@article {17312,
	title = {Ordered and quantum treemaps: Making effective use of 2D space to display hierarchies},
	journal = {ACM Transactions on Graphics (TOG)},
	volume = {21},
	year = {2002},
	month = {2002/10//},
	pages = {833 - 854},
	abstract = {Treemaps, a space-filling method for visualizing large hierarchical data sets, are receiving increasing attention. Several algorithms have been previously proposed to create more useful displays by controlling the aspect ratios of the rectangles that make up a treemap. While these algorithms do improve visibility of small items in a single layout, they introduce instability over time in the display of dynamically changing data, fail to preserve order of the underlying data, and create layouts that are difficult to visually search. In addition, continuous treemap algorithms are not suitable for displaying fixed-sized objects within them, such as images.This paper introduces a new "strip" treemap algorithm which addresses these shortcomings, and analyzes other "pivot" algorithms we recently developed showing the trade-offs between them. These ordered treemap algorithms ensure that items near each other in the given order will be near each other in the treemap layout. Using experimental evidence from Monte Carlo trials and from actual stock market data, we show that, compared to other layout algorithms, ordered treemaps are more stable, while maintaining relatively favorable aspect ratios of the constituent rectangles. A user study with 20 participants clarifies the human performance benefits of the new algorithms. Finally, we present quantum treemap algorithms, which modify the layout of the continuous treemap algorithms to generate rectangles that are integral multiples of an input object size. The quantum treemap algorithm has been applied to PhotoMesa, an application that supports browsing of large numbers of images.},
	keywords = {hierarchies, Human-computer interaction, image browsers, Information Visualization, jazz, ordered treemaps, treemaps, TREES, zoomable user interfaces (ZUIs).},
	isbn = {0730-0301},
	doi = {10.1145/571647.571649},
	url = {http://doi.acm.org/10.1145/571647.571649},
	author = {Bederson, Benjamin B. and Shneiderman, Ben and Wattenberg,Martin}
}
@article {16970,
	title = {An exploratory evaluation of three interfaces for browsing large hierarchical tables of contents},
	journal = {ACM Trans. Inf. Syst.},
	volume = {12},
	year = {1994},
	month = {1994/10//},
	pages = {383 - 406},
	abstract = {Three different interfaces were used to browse a large (1296 items) table of contents. A fully expanded stable interface, expand/contract interface, and multipane interface were studied in a between-groups experiment with 41 novice participants. Nine timed fact retrieval tasks were performed; each task is analyzed and discussed separately. We found that both the expand/contract and multipane interfaces produced significantly faster times than the stable interface for many tasks using this large hierarchy; other advantages of the expand/contract and multipane interfaces over the stable interface are discussed. The animation characteristics of the expand/contract interface appear to play a major role. Refinements to the multipane and expand/contract interfaces are suggested. A predictive model for measuring navigation effort of each interface is presented.},
	keywords = {Browsing, hierarchies, table of contents, User interfaces},
	isbn = {1046-8188},
	doi = {10.1145/185462.185483},
	url = {http://doi.acm.org/10.1145/185462.185483},
	author = {Chimera,Richard and Shneiderman, Ben}
}
@article {17382,
	title = {Structural analysis of hypertexts: identifying hierarchies and useful metrics},
	journal = {ACM Transactions on Information Systems},
	volume = {10},
	year = {1992},
	month = {1992/04//},
	pages = {142 - 180},
	abstract = {Hypertext users often suffer from the {\textquotedblleft}lost in hyperspace{\textquotedblright} problem: disorientation from too many jumps while traversing a complex network. One solution to this problem is improved authoring to create more comprehensible structures. This paper proposes several authoring tools, based on hypertext structure analysis.In many hypertext systems authors are encouraged to create hierarchical structures, but when writing, the hierarchy is lost because of the inclusion of cross-reference links. The first part of this paper looks at ways of recovering lost hierarchies and finding new ones, offering authors different views of the same hypertext. The second part helps authors by identifying properties of the hypertext document. Multiple metrics are developed including compactness and stratum. Compactness indicates the intrinsic connectedness of the hypertext, and stratum reveals to what degree the hypertext is organized so that some nodes must be read before others.
Several existing hypertexts are used to illustrate the benefits of each technique. The collection of techniques provides a multifaceted view of the hypertext, which should allow authors to reduce undesired structural complexity and create documents that readers can traverse more easily.
},
	keywords = {graph theory, hierarchies, hypertext, metrics, structural analysis},
	isbn = {1046-8188},
	doi = {10.1145/146802.146826},
	url = {http://doi.acm.org/10.1145/146802.146826},
	author = {Botafogo,Rodrigo A. and Rivlin,Ehud and Shneiderman, Ben}
}
