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Cartographica
Volume 49, Number 4, Winter 2014
This issue contains:
The Effects of Grid Line Separation in Topographic Maps for Object Location Memory
Dennis Edler, Frank Dickmann, Anne-Kathrin Bestgen and Lars Kuchinke
Research from the field of cognitive psychology provides evidence that cognitive representations of space based on maps or map-like sketches are subject to systematic distortion tendencies. These distortions influence the orientation capacity as they represent errors in spatial memory. Map grids are a traditional feature of map graphics that has rarely been considered in research on spatial distortions in cognitive maps. Grids traditionally assist the map reader in finding coordinates and objects, but they also provide a systematic and homogeneous structure for dividing up map information into smaller units supporting perception and spatial memory. In a previous study it was shown that grids improve object location memory. The aim of this study was to determine whether different sizes of grid cells have an effect on the quality of object location memory. Therefore, an empirical study including the test performances of 33 participants was carried out: the memory performance was measured as both the percentage of correctly recalled object locations (hit rate) and the mean distance errors of correctly recalled objects (spatial accuracy). Three different intervals of grid line spacing (Separation) were applied to topographic maps. These maps varied in their type of characteristic geographical areas, accompanied by three different levels of map complexity (Landscape). The results of this study show that both factors have an impact on object location memory in topographic maps. DOI: 10.3138/carto.49.4.2674
Visual Acceptance of Library-Generated CityGML LOD3 Building Models
Ryan Garnett, Jason T. Freeburn
The acceptance of 3D building models is critical to all urban 3D visualization projects. Building models that are identified as unacceptable can increase the cost of the project, delay the delivery, and, in some cases, cancel the acceptance of the entire project. A 3D modelling approach of using representative textures and geometry rather than actual photorealistic textures and geometry was conducted to determine whether participants who frequent the building multiple times a week over a period of a year would be able to identify the visual difference. Three focus groups were established and used to evaluate the visual quality of the 3D building models. Participants were asked to rank the visual quality of the building, as well as identifying any geometry, texture, or overall visual quality problems. The participants from the three focus groups did not identify any texture or geometry mistakes present in the building models. The overall visual quality identified by the participants from the three focus groups was above average, suggesting that the 3D modelling approach is an effective means for modelling buildings with high visitation and significance. DOI: 10.3138/carto.49.4.2522
Perceptually Shaded Slope Maps for the Visualization of Digital Surface Models
Thomas Pingel, Keith Clarke
Although shaded relief, or hillshaded, images are a widely used method to represent high-resolution (~1-m) digital surfaces derived from airborne laser (or LiDAR) scans, such displays may become difficult to interpret when they include surface features like buildings, roadways, and natural vegetation. One possible alternative as a visualization of such surface models is a representation based on slope shading – the steeper, the darker – but attenuated to the perceptual bias of overestimation of slope. The empirical work presented here demonstrates that Perceptually Shaded Slope Maps (PSSMs) perform as well or better than either hillshaded or hypsometric images on map-reading tasks, including profile estimation and mental rotation. DOI: 10.3138/carto.49.4.2141
A New Database Visualization Framework for the Automatic Construction of Non-standard Charts: Re-creating the Chart of Napoleon's Russian Campaign of 1812
Wei Shi, Randy Goebel, Tanaka Yuzuru
In the last decade, research on database visualization has made great progress in automatically constructing charts composed of standard primitive charts. The next research challenge is to automatically construct non-standard charts which cannot be simply composed with standard primitive types of charts. One typical example is the chart of Napoleon's Russian campaign of 1812. As to the challenge of automatic construction of such complex charts, we may classify conventional visualization frameworks into two categories. The first category asks users to procedurally define non-standard charts by programming. The second category asks users to declaratively define non-standard charts with their logical specification using a given library of graphical objects. Here we will propose a new visualization framework in the second category for automatically constructing non-standard charts from their logical specifications and discuss how to apply our framework to create custom-made geovisualization charts. Such a specification is described by one or more pairs of data view schemata (DVSs) and chart view schemata (CVSs). Each DVS is used for manipulating the data store in a database. Each CVS is used for defining the rendered appearances of the different chart components. Using our framework, users can easily re-create and extend such complex non-standard charts as the chart of Napoleon's campaign by simply providing their logical specifications. DOI: 10.3138/carto.49.4.2487
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Posted by T Hawkins, UTP Journals