  Although many tools have been presented in the research literature of
software visualization, there is little evidence of their adoption. To choose a
suitable visualization tool, practitioners need to analyze various
characteristics of tools such as their supported software concerns and level of
maturity. Indeed, some tools can be prototypes for which the lifespan is
expected to be short, whereas others can be fairly mature products that are
maintained for a longer time. Although such characteristics are often described
in papers, we conjecture that practitioners willing to adopt software
visualizations require additional support to discover suitable visualization
tools. In this paper, we elaborate on our efforts to provide such support. To
this end, we systematically analyzed research papers in the literature of
software visualization and curated a catalog of 70 available tools that employ
various visualization techniques to support the analysis of multiple software
concerns. We further encapsulate these characteristics in an ontology. VISON,
our software visualization ontology, captures these semantics as concepts and
relationships. We report on early results of usage scenarios that demonstrate
how the ontology can support (i) developers to find suitable tools for
particular development concerns, and (ii) researchers who propose new software
visualization tools to identify a baseline tool for a controlled experiment.
