As mentioned in the Introduction section, one of the major practical applications of visual representation of chemical space in drug discovery is SAR analysis where the concept of chemical space provides a solid and consistent framework for representing the structural data. When activity data are added (e.g., mapped) into a visual representation of chemical space, it is possible to navigate through the chemical space and exploring (qualitatively or quantitatively) variations in activity upon changes in chemical structures. The massive amount of data stored in chemical databases, including incomplete chemogenomic data or activity data obtained at single concentrations, makes visualization SAR difficult; however, is can be aided by the power of visualization tools. Previous studies highlighted advances in methodologies that explore SAR of compound data sets and screening collections .