We present a study on the visual assessment of relative data point distances in Parallel coordinate systems and scatterplots in Cartesian coordinate systems. Specifically, we assess the impact of coordinate system type, dimension, and relative point distance deviation. We performed an online pilot experiment with 100 participants using Amazon’s MechanicalTurk. The experiment design and methodology are presented in detail and results indicate that there may indeed be a difference in human performance when visually assessing distances in the considered coordinate systems. We argue that further investigations are needed to draw stronger conclusions. These should consider inclusion of other factors into the experiment design, such as the relative angle between data points that is expected to have a significant impact on the outcomes.