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Fieldwork: the role of validation in geo-information science

Fieldwork: the role of validation in geo-information science. Lammert Kooistra Contact: Lammert.Kooistra@wur.nl. RS&GIS Integration Course (GRS-30806). “real”. land use. error matrix. validation. Geo-information cycle. source: www.lgn.nl. Solution: fieldwork. Overview.

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Fieldwork: the role of validation in geo-information science

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  1. Fieldwork: the role of validation in geo-information science Lammert Kooistra Contact: Lammert.Kooistra@wur.nl RS&GIS Integration Course (GRS-30806) Centre for Geo-information

  2. “real” land use error matrix validation Geo-information cycle source: www.lgn.nl Centre for Geo-information

  3. Solution: fieldwork Centre for Geo-information

  4. Overview Fieldwork assignment (lecture 1) • Theory of validation • Validation in practice: the validation plan • The fieldwork assignment • Case studies • Available datasets and equipment • Planning • Role, communication & contact with coach Writing a scientific paper (lecture 2) Practical issues (lecture 3) Centre for Geo-information

  5. (geo-spatial) model development cycle landscape openness MODIS NDVI source: Sargent (1998) Centre for Geo-information

  6. Definition of validation • Modeling domain (GMP Manual Part 1 (p. 3-7)): validation is used to check the suitability of the model to simulate an independent data set (i.e. not used in calibration) • RS domain (CEOS WGCV): validation is the process of assessing by independent means the quality of the data products derived from the system outputs (from Liang, 2004) • Spatial modeling domain (Sargent, 1998): substantiation that a computerized model within its domain of applicability possesses a satisfactory range of accuracy consistent with the intended application of the model • verification (Sargent, 1998): ensuring that the computer program of the computerized model and its implementation are correct Centre for Geo-information

  7. Operational validation classification source: Sargent (1998) Operational validity • Returns measure of accuracy • Of interest for end-user • Assessment of processing algorithms • Determination of sources of uncertainty Centre for Geo-information

  8. Example 1: landscape enclosure • Comparison of spaciousness: • field and photograph observed • calculated with model (topographic features) source: Palmer&Roos (1998) Centre for Geo-information

  9. Example 2: MODIS LAI 2. sampling in 1 x 1 km area 3. comparison of MODIS based LAI with field LAI 1. study area: savanna source: Tian et al., 2002 Centre for Geo-information

  10. Example 3: global land use • http://www.confluence.org Centre for Geo-information

  11. Validation and scaling Example of fieldwork activities: field spectroscopy, hemispherical camera, species composition Example of flux tower in the field (above) and distribution of RS based observation net- works over the globe (left) Centre for Geo-information

  12. Fieldwork assignment • Investigate role of validation in geo-information cycle based on a case study for the Achterhoek area. The final result of this assignment is an individual paper. • Activities: • Introduction to case study (= spatial model) • Preparation of validation plan • Make field measurements • Analyze results • Write individual paper Centre for Geo-information

  13. Case studies • Group 1: Validating visibility measures to estimate perceived landscape openness (Gerd Weitkamp) • Group 2: Remote sensing based mapping of biomass and canopy water content for natural grassland ecosystems (Lammert Kooistra) • Group 3: Sensing recreational use of the environment (Arend Ligtenberg) • Group 4: Characterization of vegetation roughness using 3D-GPS (John Stuiver) • Group 5: Remote sensing based monitoring of Natura2000 area Korenburgerveen (Harm Bartholomeus) • Group 6: Accuracy assessment of the LGN land cover data base for the Netherlands (Jan Clevers) Centre for Geo-information

  14. Validation plan • Structured description of validation methodology for a specified spatial model and a specified domain of application • Descriptive, reproducible, from general to detailed • http://eospso.gsfc.nasa.gov/validation/terraval.php • http://www.daac.ornl.gov/DAAC/PI/bestprac.html Spatial model Real world Validation plan Evaluation Fieldwork Centre for Geo-information

  15. Components of a validation plan • Which (geo-spatial) model • Which (independent) variables • Which quality parameter • Which sampling scheme • Which spatial and temporal extent • Which (geo) data • Which (field) instruments • Which measurement protocols • Which field forms • Schematic presentation of methodology in flow chart Centre for Geo-information

  16. Validation plan: background and objective • Which (spatial) model • Which (independent) variable(s) will be validated • Which quality parameter: evaluation • Formalize complete methodology in flowchart Centre for Geo-information

  17. Validation plan: sampling strategy • Which sampling scheme • Which spatial and temporal extent • Locations • Measurements in time • Stratification • Prior knowledge/data Centre for Geo-information

  18. Validation plan: data and instrumentation • Which (geo) data • Which (field) instruments Centre for Geo-information

  19. Validation plan: implementation • Which measurement protocols • Which field forms • Preparation of (digital) field maps During fieldwork: • Store and back-up data • First check of results in “field office” Centre for Geo-information

  20. Available data and equipment • See website: http://webgrs.wur.nl/cgi/courses/grs30806/ • Under Fieldwork/case studies Centre for Geo-information

  21. Planning • Preparation in Wageningen: 3, 5 and 6 June: • Introduction to case study • Preparation of validation plan (incl., data and instruments) • Feedback from coach • Fieldwork in Achterhoek: 8 June (19:00) – 13 June • Arrival Sunday June 10 from 19:00 • Reconnaissance study area + testing instruments • Test measurement protocols • Measurements according to validation protocol • Check and first analysis of results • Field presentation of results: feedback from coaches • Paper writing in Wageningen: 17 June – 27 June Centre for Geo-information

  22. Role, communication & contact with coach • Providing students with background information and knowledge on topic • Judge the validation plan during the preparation week • Assist and provide feedback during fieldwork week • Judge results of field presentation and give feedback • If required assist students during elaboration of results • Judge the final result of case study: the individual papers Centre for Geo-information

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