A wealth of census data relative to hierarchical administrative subdivisions are now available. It is therefore desirable for
hierarchical data visualization techniques, to offer a spatially consistent representation of such data. This paper focuses
on a widely used technique for hierarchical data, namely treemaps, with a particular emphasis on a specific family of
treemaps, designed to take into account spatial constraints in the layout, called Spatially Dependent Treemap (SDT). The
contributions of this paper are threefold. First, we present the "Weighted Maps", a novel SDT layout algorithm and discuss
the algorithmic differences with the other state-of-the-art SDT algorithms. Second, we present the quantitative results and
analyses of a number of metrics that were used to assess the quality of the resulting layouts. The analyses are illustrated with
figures generated from various datasets. Third, we show that the Weighted Maps algorithm offers a significant advantage
for the layout of large flat cartograms and multilevel hierarchies having a large branching factor.
In this work, we present VAFLE, an interactive network security visualization prototype for the analysis of firewall log events. Keeping it simple yet effective for analysts, we provide multiple coordinated interactive visualizations augmented with clustering capabilities customized to support anomaly detection and cyber situation awareness. We evaluate the usefulness of the prototype in a use case with network traffic datasets from previous VAST Challenges, illustrating its effectiveness at promoting fast and well-informed decisions. We explain how a security analyst may spot suspicious traffic using VAFLE. We further assess its usefulness through a qualitative evaluation involving network security experts, whose feedback is reported and discussed.