Geotechnical lasso (Glasso), which is a data-drive site characterization (DDSC) method proposed by the authors, is advantageous to identification of abrupt changes in data such as soil layer boundaries because it is formulated with piecewise functions. In Glasso, target grounds are split into many cells or cuboids, and geotechnical parameters for all the cells/cuboids need to be identified. It requires massive computation time and memory space and has limitations for high degree-of-freedom (DoF) problems. This study newly proposed a Glasso based on continuous basis functions (BFs) to reduce DoF, i.e., to address the limitations of the existing Glasso. The applicability of the proposed Glasso with BFs is investigated through DDSC for virtual grounds. This study also shed a light on the advantages and disadvantages of two types of Glasso based on the comparison.