“…In addition, multiple data types, such as night-time/day-time satellite images or street views (Abitbol and Karsai, 2020 ; Acharya et al, 2017 ; Gebru et al, 2017 ; Glaeser et al, 2018 ; Mellander et al, 2015 ; Suel et al, 2021 ; Suel et al, 2019 ), district-based spatial information (e.g., the latitude and the longitude) (Suel et al, 2018 ), human mobility records (Smith et al, 2013 ), restaurant information (Block et al, 2004 ), and socio-media records (Hristova et al, 2016 ), were utilised in fine-grained district-based income estimation. Along the line of machine-learning and big data-driven models, Bai et al ( 2020 ) previously developed three fine-grained income estimation models for the developed economies, including the GP-Mixed-Siamese-like-Double-Ridge model, the Mixed-Siamese-like model, and the Spatial-Information-GP model, with inputs from non-field-survey big data only.…”