Exploring multivariate representations of indices along linear geographic features

Abstract

A study of the walkability of a Swiss town required finding suitable representations of multivariate geographical da-ta. The goal was to represent multiple indices of walkability concurrently and visualizing the data along the street network it relates to. Different indices of pedestrian friendliness were assessed for short street sections and then mapped to an overlaid grid. Basic and composite glyphs were designed using square-or triangle-areas to display one to four index values concurrently within the grid structure. Color was used to indicate different indices. Implement-ing visualizations for different combinations of index sets, we find that single values can be emphasized or de-emphasized by selecting the color scheme accordingly and that different color selections either allow perceiving single values or overall trends over the evaluated area. Values for up to four indices can be displayed in combination within the resulting geovisualizations and the underlying gridded road network references the data to its real world locations.

Micro diagrams: visualization of categorical point data from location-based social media

“…The result of the visualization process is a well-organized map that is similar to a cartogram but not distorted, such as with a tile map (McNeill & Hale, 2017), and it can be combined with a reference map. Similar cartographic (Bleisch & Hollenstein, 2017) and visualization approaches (Heimerl et al, 2018) document the related work chapter. The methods chapter describes our contribution of the creation workflow for micro diagrams and the parameters for the visualization that answer research question Q2 about the influencing factors.…”

“…The idea of using smaller diagrams to show the distribution of categories with different data geometries has been the focus of researchers (Ghanem, Magdy, Musleh, Ghani, & Mokbel, 2014;Miller, 2007). The basis for the visualization can be points (Zhou, Tian, Xiong, & Wang, 2016); moving point objects (Andrienko & Andrienko, 2008;Ding, Fan, & Meng, 2015;Scheepens, Van De Wetering, & Van Wijk, 2014); lines (Bleisch & Hollenstein, 2017), such as in Figure 1; or polygons (Jo et al, 2019). Furthermore, a similar technique was introduced for point sets with multiple classes in scatterplots (Heimerl, Chang, Sarikaya, & Gleicher, 2018).…”

Exploratory Bivariate and Multivariate Geovisualizations of a Social Vulnerability Index

“…While the Chernoff face is perhaps the best-known example, Fuchs et al (2017), in their overview of 64 papers that performed controlled studies on different glyph designs, point out that the possibilities for designing glyphs are endless. We adapted our glyph design from Bleisch and Hollenstein (2018), who used square glyphs to simultaneously represent up to four walkability indices in a regular grid.…”

A visual approach to creating multivariate geovisualization test data

“…The four layers are then overlaid and, for pixels at defined intervals, the greyscale values extracted to arrive at a four-dimensional data set covering the street network. The four-dimensional data is visualised using four squares combined to glyphs (see Bleisch & Hollenstein 2017 for details on the glyph design). The data derivation prototype allows applying noise to the extracted data values in case a test setting requires it.…”