need to extent both the granularity and the scope quality indicators Current lineage is detailed but it does not allow reproducibility yet Complement it with WPS Execute encoding can help Quality queriables are needed in catalogues for better dataset discovery and ranking Presenting Quality Information : From Dataset Quality to Individual Sample. 29

30 Thanks! The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/ ) under grant agreement no