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Automated generalisation of intermediate levels in a multi-scale pyramid
Marion Dumont, Guillaume Touya, Cécile Duchêne COGIT – IGN France
18th ICA workshop on Generalisation and Multiple Representation 21/08/2015
Motivations
2
Motivations
Source: IGN France 3
Motivations
4 Source: IGN France
Motivations
Source: IGN France 5
Multi-scale pyramid
Source: IGN France 6
Multi-scale pyramid
7 Source: IGN France
≠
Hypothesis
Source: IGN France 8
Hypothesis
9
?
Source: IGN France
Potential sources of disorientation
10
Discontinuities
Source: IGN France 11
Inconsistencies
Symbolization discontinuities
Source: ICGC Catalonia 12
Symbolization discontinuities
Source: ICGC Catalonia 13
How can we interpolate the intermediate representation?
Symbolization discontinuities
Source: IGN France 14
Symbolization discontinuities
15
Is the use of a single style required?
Source: IGN France
Content discontinuities
Source: BEV Austria 16
Content discontinuities
Source: BEV Austria 17
How can we improve these transitions? -> adding intermediate representations -> How design them?
Content discontinuities
Source: Google Maps, OpenStreetMap, Swisstopo
Source: IGN France, Google Maps 18
Content discontinuities
Source: Google Maps, OpenStreetMap, Swisstopo
Source: IGN France, Google Maps 19
How should evolve the density ? At which scale a LoD should be shown?
Content inconsistencies
Source : [Girres & Touya, 2014] 20
Content inconsistencies
Source : [Girres & Touya, 2014] 21
Research issues
22
What is a good intermediate level?
At which scale?
23
24 Source: ICGC Catalonia
At which scale?
25
Problem => intermediate level
Source: ICGC Catalonia
At which scale?
Source: IGN France
Scale
26
10K 50K
Problems
At which scale?
27
Scale 10K 50K
?
Source: IGN France
At which scale?
Which constraints?
28 Source: BEV Austria
Scale 50K 175K
29 Source: BEV Austria
Scale 50K 175K
?
Which constraints?
30 Source: BEV Austria
Scale 50K 175K
Degree of Generalisation
?
?
Which constraints?
Distance?
31 Source: BEV Austria
Which constraints?
Source: BEV Austria
Distance?
32
Distance = f(DoG, symbolization, data quantity, etc…)
Which constraints?
How to automatically generalise it?
33
Generalisation
?
Data source
34
Generalisation
Data source
Operators
How to automatically generalise it?
35
Generalisation
Data source
Operators Parameters
Scale
How to automatically generalise it?
36
Generalisation
Data source
Operators Parameters
Scale
Evaluation
How to automatically generalise it?
Source : [Brewer & Buttenfield, 2007; Touya & Girres, 2013] 37
How to automatically generalise it?
Source: IGN France 38
Links of generalisation
How to automatically generalise it?
How to validate our results?
39
Thank you for your attention
40
References
• Existing Multi-Scale Maps • BEV Austria http://www.austrianmap.at/amap • Google Maps http://www.google.fr/maps • ICGC Catalonia http://www.icc.cat/vissir3 • IGN France http://www.geoportail.gouv.fr/accueil • OpenStreetMap http://www.openstreetmap.org/ • Swisstopo http://map.geo.admin.ch/
• Literature • Brewer C, Buttenfield B (2007) Framing Guidelines For Multi-Scale Map Design Using
Databases At Multiple Resolutions, Cartography and Geographic Information Science, Vol. 34, No. 1, pp. 3-15
• Girres JF, Touya G (2014) Cartographic Generalisation Aware of Multiple Representations, Proceedings of GIScience 2014 - Poster session, (Eds) Duckham M, Stewart K, Pebesma E
• Schwartges N, Allerkamp D, Haunert JH, Wolff A (2013) Optimizing Active Ranges for Point Selection in Dynamic Maps, 16th ICA workshop on generalisation, Dresden
• Touya G, Girres JF (2013) ScaleMaster 2.0: a ScaleMaster extension to monitor automatic multi-scales generalizations, Cartography and Geographic Information Science, Vol. 40, No. 3, pp 192-200
41
