In this work, we first outline the expectations for benzene (a π system) with different substitution patterns to illustrate how QI maps visualize QI. We then apply this method to butane whose transport properties are calculated using the ladder C model to analyze QI in σ-systems. Finally, we compare the QI between the πsystem and σ-system. We see that the orbital contributions to QI in π-systems and σ-systems are quite different, with the QI in π-systems caused by phase alteration and in σ-systems caused by the change in the width and position of the individual MO transmission peaks.