Module – 2 Visualization Principles and History

Perhaps the first technique for graphically recording and presenting information was that used by

early man

period of human is prehistoric Paleolithic life or stone age example

Chauvet-Pontd’Arc Cave, located near Vallon-Pont-d’Arc in southern France. The Chauvet Cave contains over 250 paintings, created approximately 30,000 years ago. These were likely meant to pass on information to future generations.

logogram

a written character that represents a word.

The oldest writing systems used

pictures to encode symbols and whole words (lolograms)

earliest written document

Kish limestone tablet

Cartogram

map showing geographically diagrammatic statistics of various kinds usually by the use of shades, curves, or dots.

Early visualizations came about out of

necessity: : for travel, commerce, religion, and communication

Peutinger Map

one page of which is shown in the above figure, was an early road map of the 70,000 miles of imperial highways of a section of the Roman world, with roads (in red) and their approximate mileage. It adds key landmarks such as staging posts and distances between large rivers and forests. One interesting aspect of the map is that distances are distorted. East-west distances are scaled up more than north-south ones. Thus, Rome appears nearer to Carthage than Naples is to Pompeii. Such distorted maps arose for many reasons. Relative positions were more important than actual accuracy, and in some cases the distortions were due to the medium being used (the map itself is 22 feet 1.75 inches by 13.25 inches): “The archetype may well have been on a papyrus roll, designed for carrying around in a capsa [tool box]. As such, its width would be severely limited, whereas its length would not” [169]. The original map is now in the ¨Osterreichische Nationalbibliothek in Vienna, Austria.

John Snow’s Map wht does each bar represent

one deceased individual

what did john snows map show

there individuals who died far from that centre? Tufte stated, “Snow observed that cholera occurred almost entirely among those who lived near (and drank from) the Broad Street water pump. He had the handle of the contaminated pump removed, ending the neighbourhood epidemic which had taken more than 500 lives.” It is maps such as these that allowed one to explore and communicate geographical links to disease and other time-based events.

Minard’s Napoleonic march representation was a

a brilliant tour-de-force, presenting linked geographic and time-series data on a static representation. This is one of his last maps, perhaps to appeal the destruction of France through war. The map strongly emphasizes the loss of troops during the Napoleonic Russian expedition. The armies are represented as flows whose width corresponds to the size of the army, and time is annotated. The size of French army went from over 400,000 to 10,000. The image is one of the most reproduced and has often been used as a test of the capabilities of visualization systems.

Florence Nightingale’s presentation of monthly deaths within the army, comparing those who died in battle with those dying from other causes.

Blue represents the deaths from disease, red represents deaths from wounds, and black represents all other deaths

5 Stages of Decision-Making: stage 1

Defining the Problem:

why do we need to define the problem

clear understanding of the problem. If we don’t know, what we want to achieve it will be very difficult to analyze the data. Sometimes, while analyzing the data we come across situations where something gets added to the problem definition or the definition gets changed

when defining the problem we need to begin with what

have a problem statement.

how to arrive to the problem statement

asking questions which is related to the field of study.

5 Stages of Decision-Making: stage 2

Defining the Data Table:

while defining the data table we need to look at what?

aspects such as whether the data is sufficient for our problem or how this data can be utilized to solve the problem.

5 Stages of Decision-Making: stage 3

Adopting a Processing Language:

processing language implies

a kind of visual aid to use for the analysis.

Maximum visual  efficacy

•The visualizations should provide better understanding of the data.

Mobility of the image

•This is a fundamental point, because it is the internal mobility of the image which characterizes modern graphics. A graphic is no longer "drawn" once and for all; it is "constructed" and reconstructed (manipulated) until all the relationships which lie within it have been perceived. The practical possibilities for permuting the elements on a diagram are numerous. The means employed by the assistant are simple and within anyone's reach. For the permutation of rows and columns, special equipment is available. Remember that we live in an age of computers and electronic display screens, and that all such permutations can now be carried out by pressing a button.

5 Stages of Decision-Making: stage 4

Processing the Data:

Processing the Data:

simplifying without destroying

5 Stages of Decision-Making: stage 5

Interpreting and Deciding or Communicating

Decisions must be made based on

insights derived from processing the data and simplifying it without destroying it.

Perception

plays a very important role in the visualization process. The human visual system's abilities and limitations may change the visualization's intent.

Pre-attentive processing

is done by the human mind without paying any attention to the situation ahead, i.e., in parallel.

color, texture

Attentive Processing

focused attention.