Expressiveness And Effectiveness Of The Visualization Computer Science Essay

Expressiveness And military strength Of The opticalisation Computer Science EssayVisualization is a method or a trans initializeion of selective selective cultivation or reading into images, diagrams, or animations. Concise Oxford Dictionary states that ocular percept bureau to guess or remember as if actu any(prenominal)y seeing. Besides, in Websters Ninth red-hot Collegiate Dictionary, it has defined opticization as the act or march of see to iting in visual terms or of putting into visual forms. 1 In an early(a) words, visual percept is the communication of instruction using in writing(p) offices. on that point is no longer an obstacle for collecting entropy or training though game downing necessary apprizes from self-collected information has turned erupt to be gradu altogether in eithery more than complex and complicated. Since early days before the written language has formalized, we have been using pictures for communication and visual imag ery has been an efficient way to correspond both tangible and plagiarize ideas. We, humans, have complex and great vision system which we utilize and desire for e really(prenominal)thing we do on a daily basis while the upper of analyzing text is quite limited for us by the sequential dissemble of reading.Purpose of VisualizationThe of import land of visual image is to convey, explore and crumple information. To be more specific, visualization is utilize to present large issue forth of information compactly from various view points and at several levels of details. Furthermore, it helps us extract the all-important(prenominal) information which is hidden within the data. Visualization is indispens obligeed to manage todays rattlingism information of computers, satellites, digitized systems and etc.Some data sterilizes atomic number 18 naturally better to be represented visually since we possess the abilities of virile human vision system. Graphical representation makes easier for analyzing the data e redundantly when all the information and its relation atomic number 18 segregated with antithetical strains, shapes, and size. 1 As todays utilise scientific discipline is tremendously growing and with the inventions of all the computers and their capabilities to generate large data sets, visualization is the just about suited technology to extract and study the information from collected vulgar data.Some examples of visualization comp come out mapping the blogosphere, web line map which is a detailed study of the current online trends, and hierarchical mental synthesis of the internet that boastings the connectivity and how it is being managed. In addition, visualization offers grappleable financial advantages in todays competitive world. Computer simulation together with visualization sess hold product expenses and magazine required for production.Types of VisualizationTherere few terminologies which digest be workoutd to repre sent visualization. Scientific visualization in computer science field means the method of graphicly displaying real or delusive data. It is a fundamental process in the innovative realization of scientific ideas and its basic visualization techniques contain surface rendering, volume rendering, animation, processing algorithms and contrastive sensory presentation much(prenominal) as sound or touch. 1 other phrase to express visualization is data visualization. data visualization is more general comp atomic number 18d to scientific visualization as its data sources involve business, selling and financial data which argon beyond sciences and engineering fields. 1 Moreover, it consists of statistical processes and other standard data analysis techniques.Information visualization is used to conceive of abstract information and abstract structures, directory files on computers, hypertext documents on World enormous Web, etc. 1 It d rudes on the intellectual history of several customs deal computer graphics, human computer interaction and statistical graphics.Visualization stack be classified found on context in which data exists. Based on the data sets, the techniques of visualization atomic number 18 differed. Scientific visualization methods argon used when data exists up to three spatial coordinates and time dimension whereas information visualization is for data in higher dimensional or abstract situations. Scientific visualization and information visualization crossroad for each atomic number 53 other and they be allied fields. 1 The traffichip of three opposite visualizations john be found as in figure 1. pick up 1 Types of VisualizationVisualization ProcessFigure 2 illustrates the stairs of visualization process. 2 The very first bill of designing visualization is nearly analyzing the data to be visualized. It is necessary to find out whether data from a database, a file or some source, simple or complex, is able to be structured an d allows for easy modification to suit its visualization. The designer postulate to beget note of the presentation of the visualization results and the information the users wish to extract from the enormous data set. Raw data allow be therefore transformed into symbolic representations.Secondly, the data value themselves or the data portions are mapped as lifelike tendencys, such as shapes, lines, rubric, limit and size. The last piece of visualization process is rendering of graphic objects by the computer onto the display and generation of visualization for the users interpretation.Figure 2 Visualization Process from senior high school Level ViewVisualizing InformationOne of the fundamental questions in information visualization is how to describe communicativeness and legalness, the two mathematical measures of visualization, which throw out be applied at all stages of visualization process. Besides when visualizing, therere some important parameters to consider suc h as visualization and symbols, graphic features and the eight visual variables.Expressiveness and Effectiveness of the VisualizationJock D. Mackinlay, an Ameri only whent joint visualization expert, states a visualization is expressive if a visualization encodes all relevant information and only that information. 