Graph (mathematics) The edges may be directed or undirected. For example, if the vertices represent people at a party, and there is an edge between two people if they shake hands, then this is an undirected graph, because if person A shook hands with person B, then person B also shook hands with person A. In contrast, if there is an edge from person A to person B when person A knows of person B, then this graph is directed, because knowledge of someone is not necessarily a symmetric relation (that is, one person knowing another person does not necessarily imply the reverse; for example, many fans may know of a celebrity, but the celebrity is unlikely to know of all their fans). This latter type of graph is called a directed graph and the edges are called directed edges or arcs.
Vertices are also called nodes or points, and edges are also called arcs or lines. Graphs are the basic subject studied by graph theory. Definitions in graph theory vary. (the number of vertices). A directed graph. where to. Information visualization. Graphic representation of a minute fraction of the WWW, demonstrating hyperlinks Information visualization or information visualisation is the study of (interactive) visual representations of abstract data to reinforce human cognition. The abstract data include both numerical and non-numerical data, such as text and geographic information. However, information visualization differs from scientific visualization: "it’s infovis [information visualization] when the spatial representation is chosen, and it’s scivis [scientific visualization] when the spatial representation is given".[1] Overview[edit] Partial map of the Internet early 2005, each line represents two IP addresses, and some delay between those two nodes.
The field of information visualization has emerged "from research in human-computer interaction, computer science, graphics, visual design, psychology, and business methods. Data analysis is an indispensable part of all applied research and problem solving in industry. Stuart K. JESS3 / The State of The Internet. Introduction to Circos, Features and Uses // CIRCOS Circular Genome Data Visualization. The Shape of Song. Thinkmap Visual Thesaurus - An online thesaurus and dictionary of over 145,000 words that you explore using an interactive map. AmCharts: JavaScript/HTML5 charts. Nutrient Contents - Parallel Coordinates.
Future - Science & Environment - Drake equation: How many alien civilizations exist? Are we alone? It is a question that has occupied mankind for centuries. Today, we live in an age of exploration, where robots on Mars and planet-hunting telescopes are beginning to allow us to edge closer to an answer.
While we wait to establish contact, one technique we can use back on Earth is an equation that American astronomer Frank Drake formulated in the 1960s to calculate the number of detectable extraterrestrial civilizations may exist in the Milky Way galaxy. It is not a rigorous equation, offering a wide range of possible answers. Instead it is more a tool used to help understand how many worlds might be out there and how those estimates change as missions like Kepler, a telescope that is currently searching for Earth-like planets, begin to discover more about our universe. Voyage - RSS feed reader. Where America Lives. Wordle - Beautiful Word Clouds. Diagram. A diagram is a two-dimensional geometric symbolic representation of information according to some visualization technique.
Sometimes, the technique uses a three-dimensional visualization which is then projected onto the two-dimensional surface. The word graph is sometimes used as a synonym for diagram. Overview[edit] The term diagram in common sense can have a general or specific meaning: In the specific sense diagrams and charts contrast computer graphics, technical illustrations, infographics, maps, and technical drawings, by showing "abstract rather than literal representations of information".[1] The essences of a diagram can be seen as:[1] a form of visual formatting devicesa display that do not show quantitative data or [numerical], but rather relationships and abstract informationwith building blocks such as geometrical shapes connected by lines, arrows, or other visual links.
Main diagram types[edit] There are at least the following types of diagrams: Specific diagram types[edit] Flowchart. A simple flowchart representing a process for dealing with a non-functioning lamp. A flowchart is a type of diagram that represents an algorithm, workflow or process, showing the steps as boxes of various kinds, and their order by connecting them with arrows. This diagrammatic representation illustrates a solution to a given problem. Flowcharts are used in analyzing, designing, documenting or managing a process or program in various fields.[1] Overview[edit] Flowcharts are used in designing and documenting complex processes or programs.
A processing step, usually called activity, and denoted as a rectangular boxa decision, usually denoted as a diamond. A flowchart is described as "cross-functional" when the page is divided into different swimlanes describing the control of different organizational units. Flowcharts depict certain aspects of processes and they are usually complemented by other types of diagram. History[edit] Flowchart building blocks[edit] Examples[edit] Symbols[edit] Arrows. Pie chart. Pie chart of populations of English native speakers Pie charts are very widely used in the business world and the mass media.[3] However, they have been criticized,[4] and many experts recommend avoiding them,[5][6][7][8] pointing out that research has shown it is difficult to compare different sections of a given pie chart, or to compare data across different pie charts. Pie charts can be replaced in most cases by other plots such as the bar chart. Example[edit] A pie chart for the example data.
The following example chart is based on preliminary results of the election for the European Parliament in 2004. The table lists the number of seats allocated to each party group, along with the derived percentage of the total that they each make up. The values in the last column, the derived central angle of each sector, is found by multiplying the percentage by 360°. *Because of rounding, these totals do not add up to 100 and 360. Use, effectiveness and visual perception[edit] Spie chart[edit] Radial tree. Example of a radial tree, from a 1924 organization chart that emphasizes a central authority.[1] Radial vs. triangular tree layout Comparison to other layouts[edit] In a simple case, the first node is at the top, and the linked nodes are beneath. As each node typically has more than one child, the resulting shape is relatively triangular. Since the length of each orbit increases with the radius, there tends to be more room for the nodes.
Basic layout[edit] The overall distance "d" is the distance between levels of the graph. The layout has some similarities to a hyperbolic tree, though a key difference is that hyperbolic trees are based on hyperbolic geometry, whereas in a radial tree the distance between orbits is relatively linear. Examples[edit] MindManager and MindMapper are mindmapping systems, which can make radial-like layouts, though are not radial beyond the 2nd level.SpicyNodes is an approach to visualizing hierarchies, which allows moving from node to node. References[edit]