Automatic Layout Algorithms Research Articles

Graph Layout Aesthetics in UML Diagrams: User Preferences

The merit of automatic graph layout algorithms is typically judged by their computational eciency and the extent to which they conform to aesthetic criteria (for example, minimising the number of crossings, maximising orthogonality). Experiments investigating the worth of such algorithms from the point of view of human usability can take dierent forms, depending on whether the graph has meaning in the real world, the nature of the usability measurement, and the eect being investigated (algorithms or aesthetics). Previous studies have investigated performance on abstract graphs with respect to both aesthetics and algorithms, nding support for reducing the number of crossings and bends, and increasing the display of symmetry. This paper reports on preference experiments assessing the eect of individual aesthetics in the application domain of UML diagrams. Subjects’ preferences for one diagram over another were collected as quantitative data. Their stated reasons for their choice were collected as qualitative data. Analysis of this data enabled us to produce a priority listing of aesthetics for this domain. These UML preference results reveal a difference in aesthetic priority from those of previous domain-independent experiments.

Effective information visualisation: a study of graph drawing aesthetics and algorithms

Information visualisation systems which generate diagrams representing discrete relational information must consider potential users if they are to be effective. Many algorithms which render an abstract graph structure as a diagram are valued for their conformance to aesthetic criteria (e.g. reducing the number of edge crossings, maximising symmetry), or for computational efficiency. They are not usually judged on their ability to produce diagrams that maximise human performance. This paper presents the results of experiments investigating the relative worth (from an HCI point of view) of graph drawing aesthetics and algorithms using a single graph. The results indicate that while some individual aesthetics affect human performance, it is difficult to say that one algorithm is ‘better’ than another from a relational understanding point of view. Designers of automatic layout algorithms, and the systems which embody such algorithms, can benefit from this study and this human-centred approach, by adapting their methods to focus on user concerns, rather than computational ones.

Parametric graph drawing

A diagram is a drawing on the plane that represents a graph like structure, where nodes are represented by symbols and edges are represented by curves connecting pairs of symbols. An automatic layout facility is a tool that receives as input a graph like structure and is able to produce a diagram that nicely represents such a structure. Many systems use diagrams in the interaction with the users; thus, automatic layout facilities and algorithms for graphs layout have been extensively studied in the last years. We present a new approach in designing an automatic layout facility. Our approach is based on a modular management of a large collection of algorithms and on a strategy that, given the requirements of an application, selects a suitable algorithm for such requirements. The proposed approach has been used for designing the automatic layout facility of Diagram Server, a network server that offers to its clients several facilities for managing diagrams.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Development of a Commercial Made‐to‐Measure Garment Pattern System

Describes a PC‐based CAD system for producing made‐to‐measure garment patterns which has been developed and implemented in the commercial environment of a bridalwear manufacturer. The software simulates the hand drafting methods of the company while automating pattern production with the following benefits: first, very rapid production of made‐to measure patterns; second, production of patterns which require minimal alteration at first fitting; third, a user friendly interface with very short training period; fourth, the de‐skilling of the pattern cutting procedure so that problems of staff turnover and training are minimal; and fifth, the elimination of human error in pattern cutting. Initial software development concentrated on bodice patterns. Further enhancements included sleeves and skirts and the mixing and matching of these three components of a dress. Cutting layouts were produced using automatic layout algorithms so that the whole procedure from order and measurements entry through pattern drafting and lay‐planning to the final full scale plotting could be carried out automatically. Furthermore, a queuing system allowed several orders previously entered on the computer to be processed in succession without any intervention by an operator. All the company’s styles are now held by the computer, which is in constant use, to the exclusion of the previously used skilled and lengthy hand drafting methods.

Dynamic graph drawing (abstract)

An automatic layout facility is a tool that receives as input a graph-like structure and is able to produce a diagram that nicely represents such a structure. Because of the increasing number of systems that manage diagrams, automatic layout facilities and algorithms for graphs layout have been extensively studied in the last years. We present a new approach in designing an automatic layout facility. Our approach is based on a modular management of a collection of algorithms and on a tool that is able to automatically select the best algorithm for a given application. Such approach has been used for devising the automatic layout facility of Diagram Server, a network server that offers to its clients several facilities for managing diagrams. (Joint work with P. Bertolazzi and G. Di Battista.)

Edge: An extendible graph editor

EDGE is an editor kernel for the direct and visual manipulation of graphs. The kernel can be adapted quickly to diverse applications based on graphs, such as PERT chart editing, directory browsing, call graph display, logic circuit simulation or configuration visualization. EDGE provides potential solutions to the following general problems faced by any graph editor. (1) Automatic graph layout: how can application-specific layout requirements, individual preferences, and layout stability be integrated with automatic layout algorithms? EDGE solves this problem with a novel algorithm that is based on layout constraints. (2) Graph abstraction: how can users deal with large graphs containing hundreds of nodes and edges, and thousands of edge crossings? EDGE can reduce the apparent complexity with subgraph abstractions and a novel clustering technique called edge concentration. (3) Adaptability: how should the editor kernel be structured to be adaptable to various applications? EDGE uses a special graph representation language for specifying visual appearance and the inheritance mechanism of C++ to achieve extendibility. (4) Persistence of graphs: how can the graph structures produced by the editor be kept in long-term storage, especially if the node and edge data structures have been extended for a particular application? Our approach uses a standardized, external format for graphs and handles extensions with program generator technology: the I/O routines for reading and writing extended node and edge data structures are produced automatically from the declarations of these data structures. This paper describes EDGE and presents details of the above solutions.