In this paper, we discuss whether data collected from monitoring software developers' logs can be considered big. We hypothesize that it falls within the category of Big Data. The main topic of our paper however, is how to facilitate analysis of such data. Due to the specificity of the monitored activity, the analysis is at least partially explorative in its nature. We hypothesize that visualisation can be a productive approach in such a case. We present several visualisation schemes (diagram types) and show those applied to explorative analysis of data gathered within one four year project that we have been participating in.