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36
personal communication
, 1997
"... these abstracts from the Eighteenth Annual Scientific Meeting may not present completed work nor were they formally peerreviewed for technical content. Individuals wishing to reference or quote from these abstracts in whole or part should obtain the author's permission. Abstracts were opticall ..."
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these abstracts from the Eighteenth Annual Scientific Meeting may not present completed work nor were they formally peerreviewed for technical content. Individuals wishing to reference or quote from these abstracts in whole or part should obtain the author's permission. Abstracts were optically scanned and then edited for entry into this compilation. But since the process is not perfect, errors may have been introduced, for which we apologize.
Dynamic Map Labeling
, 2006
"... We address the problem of filtering, selecting and placing labels on a dynamic map, which is characterized by continuous zooming and panning capabilities. This consists of two interrelated issues. The first is to avoid label popping and other artifacts that cause confusion and interrupt navigation, ..."
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We address the problem of filtering, selecting and placing labels on a dynamic map, which is characterized by continuous zooming and panning capabilities. This consists of two interrelated issues. The first is to avoid label popping and other artifacts that cause confusion and interrupt navigation, and the second is to label at interactive speed. In most formulations the static map labeling problem is NPhard, and a fast approximation might have O(nlogn) complexity. Even this is too slow during interaction, when the number of labels shown can be several orders of magnitude less than the number in the map. In this paper we introduce a set of desiderata for “consistent ” dynamic map labeling, which has qualities desirable for navigation. We develop a new framework for dynamic labeling that achieves the desiderata and allows for fast interactive display by moving all of the selection and placement decisions into the preprocessing phase. This framework is general enough to accommodate a variety of selection and placement algorithms. It does not appear possible to achieve our desiderata using previous frameworks. Prior to this paper, there were no formal models of dynamic maps or of dynamic labels; our paper introduces both. We formulate a general optimization problem for dynamic map labeling and give a solution to a simple version of the problem. The simple version is based on label priorities and a versatile and intuitive class of dynamic label placements we call “invariant point placements”. Despite these restrictions, our approach gives a useful and practical solution. Our implementation is incorporated into the GVis system which is a fulldetail dynamic map of the continental USA. This demo is available through any browser.
Metrics for Functional and Aesthetic Label Layouts
 In 5th Int. Symp. on Smart Graphics
, 2005
"... Abstract. Coreferential relations between textual and visual elements in illustrations can be encoded efficiently through textual labels. The labels support students to learn unknown terms and focus their attention on important aspects of the illustration; while a functional and aesthetic label lay ..."
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Abstract. Coreferential relations between textual and visual elements in illustrations can be encoded efficiently through textual labels. The labels support students to learn unknown terms and focus their attention on important aspects of the illustration; while a functional and aesthetic label layout aims at guaranteeing the readability of text strokes as well as preventing the referential mismatches. By analyzing a corpus of complex label layouts in handdrawn illustrations, a classification of label layout styles and several metrics for functional requirements and aesthetic attributes were extracted. As the choice of a specific layout style seems largely determined by individual preferences, a realtime layout algorithm for internal and external labels balances conflicting userspecific requirements, functional and aesthetic attributes. 1
Boundary labeling with octilinear leaders
 Algorithmica
, 2010
"... Abstract. Amajor factor affecting the readability of an illustration that contains textual labels is the degree to which the labels obscure graphical features of the illustration as a result of spatial overlaps. Boundary labeling addresses this problem by attaching the labels to the boundary of a r ..."
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Abstract. Amajor factor affecting the readability of an illustration that contains textual labels is the degree to which the labels obscure graphical features of the illustration as a result of spatial overlaps. Boundary labeling addresses this problem by attaching the labels to the boundary of a rectangle that contains all features. Then, each feature should be connected to its associated label through a polygonal line, called leader, such that no two leaders intersect. In this paper we study the boundary labeling problem along a new line of research, according to which different pairs of type leaders (i.e. do and pd, od and pd) are combined to produce boundary labelings. Thus, we are able to overcome the problem that there might be no feasible solution when labels are placed on different sides and only one type of leaders is allowed. Our main contribution is a new algorithm for solving the total leader length minimization problem (i.e., the problem of finding a crossing free boundary labeling, such that the total leader length is minimized) assuming labels of uniform size. We also present an NPcompleteness result for the case where the labels are of arbitrary size. 1
Manytoone boundary labeling
 In Proc. Asia Pacific Symposium on Information Visualisation (APVIS2007), IEEE
, 2007
"... In boundary labeling, each point site is uniquely connected to a label placed on the boundary of an enclosing rectangle by a leader, which may be a rectilinear or straight line segment. To our knowledge, all the results reported in the literature for boundary labeling deal with the socalled oneto ..."
