Figure 1.
Each map was featured with four different kinds of grids (upper left: continuous lines, upper right: dashed lines, lower left: crosses, lower right: no grid). The example used in this illustration is the map of Sendenhorst, Germany – derived from ATKIS-Basis-DLM (cf. Figure 2).
Figure 2.
The fifteen maps derived from ATKIS-Basis-DLM.
Each map had a unique combination of DENSITY and LANDSCAPE. The three levels of DENSITY refer to the categories of active object layers. Each level of DENSITY represents a different percentage range of the total number of distinct objects (DOs) −1–10%, 25–45% or 100%. The five levels of LANDSCAPE (highly rural, rural, rural-suburban, urban, highly urban) refer to categories of characteristic topographies as used in cartography. The caption of each map refers to the represented area of Germany's federal state of North Rhine-Westphalia.
Figure 3.
Main effects of the experimental factors (GRID, LANDSCAPE, DENSITY) on hit rate and spatial accuracy.
Hit rate refers to the percentage of correctly recalled places of interest (POIs); spatial accuracy represents the mean distance errors of correctly recalled POIs (in px). The recall of a POI was considered as correct if the recalled location was within a linear distance of 0–28.4 px (0–1 cm) from the location of the original object. Error bars represent the standard error of the mean. * = p<.05; ** = p<0.01; *** = p<.001 (Bonferroni-corrected).
Figure 4.
Interaction of GRID and LANDSCAPE on hit rate.
Hit rate refers to the percentage of correctly recalled places of interest (POIs). Significant linear trends are identified for all four kinds of grids. Continuous (A) and dashed grids (B) also reveal a significant quadratic trend (at p<.05).