Analysis of Informa.on - III Efficiency of Graphic The efficiency - - PowerPoint PPT Presentation

Analysis of Informa.on - III

Efficiency of Graphic

• The efficiency of a graphic is determined as:

– To obtain a correct and complete answer to a given ques.on, all other things being equal, one graphic requires a shorter observa.on .me than another – Mental cost is lower

• Per.nent to the seman.cs of the ques.on
• Image theory: rules for construc.ng efficient

graphics

Stages in the Reading Process

• External Iden.fica.on

– The invariant and components – New informa.on is the discovery of new rela.onships among the known concepts

• Internal Iden.fica.on

– What visual variables each of the component is represented – The name of each component is inscribed on the planar dimension – Legends are necessary to define its exact meaning

Stages in the Reading Process

• External Iden.fica.on
• Internal Iden.fica.on
• Ques.ons can be formulated

– On a given date, what is the price of stock X?

Levels of Ques.ons

• Elementary level: ques.ons introduced by a single element of the

component and resul.ng in a single correspondence

– On a given date, what is the price for stock X?

• Intermediate level: ques.ons introduced by a group of elements or

categories and resul.ng in a group of correspondence

– Over the first three days, what was the movement of the stock X?

• Overall level: ques.ons introduced by the whole component

– During the en.re period, what was the trend of the stock X?

Image and Instant Percep.on

• To answer a ques.on, we need to have:

– An input iden.fica.on (a given date) – Percep.on of a correspondence (date vs price) – An output iden.fica.on (price on the date) – The eye needs to be able to isolate the input (date) from all the others and during an instant of percep.on to obtain the desired correspondence (stock price)

• Image: the meaningful visual form, percep.ble in

the minimum instant of vision

Example

• Invariant: volume of salaries paid by

enterprise

• Components: five branches (energy, transport,

industry, service, commerce) of

• Q percentage of salaries per branch, according

to

• Q Five categories (0, 1-5, 6-100, 101-500,

500+) of enterprise size

Example

• Invariant: volume of salaries paid by enterprise
• Components: five branches (energy, transport, industry, service,

commerce) of

• Q percentage of salaries per branch, according to
• Q Five categories (0, 1-5, 6-100, 101-500, 500+) of enterprise size

Ques.on

• For what category of enterprise size do we

find the largest volume of salaries paid in the commerce branch (easy)

Ques.on

• In what branch do we find the highest

percentage of salaries paid in the enterprise of

• ne to five workers?

Inefficiency of figura.ons

• In what branch do we find the highest percentage
• f salaries paid in the enterprise of one to five

workers? (hard)

• Figura.on – mul.ple images

Inefficiency of figura.ons

• Inefficiency is due to a large number of images the

viewer has to select and retain in order to obtain a correct answer

• Graphics below are hard to answer Immediate or
• verall ques.ons

Inefficiency of figura.ons

• Another ques.on: Is there a correla.on

between the volume of salaries and number

• f enterprise in each of the branches?

Efficiency of the Image

• Answer the ques.ons again:

– In what category of enterprise is the largest volume of salaries for the commerce branch? – In what branch is the highest percentage of salaries distribu.on in the enterprise of one to five workers?

Efficiency of the Image

• The most efficient construc.on are those in

which any ques.ons, whatever type and level, an be answered in a single instant of percep.on, that is, in a single IMAGE

Improved, but s.ll not efficient Add nothing to this good IMAGE

Construc.on of Image

• The Image is formed within a homogeneous field
• Any rec.linear scanning, suggested by the

construc.on, groups iden.cal elements

• The standard differen.a.on that is the most

effec.ve is orthogonal differen.a.on

The Use of Re.nal Variable

• Like the planar dimensions, which are

naturally ordered, the variable must be visually ordered in order to construct an image

• The image is formed by three homogeneous

and ordered variables, the two planar dimensions and an ordered re.nal variable

– Size, value, texture

Limits of Image

• When the informa.on requires more than

three variables, we cannot construct a figure which will provide an immediate response to all types of ques.ons

• An image will only accommodate a

reorderable component

– Because it does not allow an instant selec.on

Limits of Images

In a given area, what is the hair color? (easy) For dark hair, where are they? (easy) In a given area, what are the three characteris.cs? (hard)

Limits of Images

Where are the highest epha.c index? (hard) Both types of graphic in the previous two slides are needed

Limit of Images

At a point, what is the industry ? (easy) A given industry, where is it? (hard) Because spa.al dimension is highly selec.ve but shape is not.