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Cited by 8 (4 self)
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In boundary labeling, each point site is uniquely connected to a label placed on the boundary of an enclosing rectangle by a leader, which may be a rectilinear or straight line segment. To our knowledge, all the results reported in the literature for boundary labeling deal with the socalled onetoone boundary labeling, i.e., different sites are labelled differently. In certain applications of boundary labeling, however, more than one site may be required to be connected to a common label. In this case, the presence of crossings among leaders often becomes inevitable. Minimizing the total number of crossings in boundary labeling becomes a critical design issue as crossing is often regarded as the main source of confusion in visualization. In this paper, we consider the crossing minimization problem for multisitetoonelabel boundary labeling, i.e., finding the placements of labels and leaders such that the total number of crossings among leaders is minimized. We show the crossing minimization problem to be NPcomplete under certain oneside and twoside labeling schemes. Subsequently, approximation algorithms or heuristics are derived for the above intractable problems.
Boundary labelling of optimal total leader length
 10th Panhellenic Conference on Informatics (PCI'05
, 2005
"... Abstract. In this paper, we consider the leader length minimization problem for boundary labelling, i.e. the problem of finding a legal leaderlabel placement, such that the total leader length is minimized. We present an O(n 2 log 3 n) algorithm assuming typeopo leaders (rectilinear lines with eit ..."
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Cited by 8 (6 self)
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Abstract. In this paper, we consider the leader length minimization problem for boundary labelling, i.e. the problem of finding a legal leaderlabel placement, such that the total leader length is minimized. We present an O(n 2 log 3 n) algorithm assuming typeopo leaders (rectilinear lines with either zero or two bends) and labels of uniform size which can be attached to all four sides of rectangle R. Our algorithm supports fixed and sliding ports, i.e., the point where each leader is connected to the label (referred to as port) may be fixed or may slide along a label edge.
AgentBased Annotation of Interactive 3D Visualizations
 6 th International Symposium on Smart Graphics. SpringerVerlag (in print
, 2006
"... Abstract. This paper presents a novel realtime algorithm to integrate internal and external labels of arbitrary size into 3D visualizations. Moreover, comprehensive dynamic content can be displayed in annotation boxes. Our system employs multiple metrics in order to achieve an effective and aesthet ..."
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Abstract. This paper presents a novel realtime algorithm to integrate internal and external labels of arbitrary size into 3D visualizations. Moreover, comprehensive dynamic content can be displayed in annotation boxes. Our system employs multiple metrics in order to achieve an effective and aesthetic label layout with adjustable weights. The layout algorithm employs several heuristics to reduce the search space of a complex layout task. Initial layouts are refined by label agents, i.e., local strategies to optimize the layout and to minimize the flow of layout elements in subsequent frames. 1
A ZoneBased Approach for Placing Annotation Labels on Metro Maps
"... Abstract. Handdrawn metro map illustrations often employ both internal and external labels in a way that they can assign enough information such as textual and image annotations to each landmark. Nonetheless, automatically tailoring the aesthetic layout of both textual and image labels together is ..."
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Cited by 6 (2 self)
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Abstract. Handdrawn metro map illustrations often employ both internal and external labels in a way that they can assign enough information such as textual and image annotations to each landmark. Nonetheless, automatically tailoring the aesthetic layout of both textual and image labels together is still a challenging task, due to the complicated shape of the labeling space available around the metro network. In this paper, we present a zonebased approach for placing such annotation labels so that we can fully enhance the aesthetic criteria of the label arrangement. Our algorithm begins by decomposing the map domain into three different zones where we can limit the position of each label according to its type. The optimal positions of labels of each type are evaluated by referring to the zone segmentation over the map. Finally, a new geneticbased approach is introduced to compute the optimal layout of such annotation labels, where the order in which the labels are embedded into the map is improved through the evolutional computation algorithm. We also equipped a semantic zoom functionality, so that we can freely change the position and scale of the metro map. 1
A Smart Algorithm for Column Chart Labeling
 IN 5TH INT. SYMP. ON SMART GRAPHICS
, 2005
"... This paper presents a smart algorithm for labeling column charts and their derivatives. To efficiently solve the problem, we separate it into two subproblems. We first present a geometric algorithm to solve the problem of finding a good labeling for the labels of a single column, given that some ot ..."
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Cited by 5 (0 self)
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This paper presents a smart algorithm for labeling column charts and their derivatives. To efficiently solve the problem, we separate it into two subproblems. We first present a geometric algorithm to solve the problem of finding a good labeling for the labels of a single column, given that some other columns have already been labeled. We then present a strategy for finding a good order in which columns should be labeled, which repeatedly uses the first algorithm for some limited lookahead. The presented algorithm is being used in a commercial product to label charts, and has shown in practice to produce satisfactory results.
Algorithms for Multicriteria OneSided Boundary Labeling
 Proc. 15th Int. Symp. Graph Drawing (GD’07
, 2007
"... Abstract. We present new algorithms for labeling a set P of n points in the plane with labels that are aligned to the left of the bounding box of P. The points are connected to their labels by curves (leaders) that consist of two segments: a horizontal segment, and a second segment at a fixed angle ..."
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Abstract. We present new algorithms for labeling a set P of n points in the plane with labels that are aligned to the left of the bounding box of P. The points are connected to their labels by curves (leaders) that consist of two segments: a horizontal segment, and a second segment at a fixed angle with the first. Our algorithm finds a collection of nonintersecting leaders that minimizes the total number of bends, the total length, or any other ‘badness ’ function of the leaders. An experimental evaluation of the performance is included. 1