Graphic interfaces of geoportals allow visualizing, sometimes overlaying often by image blending, various data and representations of geographical spaces: vector data, maps, aerial imagery, Digital Terrain Model (DTM), etc. After some previous works it appears that image blending is insufficient to allow efficient co-visualization of orthoimagery and vector data. Our purpose is to be able to manage an hybrid visualization of orthoimagery and vector data, efficient and useful. The diversity of hybridization levels requires to be able to control a continuum between such data. We thus have to propose rendering methods to mix heterogeneous data, in order to propose homogeneous and continuous intermediary representations. This paper proposes a methodology to interpolate graphic parameters between an orthoimage and related vector data, to control the level of orthophotorealism, all along the continuum. We detail the methodology based on several interpolation components, to control abstraction and realism levels, by manipulating colors and textures (natural, procedural or mixed).

1. Color and Texture Interpolation
Between Orthoimagery and Vector Data
Charlotte Hoarau, Sidonie Christophe
GeoVIS - ISPRS GeoSpatial Week - Thursday, October 1srt 2015

2. CONTEXT and CHALLENGES
Hybrid visualization between maps and imagery

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Long term purpose
 Modelisation of the cartographic style
 Style navigation between cartographic representations
→ Design method to create Cartographic Continuum
Topographic Map Imagery

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Design challenges
Create efficient hybrid visualizations
→ Avoid global image blending by transparency
→ Understand the perception of conveyed information
→ Create smooth transition to help cognitive tasks
(such as feature recognition, territory comprehension, etc.)

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Heterogeneous visual perception
02.07.1

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 Abstract representation of the real world
“All maps are abstractions of the reality”
[Robinson et Al. 95]
 Information is identified, interpreted,
structured and hierarchised
 Abstraction steps in the cartographic
process
 Data selection
 Data generalization
 Data symbolization
Topographic map perception

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Imagery perception
 Realistic representation from the sky
 Photo-realism effect
 Automated acquisition
 Continuous representation
 Non encoded information
 Increased credibility in a “ground truth”
 Difficult to interpret as “raw” data

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Question research
Orthoimagery Topographic map
 How to merge them into an hybrid visualization ?
 How to create visual and progressive transitions ?

9. METHODOLOGY
Visual properties interpolation

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Mixing imagery and vector data
Vector
Cartographic
Database
Raster
Imagery
Database
Hybrid
Visualization

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Merging visual properties : Color and Texture
 From the map : bright colors (conventional or abstract)
 From the imagery : natural textures and colors
 Procedural rendering methods

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Methodology
Determining pivot
symbolizations

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Pivot symbolization
 Using endings visual properties

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Pivot symbolization
 Using endings visual properties

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Methodology
Determining pivot
symbolizations
Interpolating
Symbolization
parameters

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Color interpolation
Applied to the hydrography
Map color Natural color

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Raster Color Interpolation

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Applied to buildingsgs
Natural texture interpolation
Plain color Transparent color

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Procedural texture interpolation
Applied to the vegetation
Procedural texturePlain color

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 How to choose pivot symbolizations ?
 How to combine parameter interpolations ?
Interpolation parameterization
02.07.1

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 How to synchronize cartographic themes ??
Imagery Map
02.07.1
Interpolation parameterization
Using the perceived realism level

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Interactive online user test
02.07.1

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 The texture is more relevant to control the realism level
 Validation of one interpolation combination
Main results on realism perception
02.07.1

24. CARTOGRAPHIC RESULTS
Realism-Abstraction Continuum

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Continuum design

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Continuum design

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Continuum design

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Continuum design
Color Interpolation Texture Interpolation

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Continuum design
Color Interpolation Texture Interpolation

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Cartographic Continuum

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Cartographic Continuum

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Cartographic Continuum

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Cartographic Continuum

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Cartographic Continuum

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Cartographic Continuum

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Cartographic Continuum
Style IGN Style OSM

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Cartographic Continuum
Style IGN Style OSM

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Cartographic Continuum
Style IGN Style OSM

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Cartographic Continuum
Style IGN Style OSMStyle IGN Style OSM

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Cartographic Continuum
Style IGN Style OSM

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Cartographic Continuum

42. CONCLUSION and PERSPECTIVES
Hybrid visualization between maps and imagery

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Cartographic continuum design
 Interpolating color and texture properties allows to
create smooth graphic transitions
→ How to evaluate the evolution of the perception by
merging representations ?

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 Integration of continuum in multiplexing tools
→ How to support specific cognitive tasks ?
Interaction with cartographic continuum

45. Color and Texture Interpolation
Between Orthoimagery and Vector Data
Charlotte Hoarau, Sidonie Christophe
GeoVIS - ISPRS GeoSpatial Week - Thursday, October 1srt 2015