Limits of Images

• In order to answer all types of ques.ons, it is

necessary to have:

Three Func.ons of Graphic Representa.ons

• Communica.ng more than three variables in a

graphic is a major challenge

• The use of graphic is to extend our memory
• Three func.ons of graphic representa.ons:

– Recording Informa.on – Communica.ng informa.on – Processing informa.on

Recording Informa.on

• Inventory drawing
• The plane and its visual signs are used to record all the

correspondences in a given informa.on set

– A storage mechanism – Avoid the effort of memoriza.on – Example: subway map

• First stage of communica.on - the .me required to

extract informa.on from it is less of a concern

• In the format of mul.ple images, does not allow

immediate answer to a ques.on, and hence does not serve as an effec.ve visual memoriza.on

Communica.ng Informa.on

• Retaining informa.on with the help of visual

memory

• The conveyed informa.on should be

memorizable

• The reading approaches the overall level
• Numerous choices are possible but the

number of images should be kept small whenever possible

Recording to Communica.ng

Processing Informa.on

• Ordering and classing
• Grouping
• Deriving new components or categories for

discovery, and make it easier to memorize

• Simplifica.on – starts from complex

informa.on and aims at making it understood

– Ordering a qualita.ve component – Elimina.ng certain correspondence

Processing Informa.on

Diagonaliza.on of Diagrams

• Any opera.ons of classing from orthogonal

coordinates tends toward the diagonal

• The perfect ordered correspondence (leb)
• Lack of order or noncorrespondence (right)

Diagonaliza.on of Two Components

• When the informa.on contains only one

selec.ve ( ) component

• When the informa.on contains two selec.ve

components

Diagonaliza.on of Three Components

• Order the third component

Elimina.ng Correspondences

• Smoothing, regionaliza.on, and generaliza.on

Rule of Legibility

• Graphic density

– Op.mal number of marks per unit area

• Angular separa.on

– Avoid squashing the plan which limits the angular difference

• Re.nal separa.on

– Separate the meaningful marks from the meaningless ones – Separate the steps in each re.nal variable

Graphic Density

• Legibility of figura.on: ten signs per com2

represent a maximum limit

• A homogenous graphic representa.on can

have a much larger density

– Larger density makes intermediate and overall readings much easier

Graphic Density

Figura.on - has a maximum density limit

Graphic Density

Homogeneous Graphic Representa.on

• Allows much higher density

Angular Legibility

• A visual form is delimited by a series of more
• r less clear lines which determine angles
• Angular legibility diminishes as

– The clearness diminshes – The angle approaches 0 or 180 degrees – The lines forming the angle shorten

• The choice of scale in a diagram is based on

angular legibility

Angular Legibility

Good for elementary reading Good for overall reading Compromise 70o 45o

Angle and Shape

• As the length of the lines diminishes, the angle

is no longer legible, hence the shape

• A legible shape needs to be at least 2mm in

size

• With smaller sizes there are only three dis.nct

legible shapes

– The point – The dash – The intersec.on of two dashes (i.e. the cross)

Re.nal Legibility

• To achieve the

maximum of re.na legibility:

– The total amount

• f black stays

between 5-10%

• f the display

area – Maintain the contrast between the subject (foreground) and the background

Reduc.on of the Background

• Elimina.ng known

signs

• Decreasing the

visibility of the remaining signs

• Accentua.ng the

presump.on of con.nuity

Percep.ble Quan.ta.ve Differen.a.on

• Essen.ally depends on the u.liza.on of the

maximum range based on size difference

• Easy to construct an image with 1 to 10 000
• S.ll legible for a ra.o of to 20, but legibility is

nil at 1 to 10

Percep.ble Order Differen.a.on

• Depends on the u.liza.on of the maximum

range of the ordered variables: size and value

• Order informa.on generally calls for selec.ve

percep.on as well

Bad Good

Combina.on of Variables

All combina.on of re.nal variables are possible

Combina.on of Variables

Combina.on of Variables

• A combina.on of variables will retain the

proper.es of the variables that have the highest level of organiza.on

Redundant Combina.ons

• A combina.on of

several variables to represent a single component

• Increase the

separa.on between the steps of the re.nal variables

• Enhance selec.ve

differen.a.on

Meaningful Combina.ons

• When two

variables are each associa.ve with a different component