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 one to five workers?
Inefficiency of figura.ons • In what branch do we find the highest percentage of 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 overall ques.ons
Inefficiency of figura.ons • Another ques.on: Is there a correla.on between the volume of salaries and number of 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 com 2 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 or 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 70 o 45 o Good for overall reading Compromise
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 of black stays between 5-10% of 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
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