Consistent Layout for Thematic Software Maps

TL;DR

This paper introduces a method for creating consistent, vocabulary-based software maps using LSI and MDS, enabling meaningful comparison of software artifacts and their evolution over time.

Contribution

It presents a novel layout approach that reflects software vocabulary and similarity, improving the comparability of different software visualizations.

Findings

The layout reflects software vocabulary and similarity effectively.

It enables comparison of different software maps.

The approach is stable over software evolution.

Abstract

Software visualizations can provide a concise overview of a complex software system. Unfortunately, since software has no physical shape, there is no "natural" mapping of software to a two-dimensional space. As a consequence most visualizations tend to use a layout in which position and distance have no meaning, and consequently layout typical diverges from one visualization to another. We propose a consistent layout for software maps in which the position of a software artifact reflects its \emph{vocabulary}, and distance corresponds to similarity of vocabulary. We use Latent Semantic Indexing (LSI) to map software artifacts to a vector space, and then use Multidimensional Scaling (MDS) to map this vector space down to two dimensions. The resulting consistent layout allows us to develop a variety of thematic software maps that express very different aspects of software while making it easy to compare them. The approach is especially suitable for comparing views of evolving software, since the vocabulary of software artifacts tends to be stable over time.