Texture and Glyph Design

digital-media@rgutexture and glyph design

what are we looking at?

Texture: Theory and Data Mapping

Integral and Separable Dimensions: Glyph Design

Representing Quantity

Perceiving Patterns in multi-dimensional Data

WHAT IS TEXTURE?

the gabor function

the gabor function

The gabor function / filter is a process that is used for edge detection

We don’t need to understand the maths, just how it works.

Worth understanding as the function works in a very similar way to human perception

the gabor function

“A number of electrophysiological and psychophysical experiments show that V1 and V2 contain large arrays of neurons that filter for orientation and size information at each point in the visual field. These neurons have

both a preferred orientation and a preferred size (they are said to have spatial and orientation tuning). They are either weakly color coded or not

color coded, responding to luminance patterns only.”

the gabor functionTexture segmentation is the name given to the process whereby the brain divides the visual world into regions based on texture.

the gabor function

Primary Perceptual Dimensions of Texture

Orientation O: The orientation of the cosine component

Scale S: The size – 1/(spatial frequency) component

Contrast C: An amplitude or contrast component

Texture Contract Effects

Other Dimensions of Visual Texture

Nominal Texture Codes

Nominal Texture Codes

1 2 3 4 5 6

In order to make a set of nominal coding textures distinctive, make them differ as much as possible in terms of dominant spatial frequency and orientation components.

As a secondary factor, make texture elements vary in the randomness of their spacing.

Using Texture for Univariate and Multivariate Map Displays

Use simple texture parameters, such as element size or element density, only when fewer than five ordinal steps must be reliably distinguished.

To display a bivariate scalar field, consider mapping one variable to colour and a second variable to variations in texture.

Quantitative Texture Sequences

TemperaturePressureWind Speed

a glyph is a graphical representation of something else

nominal ordinal interval ratio

MikeMarkJohn

Strongly AgreeAgree

Disagree

47

15Kelvin

“Will the color-coding scheme interfere with our perception of glyph size and therefore distort

perceived population level?”

“What if we use both color and size to represent a single variable—will this make the information clearer?”

SEPERABLE

Integral

The distinction between integral and separable dimensions

Restricted Classification Tasks

Task is created with layout similar to this

Restricted Classification Tasks

Speeded Classification Tasks

Speeded Classification Tasks

Interference

Interference

Redundant Size

Redundant

Colour & Size

If it is important for people to respond holistically to a combination of two variables in a set of glyphs, map the variables to integral glyph properties.

If it is important for people to respond analytically to a combination of variables, making separate judgments on the basis of one variable or the other, map the variables to integral glyph properties.

Integral-Separable Dimension Pairs

Experiment TimeYou will be shown a dimension pair and an image. Your

task is to determine how many are in each category

Group Location

Colour

black and red

left and right

easy?lets try a few…

Motion

Colour

Shape Type

Colour

Size

Orientation

x-Size

y-Size

Red-Green

Yellow-Blue

That last one was mean(sorry)

Size

BrightnessHeight

Orientation

When designing a set of glyphs to represent quantity, mapping to any of the following glyph attributes will be effective: size, lightness (on a dark background), darkness (on a light background), vividness (higher saturation) of color, or vertical position in the display.

1D 2D 3D

Ideally, use glyph length or height, or vertical position, to represent quantity.

If the range of values is large, consider using glyph area as an alternative. Never use the volume of a three-dimensional glyph to represent quantity.

Representing Absolute Quantities

Multidimensional Discrete Data: Uniform Representation versus Multiple Channels

Spatial Position Position in Space (x, y, and z) 3

Colour Defined by colour theory 3

Surface Texture Orientation, Size, and Contrast 3

Motion Coding Movement (more research needed) 2 or 3

Shape Size and Orientation 2+

Blink Coding On / Off 1

In general, the use of heterogeneous display channels is best combined with meaningful mappings between data attributes and graphical features of a set of glyphs.

Stars and Whiskers

What happens if no natural mappings exist?

Whisker and Star plots can be used

1d and 2D

Size Colour Shape

Colour

4D and 5D

The Joy of Stats

6D and more!

The sky is the limitas designers, you should be able to come up with

solutions to visualisation problems

RECAp…





Texture and Glyph Design

Design

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