Density visualization of a phenomenon throughout a space is one of the usages of maps. Color coded heatmaps are a popular approach to visualize density. However, heatmaps do not give a quantitative view to the user and it is not possible to estimate quantitative values from their colors. Dot density maps are considered and adapted as an alternative in order to enhance the density visualization to overcome these issues. Two algorithms are developed to make a conventional dot map and a graduated dot map. A conventional dot map contains dots with equal size, while a graduated dot map has various classes of dot sizes on a regular grid. The resulting raster from running the KDE function contains a large number of cells which was used as a base to create dot maps. This base is a grid input in which dots are placed. The dot placement is pseudo random in the conventional dot map whereas it is non-random in the graduated dot map. Both map types avoid any dot overlap and coalescence, as this is a prerequisite to get a quantitative estimation from a dot density map. Two datasets were used to run the algorithms. A user test was carried out to evaluate the degree of enhancement. The test results show that both types of dot maps are significantly superior to the heatmap not only in presenting the overall density, but also in estimating quantitative values in any favorable part of the map. There is no definite superiority between the conventional and graduated dot maps. The test result stated that both of the maps are helpful based on the dataset, homogeneity of a phenomenon, the aim of the map reader, level of details and calculation time.     «

Density visualization of a phenomenon throughout a space is one of the usages of maps. Color coded heatmaps are a popular approach to visualize density. However, heatmaps do not give a quantitative view to the user and it is not possible to estimate quantitative values from their colors. Dot density maps are considered and adapted as an alternative in order to enhance the density visualization to overcome these issues. Two algorithms are developed to make a conventional dot map and a graduated d...     »