1. 26-1-2016 Challenge the future Delft University of Technology Peter van Oosterom STW User Committee meeting, Oracle, Utrecht, 19 September 2012 Explanation of the STW/NWO project “Vario-scale geo-information”

2. 2 Vario-scale Topographic map series and the art of map generalization Map fragments from different source scales enlarged to same ‘scale’ for content comparision

3. 3 Vario-scale Multi-scale: a good option? Multi-scale databases: often multiple representation drawbacks: redundancy, fixed levels of detail  potential inconsistent Scaleless data structures: single representation with additional structure to access at any level of detail Often also spatial organization (clustering/indexing) Progressive transfer: keep sending more details (compare to raster formats: data pyramids, wavelets)

4. 4 Vario-scale 1 0.3 3 0.4 2 0.4 6 0.2 4 0.5 5 0.35 a b c d e f gi j l k h Step 0 Importance(u) = Area(u)*Class-Weight(u) Comp(u,v) = Length(Bnd(u,v)) * Class-Similarity(u,v)

5. 5 Vario-scale 1 0.3 3 0.4 7 0.5 4 0.5 5 0.35 a b c d e f gi j l h Step 1

6. 6 Vario-scale 1 0.3 3 0.4 4 0.5 5 0.35 a b c d e f gi j l h 7 0.5 Step 1 blg

7. 7 Vario-scale 3 0.4 8 0.6 4 0.5 5 0.35 m b c f gi j l h Step 2

8. 8 Vario-scale 3 0.4 4 0.5 5 0.35 b c f gi j l h 8 0.6 m Step 2 blg

9. 9 Vario-scale 3 0.4 8 0.6 9 0.6 m b c f n h Step 3

10. 10 Vario-scale b c f h 8 0.6 m 9 0.6 3 0.4 n Step 3 blg

11. 11 Vario-scale 8 0.6 10 0.7 m o p Step 4

12. 12 Vario-scale 8 0.6 m 10 0.7 p o Step 4 blg

13. 13 Vario-scale 11 0.9 q Step 5

14. 14 Vario-scale q 11 0.9 Step 5 blg

15. 15 Vario-scale 5 (V)4 (U) 3 (Z)9 (U) 10 (U) 6 (W)2 (Y) 1 (X)7 (Y) 8 (Y) 11 (U) 2 24 4 4 GAP face-tree

16. 16 Vario-scale 1 0.3 3 0.4 2 0.4 6 0.2 4 0.5 5 0.35 Resulting tGAP structure 12345 6 0.30.20.40.35 0.2 7 0.3 8 0.6 9 0.4 10 0.6 11 0.9

17. 17 Vario-scale 12345 6 0-0.30-0.20-0.40-0.35 0-0.2 7 0.2-0.3 8 0.3-0.6 9 0.35-0.4 10 0.4-0.6 11 0.6- 3 8 9 Selection of faces overlap search region & Importance = 0.38 8 0.6 9 0.6 3 0.4 Use tGAP structure

18. 18 Vario-scale tGAP principles 1.Variable scale: ‘near infinite’ amount of levels 2.Base level with most detailed geometry/topology 3.Create links/structure on top

19. 19 Vario-scale Generalized Area Partitioning-tree a ‘3D view’ Vermeij et al. 2003 proposed topological GAP-tree: edges and faces (with importance range, consider as height)  scale/imp with 3D prisms

20. 20 Vario-scale Support of non-area objects Support for non-area objects fits in tGAP structure: 1.Points: own table with importance range 2.Lines: same but now with reference to BLG-repr. 3.Also combine 2 less important lines in 1 (e.g. after removal of least important branch) This enables: the change from area to line (or point) representation at certain moment. Similar to normal GAP-structure when face is removed, but now it is also introduced in node or edge table (with link).

21. 21 Vario-scale Other generalization operations Consider collapsing of areas in lines (or points) Compute skeleton (medial axis), connect to neighbors P0P0 P1P1 P2P2 P3P3

22. 22 Vario-scale Result fits in tGAP structure (Ai & van Oosterom, SDH’02 more: Meijers, Savino, van Oosterom’12 in preparation) Weighted skeleton

23. 23 Vario-scale tGAP example 1.Collapse road (split area, merge neighbours) 2.Delete forest (merge with farmland) 3.Simplify boundary (between water/farmland) 1 2 3

24. 24 Vario-scale 2D+scale  3D integrated tGAP DAG to 3D structure Parent-child:  neighbour above-below

25. 25 Vario-scale Delta scale  no change at all or local shock

26. 26 Vario-scale Smooth tGAP Remove local shock  no horizontal faces Gradual changes  less vertical faces Resulting polyhedron  representation of single object for all its scales

27. 27 Vario-scale Delta scale  delta map

28. 28 Vario-scale Non-horizontal slice  mixed scale map

29. 29 Vario-scale Non-flat slice  mixed scale map (fish-eye example) x y S=0 S=0.5 source: Harrie et al, 2002, ISPRS Archives 34(4):237–242

30. 30 Vario-scale The highly challenging project goals Semantic aspect (incl. attributes) needs further attention Lower dimension primitives (lines, points) do also fit in the structure, but need further investigations Fast slicing, exploiting coherence between delta scale Include label placement in smooth-zoom Not per se object by object creation (but multiple objects in parallel) Sliver before disappearing Lot of implementing and testing needed (engineering)