1. The Meaning of Geographic Expressions Dr Kristin Stock kristin.stock@nottingham.ac.uk

2. Q. These houses look like: 1.Comfortable homes 2.A retirement village 3.A slum 4.Mansions

3. Q. I would describe this geographic feature as: 1.A hill 2.An island 3.A volcano 4.A cay

4. Little round planet In a big universe Sometimes it looks blessed Sometimes it looks cursed Depends on what you look at obviously But even more it depends on the way that you see Bruce Cockburn

5. What does it all mean?

6. How Do People Think?How Do Computers Think?

7. Bridging the gap...

8. What is a geographic expression? National Parks near Nottingham. Walking paths in the Peak District. The river is opposite the museum. The library is around the corner from the market square. The castle is near here. Which rivers go through the Lake District? Which mountains in the Alps are steep? Where is a large lake near Nottingham?

9. Geographic Expressions are made up of... Geographic Features Spatial Relations Geographic Qualifiers

10. Geographic Features Objects that have a location relative to the earth. Natural, person-made or administrative. Categories or instances (instance = a specific object). Usually nouns in English.

11. Spatial Relations Words that describe the relationship in space between two features. Usually verbs in English.

12. Geographic Qualifiers Further restrict or qualify a geographic feature. Sometimes vague in interpretation. Usually adjectives in English.

13. Q. The parts of these expressions shown in red are: National Parks near Nottingham. Walking paths in the Peak District. The river is opposite the museum. The library is around the corner from the market square. Is the castle near here? Which rivers go through the Lake District? Which mountains in the Alps are steep? Where is a large lake near Nottingham? 1.Geographic object categories 2.Geographic object instances 3.Spatial relations 4.Geographic qualifiers

14. Q. An example of a spatial relation is: 1.around the corner 2.go through 3.tallest 4.Nottingham 5.River 6.step-mother

15. Q. ‘large’ is: 1.A geographic object category 2.A spatial relation 3.A geographic qualifier 4.A geographic object instance 5.An administrative relation

16. Spatial Relations Exercise

18. Q. I would describe this geographic feature as a: 1.Creek 2.Beck 3.River 4.Stream 5.Road

19. Q. I would describe this geographic feature as a: 1.Hill 2.Hillock 3.Mountain 4.Tor 5.Munro 6.Pingo

20. How do the meanings of geographic expressions vary? Culture. Background. Education. Environment. Context (dynamic).

21. So, how do people think about geographic features? Differently from each other (to varying degrees). Sometimes vaguely. Sometimes context sensitively.

22. But, how do computers think about geographic information?

23. Geographic Expressions Have a precise, fixed meaning: – The same for everyone; – Not context sensitive; – Not vague. Have rigid, crisp (not fuzzy) physical boundaries.

24. Geographic Features Census output area polygons, lower level super-output area polygons, ward polygons. County polygons. National Park polygons. Road network. Buildings from Historical Digimap.

25. Spatial Relations Query operators allowed by ArcMap: – Intersect – Completely contain – Share a line segment with – Touch the boundary of – Have their centroid in Like geographic features, spatial operators in GIS are also crisp and rigid.

26. Q. Which spatial operator would you use to: ‘find the buildings in Smith Street?’ 1.Contains 2.Crosses 3.Overlaps 4.Touches 5.Within 6.Near

27. Q. How would you query geographic qualifiers (steep, large) in a GIS? Geographic Qualifiers 1.I would look for an attribute containing the relevant information. 2.I would look at the spatial relations to try to deduce the qualifier values. 3.I would ask the person next to me. 4.I wouldn’t.

28. Summary People think uniquely, context-sensitively, sometimes vaguely. Computers think precisely, crisply, uniformly. When using current mainstream GIS, people have to bridge the gap. We are working on ways to help computers bridge the gap...