Spatial distribution of measured parameters, such as the Si II 6355 EW, light-curve shape parameters Δm₁₅(B), and photospheric expansion velocities Si IIλ6355, for different subtypes of Type Ia supernovae. Data were collected from multiple sources (Blondin et al. 2012; Silverman & Filippenko 2012; Wang et al. 2009a; Zhang et al. 2014; Zhai et al. 2016). The position of SN 2021wuf is marked with a black triangle. The left panel displays the spatial distribution of Si IIλ6355 EW and the Δm₁₅(B) for the subclasses defined by Branch et al. (2009), while the right panel shows the spatial distribution of Si IIλ6355 EW and photospheric expansion velocities measured from the absorption minimum of Si IIλ6355 lines at B-band maximum for the subclasses given by Wang et al. (2009a) and Zhang et al. (2014).