1,721,280 research outputs found
Give chance a chance: modeling density to enhance scatter plot quality through random data sampling
No full textThe problem of visualizing huge amounts of data is well known in Infor- mation Visualization. Dealing with a large number of items forces almost any kind of Infovis technique to reveal its limits in terms of expressivity and scalability. In this paper we focus on 2D scatter plots, proposing a "feature preservation" approach, based on the idea of modeling the visu- alization in a virtual space in order to analyze its features (e.g, absolute density, relative density, etc.). In this way we provide a formal framework to measure the visual overlapping, obtaining precise quality metrics about the visualization degradation and devising automatic sampling strategies able to improve the overall image quality. Metrics and algorithms have been improved through suitable user studies
Improving 2D scatterplots effectiveness through sampling, displacement, and user perception
No full textIn this paper we present a novel, hybrid, and automatic strategy whose goal is to reduce the 2D scatter plot cluttering. The presented technique relies on a combination of non uniform sampling and pixel displacement and it is driven by perceptual results coming from a suitable user study. The same results are used to define precise quality metrics that allow for validating our approach. © 2005 IEEE
Is it darker? Improving density representation in 2D scatter plots through a user study
No full textDensity differences are one of the main features users perceive in 2D scatter plots. However, because of pixels' collisions, some areas become saturated and such differences are lost. To solve this problem, several proposals rely on sampling the dataset before visualizing it. Some of these introduce precise measures to understand the image degradation and use numerical differences in pixels to estimate density differences. It is our opinion that this issue deserves a deeper analysis, taking into account perceptual issues. In this paper we describe a study we conducted to understand the relationship between numerical pixel density and the perceived density. The results obtained were used to refine a sampling technique we developed to preserve relative densities in the context of 2D scatter plots
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Reducing InfoVis cluttering through non uniform sampling, displacement, and user perception
No full textClutter affects almost any kind of visual technique and can obscure the structure present in the data even in small datasets, making it hard for users to find patterns and reveal relationships. In this paper we present a general strategy to analyze and reduce clutter using a special kind of sampling, together with an ad-hoc displacement technique and perceptual issues collected through a user study. The method, defined for 2D scatter plots, is flexible enough to be used in quite different contexts. In particular, in this paper we prove its usefulness against scatter plot, radviz, and parallel coordinates visualizations. © 2006 SPIE-IS&T
Springview: Cooperation of radviz and parallel coordinates for view optimization and clutter reduction
No full textIn this paper we integrate radviz and parallel coordinates, two methods able to handle multidimensional datasets, exploiting their contrasting characteristics. From on side radviz offers good direct data manipulation (i.e., brushing) techniques and low cluttering but it fails in providing visualization of quantitative information; conversely, parallel coordinates clearly shows the values of data attributes and their ranges but suffers from high cluttering also on small datasets and presents tedious manipulation techniques. We developed a prototype, called SpringView, that allows for simultaneously viewing both radviz and parallel coordinates and implements several useful techniques to manipulate the data, both interactively and, more interestingly, automatically. We challenged our approach against two well know multidimensional datasets, proving its effectiveness
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
See what you know: analyzing data distribution to improve density map visualization
No full textDensity maps allow for visually rendering density differences, usually mapping density values to a grey or color scale. The paper analyzes the drawbacks arising from the commonly used mapping strategies and introduces a novel technique able to improve the overall mapping process, presenting the user with an increased number of visual density differences. The proposed technique is driven by statistical knowledge about the density distribution and a set of quality metrics allows for validating, in an objective way, its effectiveness
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