Essay: Graph Visualization Review Paper For Graphics.

Graph Visualization definition and related issues

Discuss aboit the Graph Visualization Review Paper for Graphics.

The review is done on the article “Graph Visualization and Navigation in Information Visualization: A Survey”. The review is done mainly to study briefly about Graph Visualization in Information Visualization. The main issue that is related with Graph Visualization is reviewed from the article and different layouts of Graph Visualization (Herman, Melançon, and Marshall 2000). The technical approach of Graph Visualization is done and their pros and cons in terms of computational cost, aesthetics rules and process of human recognition are reviewed from the article and the navigation techniques Graph Visualization is also reviewed.

Information Visualization gets great advantage from Graph Visualization. Transforming some information into a graphical representation makes the data more highlighting and accurate. The process by which structural information can be transformed into diagram is known as Graph Visualization. In computer system, Graph Visualization is considered as file hierarchy.

There are issues to represent structured into graphs or diagrams. The main issue that arises from Graph Visualization is the difficult to view the diagram. Large diagrams are difficult to manage and study. To view such a large diagram is time taking and gives rise to many issues. In large graphical diagrams, identifying and displaying the layouts is done correctly but problem arises with the usability which makes it difficult to make a difference between nodes and edges. On the other hand, there is a different view for graphs that are small sized. Small size graphs are easy to comprehend and handle. Large graph shows all the detail structure of data but are difficult to comprehend. So the main issue lies in the comprehension process of Graph Visualization that has larger images. To detail the data in small images are easier but most of the graph comes as large images which creates an issue for comprehension.

Mainly four layouts of Graph Visualization are described in the article. The four categories of Graph Visualization are spanning tree layout, horizontal tree layout, classical tree layout and spanning tree layout. The four layout of Graph Visualization can be categorized under three sections. The sections are classical or traditional section, tree spanning section and horizontal 3-D section. The elements that are present in the traditional section of layout have elements like H-Tree, balloon layout and radial layout. The first three layouts that is used for information visualization are categorized mainly into traditional form. The three layout of Graph Visualization are applicable as less or non hierarchical due to which they can also be defined as classical ones. Comparing traditional layout with the spanning tree layout, spanning tree is considered as most important layout of tree. There is a main reason for which 3-D layout and the hyperbolic layout of the tree structure is combined together. The reason behind this is that with the help of 3-D graphing, the layout of hyperbolic tree represents the data in a proper way.

Tree layouts of Graph Visualization and their categories

The main feature that is related with technical aspect of traditional tree layout is that it has ability to depict the structural data in top-down approach. There is also an ability to show the data in left to right tree layout. The data that is structural in Graph Visualization are presented as a grid like structure. This helps to draw the image as a hierarchical manner that has less impact. The technical feature that lies behind the spanning tree layout is that all the nodes of the graph are used by spanning trees to get a view of the data properly. To visit the nodes of the graph by the process of BFS (Breadth First Search) and collecting all the edges of the graph for forming a tree is used for making a spanning tree. There also lies a technical feature in hyperbolic tree approach. The hyperbolic tree approach uses 3-D technology for showing the data as a tree layout. Not only 3-D technology is viewed by hyperbolic tree, also 2-D technology can be viewed by hyperbolic tree. Interaction in the mind is used in hyperbolic tree for representing the data.

The main benefit of traditional tree layout is the data which is visualized in intrinsic hierarchy is reflected by its help. To visualize the data in different layout, small size of graphs are made in traditional layout. The classical tree presentation layout also makes exploration of graphs easier with less hierarchical way. The main existing drawback of traditional tree layout approach is that the structure of the given data is difficult to recognize. Testing is required in traditional approach. Testing process includes examining several planetary o nodes which creates an issue in the traditional approach. In terms of aesthetic rules and also human cognition, the approach of traditional tree layout builds a problem. In terms of computation cost and space utilization it gives an advantage in its efficiency.

The benefit of using spanning tree layout approach is that it uses less size structural data for Graph Visualization. All the nodes of the graph that are made from the real graph are used in the spanning tree. To bring different layout with different weight of same graph, different weight functions are used b y spanning trees. 3-D visualization is used in spanning tree approach. The disadvantage of spanning tree is that it creates a problem in graph visualizing. The problem is that the edges and nodes of a graph collude with one other in 3-D visualization setting. The conclusion that arises is that spanning tree approach of Graph Visualization gives an advantage to aesthetic rules, space utilization and computing cost, but it creates a disadvantage for human cognition.

Main Technical features of each approach

The advantage of layout of hyperbolic tree is that it helps to create the distorted view of image. Moreover, the images that are distorted help to view applications in real life mainly for large trees. The disadvantage of hyperbolic tree layout approach in Graph Visualization is that it is difficult to know the layout because it has very complex background and is mysterious. Space utilization is an advantage with hyperbolic tree approach, but it pays a disadvantage in other aspects such as human cognition, computing cost and aesthetic rules.

Three types of navigation techniques are studied in this article. The techniques are zoom and pan technique, focus and context technique and the incremental exploration technique. The three techniques that are identified can be categorized by navigation techniques. From the review of the navigation techniques, the categorization can be done mainly in the context and focus technique. The reasons for making the categorization intact are that it helps to categorize all the techniques clearly. This article shows all the categorization better. The technique of zoom and pan help to navigate a given graph in semantic and geometric way. The technique of context and focus navigates the graph in clear context. In incremental navigation, images are displayed which makes this navigation as one of the most important navigation technique in Graph Visualization.

The technical feature that arises in zoom and pan navigation techniques is that by the process of semantic zooming and geometric zooming, large images can be explored. The screen contents in Zoom and pan technique is re-adjusted and the screen can also be adjusted. The technical problem with context and focus technique is that the technique of zoom and pan is more complimented in this technique which makes it more useful. The contents of web based are adjusted in the incremental technique which provides as the main technical feature.

The benefit of zoom and pan technique is that by the process of semantic zooming and geometric zooming, large images can be explored in this technique. The geometric technique blows up content of the graph but the screen resolution is adjusted with semantic technique and gives a clear picture. The disadvantage of zoom and pan technique is that problem arises mainly in contextual loss of data and as well as usability. The images are changed totally and credible situations are created via real time response. The real time response, human cognition process and computational cost favor zoom and pan technique.

In context and focus techniques, the advantage is that the focus+context techniques enhances the zoom+pan technique. Focus on objects which need more detailing in zoom+pan techniques are concerned in context and focus technique. The disadvantage of this technique is that it uses general curve to focus on objects which are not focused by standard graphic system. Real time response is an advantage and computational cost and human cognition is a disadvantage in this technique.

The advantage of incremental navigation technique is that it allows the user to focus only on a single part of large graph and other parts can also be focused and zoomed when there is a need. The problem that arises in incremental navigation technique is that if the algorithm that is used for single frame is not same, problem such as saturation of image content arises.

Conclusion:

The review that is done from the article gives a clear view of Graph Visualization and their related issues. The navigation techniques of data visualization are described. To display structural data in image form, no other technique other than graph visualization is better. The four tree layouts of Graph Visualization are described and the tree layouts are further categorized. The advantage and the disadvantages of the tree layout and the navigations techniques are also reviewed from the article.

References:

Herman, I., Melançon, G. and Marshall, M.S., 2000. Graph visualization and navigation in information visualization: A survey. IEEE Transactions on visualization and computer graphics, 6(1), pp.24-43.