Acceptation of Earth observation information by GIS users

1. Acceptation of Earth observation information by GIS users Edwin Wisse National Aerospace Laboratory, Space Department UNIGIS intake march 2002 16 June 2006

2. Introduction: Earth obseravtion • History • 1972, Landsat-1 first dedicated Earth observation satellite • 1986, SPOT-1: 10 metre panchromatic, 20 metre multispectral • 1991, ERS-1: imaging radar • 1999, Ikonos: high resolution optical satellite (1 metre pan, 4 metre multspectral) • Applications • Scientific • Agricultural and environmental • With hogh resolution satellites: planning and surveying Acceptance of Earth observation

3. Introduction: acceptance • Earth Observation has so far failed to evolve into a mature and self-sustainable operational or commercial activity. Hence, it has not allowed the development of a service industry of any economic significance. (Achache, Director of EO ESA, 2003) • In numbers: • Public sector (mostly defense) forms 64% of the market. • Private sector: mostly telecommunications (planning mobile phone networks) plus oil and gas • Annual growth over 1998-2000: 1.4% (that’s decline) • Problems and solutions • Findability. O2 (ESA): build infrastructuur • Availability. Rapideye: use Constellations • Usability. Error and resolution aspects are not sufficiently understood and applied • But what are exactly the weaknesses in Earth observation according to users? Acceptance of Earth observation

4. Introduction: ideal Earth observation • Satellite watches over Duckburgh constantly (temporal resolution) • Fine tune button for easy zooming (spatial resolution) • It’s free! • Images can be received from the air (availability) • What you see is what you get (error aspects) Acceptance of Earth observation

5. Study problem • The question we want answered is: • What factors are decisive in user acceptance of Earth observation information by GIS users? • This can be formulated as two consecutive questions: • What are the different factors? • How strong do they affect acceptance? • Why GIS users? • Talks with other UNIGIS students showed me that most found EO very interesting and promissing, but very few were aactually using it. • But how can we test acceptance? Acceptance of Earth observation

6. Technology acceptance model • Based on the theory of reasoned action, people base their decisions on a chain of factors. Intention to use affects actual usage, and the attitude of a person affects intention. • This was extended to the Technology Acceptance Model. In TAM usefulness and ease of use are introduced. These affect the attitude. • TAM contains methodology for measuring the strenght of the constructs. • TAM has been used to test acceptance of software tools, phones, services etc. Acceptance of Earth observation

7. Technology acceptance model Acceptance of Earth observation

8. Technology acceptance model • TAM uses a standard scale to measure the relations between the contructs: • Using TestTool in my job would enable me to accomplish tasks more quickly • Using TestTool would improve my job performance • ... • It would be easy for me to become skilful at using TestTool • I would find TestTool easy to use • Standard TAM is based on the perceived usefulness and ease of use constructs. • In later studies factors affecting the constructs have been introduced: enjoyment, functionality, interactivity etc. Acceptance of Earth observation

9. Earth observation: sensors and image types • Optical • easy to interpret • hindered by cloud cover, especially over the Netherlands • high resolution means small swath • with high resolutions the look angle of the sensor and shadows become significant • Radar: • looks through cloud cover • coarse resolution • sensitive to different materials than optical Acceptance of Earth observation

10. Earth observation: (classified) maps • Thematic maps from EO images: classified maps • Use spectral models to derive soil type, vegetation from pixel values • More channels (colours) give better results • Coarser resolution gives better results • Classified maps either errors (wrongly classified pixels) or they are incomplete Acceptance of Earth observation

11. Earth observation: parameters What are the factors affecting acceptance? (see study problem) • Spatial resolution • Temporal resolution • Errors and uncertainties • Representation: file format, how is the data delivered? • Availability: how to find data? • How do these parameters relate to the usefulness en and ease of use constructs? Acceptance of Earth observation

12. Modified TAM for Earth observation Acceptance of Earth observation

13. Modified TAM: the scale • The modified scale was designed to measure the affect of the parameters on the constructs: • The spatial resolution of optical images is sufficient for my needs • Optical images are acquired often enough for my needs • Thematical maps (classified images) with a classification error are usable for me • An error-free, but incomplete, thematical map or classified image is useful for me • ... • Importing Earth observation imagery and information into my GIS environment is easy for me • I know how to find and order the Earth observation images I need • An additional 4 questions from the standard scale were introduced to measure the affect of intention. Acceptance of Earth observation

14. Questionnaire session • ArcGIS user day at NLR: • Presentations about EO • Visit to ground station • En de questionnaire sessie • Session: • Controlled environment • 2 sessions of 14 people • Text of the presentation was read from paper • The subjects used a voting remote control • Interactive interface to select, compare and zoom into sample images Acceptance of Earth observation

15. Results: the subjects group • The subjects group: • Predominantly GIS users with little EO experience (good!) • More than half were from government: municipalities and provinces • Subjects who indicated that they had daily experience with EO were excluded from the following analysis.This left 25 subjects Acceptance of Earth observation

16. Results: spatial resolution • The subjects rate: • traditional EO imagery (10 metre resolution) neutral • high resolution imagery more usefull • radar imagery negative Acceptance of Earth observation

17. Results: temporal resolution • The subjects rate: • Despite the differences between optical and radar there is little difference in the responses • All subjects are neutral to positive to the temporal resolution issues Acceptance of Earth observation

18. Results: error aspects • Error aspects related results: • Incomplete maps as more useful than maps with errors • A georefencing error is not acceptable • Visulatisation of errors in GIS leads to high perceived usefulness Acceptance of Earth observation

19. Results: usefulness and ease of use constructs • 4 questions refered directly to the usefulness and ease of use constructs • Subjects are neutral to positive about usefulness • They see no problems with ease of use Acceptance of Earth observation

20. Results • Reliability: • The wide spread of he questions has resulted in a low, but acceptable reliability. • Correlations: • Strong correlations between spatial, temporal and error paramaters and perceived usefulness. • Also a strong correlation between representation and availability and the perceived ease of use. • Smaller (but significant) correlation between perceived usefulness and intention to use. • The perceived ease of use construct is weak in the modified TAM (but that was to be expected) Acceptance of Earth observation

21. Conclusions • Earth observation and GIS: • Subject group needs high resolution data (1 metre is still not sufficient), acquisition is already often enough for this group. • They are aware of the different errors and would like to see error representation in their GIS application. • Representation and availability are not seen as problems. • Modified TAM: • Good first result • Ease of use is weakly defined • Future study: use less parameters (and more subjects) • Unigis: • Unigis provides an excellent opportunity to step out of your own field of expertise and learn something different Acceptance of Earth observation