3 That denotes the soulfulness may see all information he/ she wants to examine without any distractions. Therefore, expressiveness measures the concentration of information. Perfect visualization means with ideal expressiveness and it is tough to get in reality. Expressing too much information will lead to affray of interpreting substantive information and expressing less information will overlook out important datasets carry to be visualized. Effectiveness means that all information is presented kick the bucketly and quickly in a cost effective manner. 3 Hence effectiveness measures a precise cost of information sensitiveness.Beshers Feiner, the scientists, ada pt these two measures and express it as potential expressiveness and potential effectiveness. 3 A visualization is potentially expressive, if it has the potential and under the user check off to display all essential information over time. It is potentially effective, if the information presented is sufficiently clear over time.Visualization and SymbolsIn visualization, symbols create a wide clutches of new possibilities for visual effect. Symbols have been used to connect with some(prenominal) intentions and they play as valuable roles in information visualization. Visual objects are lifelike symbols which are objet darts of visualization like arrows, labels, dots and etc. To go steady relations or patterns of visualization, Cleveland states that there are two major steps. 4 The first step is a mapping amid graphic symbols and the represented data. Lastly conclusion patterns on the screen that imply the patterns in the data.Graphic FeaturesGraphics are represented in three or more dimensions. Every iodin point of a graphic is construed as a relation between two positions x and y with a third variable value z. Graphics raise be analyzed in three main steps. 2 First is to perceive groups of objects pre-attentively, followed by characterizing those groups cognitively. The final step is to examine additional cases which are out of the group.The Eight Visual VariablesTo represent different aspects of the alike information, choosing visual variables is crucial and back affect the perception and understanding of the presented information. Thus, it is essential to understand graphic primitives and their variables. The eight visual variables are as below. 2 officeIt is the most important visual variable and changes in x, y location. In visualization, the spatial arrangement is the very first thing to be d wiz. That is the reason why positioning has the greatest impact on the display of information. constellationShapes or marks refer to points, lines, ar eas, volumes, and their compositions, and they are graphic primitives that represent data. There are dateless number of shapes and they are used for categorization.sizingSize changes in area, length or volume. It influences the way of individual data representation and display.BrightnessBrightness or luminance is good for large interval and continuous data. However, there is a limitation to distinguish among all those different levels of brightness.ColorIt changes according to two parameters, hue and saturation. It requires mapping of data set to individual distort codes.OrientationOrientation changes in alignment. It cannot be used for all marks. For example, circles look the same even their orientations change. Shapes with natural hotshot axis vertebra are the best to apply orientation.TextureIt is a combination of many other visual variables including marks, color, orientation and so on.MotionMotion describes all visual variables change over time and it can convey more inf ormation.Human perceptual experience formationVisual perception means the superpower to interpret and process information from visible illuminate in the adjoin environment. Not everyone perceives data exactly the same. Different smashers differently interpret the identical visual representations.When designing visualization, to reduce the confusion later on, the designers need to take account of color usage of graphical entities for accurate measurement, criterion of distinct entities, and etc. Besides, we also need to consider the primitives that humans ordinarily detect pre-attentively and the level of accuracy we perceive various primitives. Consequently, when we visualize data, it is a basic requirement to learn the limits of human perception since we need to portion in these limitations and avoid producing images with vague or deceptive information.Visual SystemThe human eye is composed of many parts. 5 They obtain visual images, emphasis them accurately and send mess ages to the brain. The main sensory component of vision assembles well-situated scattered from objects and forms a two dimensional function on the photoreceptors, the piffling sensory devices which respond in the presence of photons making up light waves.Information related to the external objects in the environment is captured through the visual system. Light rays from an object enters through the outer part of the eye, named the cornea. It helps the eye to way to make things look sharp and clear. Then, the light rays travel towards an opening called the pupil, the stern round circle in the middle of the aslant part of the eye. The colored eye is called the iris and the pupil is just a hole in the iris. The iris manoeuvers the amount of light goes into the eye. Besides, your eye also possesses a lens system to focus the light rays. Light passes through the lens till the back of the eye, the retina. It has millions of tiny light sensitive cells sending messages to parts of t he brain, the optic nerves. subject field of ViewA pair of normal healthy human look can view about 200 degrees horizontally where approximately one hundred twenty degrees of which are shared by both look and giving rise to whats known as binocular vision. 6 It has a field of view of cxxxv degrees vertically. However, as we get older, these determine decrease. Both of human eyes are positioned more or less on the front of our heads and it is common in prey species as it helps increase an animals total field of view.Angular colonizationAngular resolution refers to the minimum distance at which our eyes can differentiate things of the same size and shape from each other. 