1. Influences on Data Quality Gerhard Navratil Institute for Geoinformation and Cartography 28.6.2006 GeoGeras

2. 2/xy GeoGeras Pernegg, 28.6.2005 Gerhard Navratil Outline Problem Technical Limitations Legal Factors User Needs Interrelations Combined Influences Conclusions

3. 3/xy GeoGeras Pernegg, 28.6.2005 Gerhard Navratil Problem (1) Tiers of Ontology (Frank 2001) Tier 0: Physical Environment Tier 1: Observation Tier 2: Objects Tier 3: Society Tier 4: Cognitive Agents

4. 4/xy GeoGeras Pernegg, 28.6.2005 Gerhard Navratil Problem (2) Tiers of Ontology vs. Quality Measures Tier 0: Physical EnvironmentNot necessary Tier 1: ObservationData Quality Tier 2: ObjectsUncertainty Tier 3: Society??? Tier 4: Cognitive AgentsFitness for Use

5. 5/xy GeoGeras Pernegg, 28.6.2005 Gerhard Navratil Problem (3) We need: Quality measures for influences of the society Derived from: Law texts Question: How can we connect the laws with the other influences? Presented here: Influences of society and user needs on the data quality

6. 6/xy GeoGeras Pernegg, 28.6.2005 Gerhard Navratil Problem (4) Different influences on data quality Technical limitation (process of data acquisition) Legal restrictions (society needs) User requirements

7. 7/xy GeoGeras Pernegg, 28.6.2005 Gerhard Navratil Technical limitations Higher quality  Higher costs Absolute limitation e.g. estimated relative standard uncertainty of 1m: 2,5*10 -11 Examples: Satellite images, GPS

8. 8/xy GeoGeras Pernegg, 28.6.2005 Gerhard Navratil Legal Restrictions Laws influence data quality by –Influencing data collection (cadastre, statistics) –Access restrictions Weak limitation (laws can be broken) Examples: Demographic data, data on spatial planning

9. 9/xy GeoGeras Pernegg, 28.6.2005 Gerhard Navratil User Needs Assumption: Larger number of users  higher data quality Evidence: Christoph Schlieder – data capturing with the help of communities Examples: Topographic maps (main user military), nautical maps

10. 10/xy GeoGeras Pernegg, 28.6.2005 Gerhard Navratil Interrelations Law-Technology: Legal restrictions to use possibilities provided by technology (land register) Law-Usability: Design of business process according to available public data (PSI, INSPIRE) Usability-Technology: Technological development thrives if needed

11. 11/xy GeoGeras Pernegg, 28.6.2005 Gerhard Navratil Combined Influences Orthoimages: Technology + Law e.g. Legal restrictions on flying heights, military security Marketing Data: Law + Usability e.g. data protection laws Cadastral Data: Usability + Technology created for tax authority and land owners (boundaries)

12. 12/xy GeoGeras Pernegg, 28.6.2005 Gerhard Navratil Conclusions There is an influence of laws, users, and technology on data quality These parameters are not independent There are measures to deal with technological influences Fitness for use deals with user needs A measure for legal (social) components is missing – fuzzy problem (laws are broken)

13. 13/xy GeoGeras Pernegg, 28.6.2005 Gerhard Navratil Thank You Questions? References for further reading Navratil, G. (2004). How Laws affect Data Quality. ISSDQ. Navratil, G. and A. U. Frank (2005). Influences Affecting Data Quality. ISSDQ. Navratil, G., C. Twaroch and F. Twaroch (2005). Nutzung von Katasterdaten - wie genau wird die Grenze benötigt? AGIT. Navratil, G. (submitted). Modeling Influences on Data Quality with Possibility- Distributions. ACM GIS.