color for online mapping: still difficult to choose by beate weninger (g2lab, hcu hamburg)

beate.weninger@hcu-hamburg.de @beaweb

Color for Online Mapping:

Still Difficult to Choose

ICC 2013 pre-conference workshop "Mapping in a digital world"

Motivation

Official traffic noise map of the city of Hamburg Color scale according DIN 18005-2

Color and Cartography // Color Advice

Colors of a scale should according to Levkowitz (1996): 1. „Preserve the order of the original values“; 2. “convey uniformity among values they are

representing, and representative distances between them; and

3. create no artificial boundaries that do not exist in the original data.”

Color and Cartography // Guidelines

Color and Cartography // Color Perception

Physical reactions, e.g.

Simultaneous contrast (1) Perception of object size Effect of object size Depth effect (2)

Lübbe 2013

(2)

(1)

Color and Cartography // Color Perception

Psychological reactions, e.g.

Color perception is influenced by the object (shape) Emotional reactions Trust issues

Color and Cartography // Color Perception

Color vision deficiencies

Official color scale according DIN 18005-2 transformed

Color Design Aspects for Webmapping

1. Harmonical hierarchy

Only systematic variation of lightness and saturation Consider spatial distribution for balanced scales (order,

complexity, object size) 2. Nature of the Scale: logarithmic etc. 3. Consistency 4. Qualitative meaning 5. Consider CVDs and situational CVDs

Design Challenges

Variety of screen sizes and use cases

Practitioners‘ wish list Many classes Flexible scale Traffic light system

New Scale // Qualitative Aspects

Different hues in a harmonical order with few lightness steps per hue supports recognition!

Card sorting task showed: users would order greens differently!

New Scale // CVD

Normal Vision deuteranopia (green-blindness) protanopia (red-blindness)

Conclusion // Focusing on Neocartography

How can we abandon rainbow and traffic light schemes? (Why are they still available in software?)

Do screen sizes and use cases effect color perception?

Clear rules are needed that support map-makers from a

non-traditional background ColorBrewer 2.0 extension?

Let`s bring the topic back on the to-do list!

Conclusion // Focusing on Neocartography

How can we abandon rainbow and traffic light schemes? (Why are they still available in software?)

Do screen sizes and use cases effect color perception?

Clear rules are needed that support map-makers from a

non-traditional background ColorBrewer 2.0 extension?

Let`s bring the topic back on the to-do list!

# What’s the map-maker’s aim? (raise awareness, bring forward an argument, aesthetic map…) # What’s most important: discriminability of colors, trust in the map, visualize distribution of values… # Is there a critical value in the scale that should be highlighted? # ….

More on Color

ICC Papers on color: Weninger: The Effects of Colour on the Interpretation of Traffic Noise in

Strategic Noise Maps

Kröger, Schiewe, Weninger: Analysis and Improvement of the OpenStreetMap Street Color Scheme for Users with Color Vision Deficiencies

beate.weninger@hcu-hamburg.de @beaweb

References

Levkowitz, H. (1996). Perceptual Steps along Color Scales. International

Journal of Imaging Systems and Technology 7, 97–101.

Lübbe, E. (2012). Farbempfindung, Farbbeschreibung und Farbmessung: Eine Formel für die Farbsättigung. Springer: Berlin, Heidelberg, New York.