6 The typical set of human eyes has an angular resolution of one minute of arc. It means objects one degree apart from each other can be distinguished. Therefore, angular resolution is usable when we need to differentiate similar objects. Nevertheless, every human eye is different and their angular resolution va ries based on eyesight strength, eye shape and age.The Blind SpotThe photoreceptor cells in our eyes are used to perceive light and information being veritable is relayed to the brain via the optic nerve. Blind spot is the visual field where it lacks the light detecting photoreceptor cells on the optic disc of the retina. 6 A small part of the field of vision is not perceived as there are no cells to detect light. Normally, with two eyes, the brain interpolates the blind spot based on surrounding details and information from the other eyes so that the blind spot would not be detected. However, blind spot can be perceived easily with one eye c neglectd.Perceptual treatAttention acts as a critical role in perceiving information. Perception can be pre-attentive or attentive. Usually the hightail it of perceived information starts from the low level pre-attentive towards the high cognitive stages.Professor Treisman states perceptions that can be performed in less than 200 to 250ms ar e regarded as pre-attentive. 7 Initiating random locations of the elements in display by human eyes normally take at least 200ms. That determines attention cannot be pre-focused on any particular view and information is processed in parallel by the human visual system. Pre-attentive perception requires its objects to possess a unique feature, such as color and size.For attentive perception, it uses short term memory and it is selective. Attentive tasks convert unseasonable image effects into a well-structured objects. Attentive perception is generally long-play and often signifies aggregates of what is in the scene.When designing visualization, the designers should take note of pros and cons of the human visual system and provide well-suited visuals to the viewing audience for easy analysis. Thus, in order to use the visual features effectively and not to produce visual interference effects masking information in a display, the visualization creators should be aware of the atten tive tasks and the pre-attentive visual features like length, width, hue, intensity, lighting direction, and so on.selective information installationThe very primary step of visualization is the data to visualise. It is a must to explore and examine the characteristics of the data since it can be from many different kinds of sources and has a wide variety of attributes and features.Data TypesData can be differentiated into two main types no. (numeric values) and nominal (non-numeric values). 2To be specific, ordinal values meanBinary values those with only 0s and 1sDiscrete values integer values from a very particular division persisting real valuesNominal values areCategorical values from list of possibilitiesRanked categorical variables with significant orderingArbitrary infinite range of values without significant orderingScale is other useful technique of sorting data variables since each graphical attribute from raw data possesses denture associated with it. There ar e three attributes of scale parliamentary procedure relation ranked nominal variables and ordinal variables which can be tell in some mannerDistance metric all ordinal variables where the distances of different records can be calculatedExistence of absolute cipher variables with fixed lowest valueData Pre-processingIn reality, real world data that is to be analyzed can be incomplete, noisy, incoherent and cumulative. Those raw data need to be transformed somehow into an understandable format and the process of its transformation is known as data pre-processing. Data pre-processing can greatly improve the quality of data visualization results. There are some different aspects of data pre-processingMetadata and statisticalMissing values and data cleansingNormalizationSegmentationSampling and sub-settingDimension reduction procedure nominal dimensions to numbersAggregation and summarizationSmoothing and filteringRaster to vector conversionFor more information about data pre-proces sing techniques refer to 2.Visualization Techniques for Different Types of DataVisualization techniques will be differed for different types of data since they comprise special characteristics. Main types of data and useful visualization methods for them will be discussed in this section.Spatial DataSpatial attributes identify data in 1,2 or multi dimension. Visualizing spatial data is defined as mapping spatial data to spatial attributes on the screen. 2Techniques of visualization of those data include histograms, linear probes, flow visualization, vector field visualization, slice plus isosurface, isosurface plus glyphs and so on.Geospatial DataGeospatial data or geographic information classifies geographic locations and boundaries in the real world. 8 They include coordinates and topology on earth. Examples of geospatial data consist of climate, environmental, economical and sociological and credit card payment locations.Visualization methods of such data can be completed using d ot maps, pel maps, network maps, choropleth maps and cartograms. 2 variable DataMultivariate data is lists or tables of data that arises from more than one variable. It normally doesnt have an precise spatial attribute. 2Multivariate data can be visualized by point based techniques like scatter-plots and imbibe based methods, line based techniques like graphs, parallel coordinates, andrews curves and radial axis techniques, and region based techniques which are bar charts, histograms and tabular displays. Combination of above techniques are also applied sometimes.Trees, Graphs and NetworkBertin declares that trees, graphs and network visualization demonstrates the relationships of each data recorded, similarities among values and attributes, parent and child nodes, connectedness such as networks between countries around the world, shared classification and derivation. 9Space filling methods, non space filling methods, displaying arbitrary graphs and networks, and node link graphs are some of the methods for trees, graphs and networks visualization. maps, pixel maps, network maps, choropleth maps and cartograms. 2Text and DocumentsBy applying suitable visualization techniques, valuable information can be obtained from grand resources of information such as digital libraries, text files from your computer and billions of words in your thesis paper. Searching comparable with(predicate) patterns and outliers within the text or documents will be painful without visualization. tatter clouds, word trees, text arcs and arc diagrams can be used for visualizing single documents. Visualization practice for collections of documents are self organizing maps, themescapes and document cards. 2Interaction Concepts Techniques butt and his group clarify that interaction within data visualization is a helpful structure for transforming what the users see and how they perceive it. Interactions will transform visualization images to better and smooth transitions. Summary of interaction techniques are discussed as below. 10 navigationIt allows the users to adjust the cameras position and scale the vision. Examples include panning, rotating and zooming.SelectionSelection refers categorizing an object or collections of objects. To be precise, it grants the user to control the regions of interest. Highlighting, deleting and modifying are types of selection.FilteringThe size of data mapped on the screen is reduced by filtering techniques by reducing or omitting dataset, dimensions or both.ReconfiguringIt is to change the way analyzed data is mapped to visualization graphical attributes like reordering data layouts in order to provide a diverse way of viewing data.EncodingUsers are permitted to control graphical attributes such as point size, line colors to discover different features of visualization.ConnectingConnecting means linking different views or objects.Abstracting and ElaboratingIt is to modify the level of detail. hybridizingHybrid defines combini ng the above techniques together.Effective VisualizationIn fact, visualizations implemented by the designers have larger risks of being ineffective than being effective. It is not very simple to build effective visualizations where the users satisfy as there are many chances of data being distorted and lost during the mapping process, or data presented is too confusing and complex for the users to interpret, and so on. A victorious and effective visualization efficiently and accurately transmits the preferred information to the viewers. Therefore, the designers should take in consideration of what the targeted users really want to observe from the results so that they will be able to visualize effectively.Intuitive Data MappingsEd H. chi explains that it is essential to consider the importance of data semantics and the context of the user. 11 To avoid any misinterpretation, the designers should be able to predict the users expectations. Choosing data-to-graphics mappings that prov ides the users mental model will importantly support in interpretation. The designer should take note of the compatibility between scale of data and graphic attributes on the screen. Besides, they should utilize humans abilities to correlate position on the screen medium with position in real world.Selecting and Adjusting ViewsIt is overt that one view is hardly satisfactory to express all the information enclosed in the dataset. Expecting the view modifications which are most useful to the users is one of the major factors of developing an effective visualization. Common view operations are as follows. 2Scrolling and Zooming OperationsThis operation comes in handy when the dataset is too huge to be presented as one whole at the resolution that the viewer wants.Color Map ControlIt allows the user to make changes of individual attribute colors or entire palette.Mapping ControlMapping control helps the viewers to toggle among different ways of visualizing the same data and to discove r the distinct features which might be hidden.Scale ControlThe user can focus on specific data subsets by applying scale control where they can modify the range and distribution of values.Information DensityThe designers decision, to allege how much information to display, plays an important role for an effective visualization and representation. Alexandru 12 points out that if there is too little information to present, it is the best to display the results as text. Conversely, if the data has too much information to present, it might cause confusion, lose essential information within the data, and face with obscurities in interpretation. In such cases, the user should be permitted to disable or enable different components of the presentation.Keys, Labels and Legends nearly of the visualizations are ineffective because they lack useful and supported information to advocate them. 2 Keys, labels and legends are therefore very helpful. Examples include captions, mappings used, grid marks, units of axes, key for symbols, color bar and etc.Using Color with CareColor can add significant visual appeal to a visualization but can also significantly decrease the effectiveness of the communication process. 2 consumption of color is context dependent and the characteristics of dataset itself can influence how the colors are noticeable. The designers should not forget there might be some color blind users as well.The Importance of AestheticsVisuals, with both informative and harming to the eye, are known as the best representations. If the visualization is aesthetically pleasant, it attracts the viewers to analyze it in greater details. 2 Some useful guidelines for attractive visualization designs are as below.FocusThe users attention should be drawn towards the most vital part of the visualization.BalanceBalancing the screen space is another aspect to take note of designing pleasing visualizations. The most important components should be placed in the center.Simplici tyRepresenting too much information will confuse the viewers. The designers should get rid of features which can be aloof without losing information wanted to pass on since it is the best to be as simple as possible.Misleading Visualizationsbc