## 3 Data Acquisition and Research Method
### Empirical Observation and Field Study: The Obsolescence of the Existing Resettlement Communities  
A detailed analysis of the spatial features of six communities was carried out, which represents well the characteristic conditions of this kind of settlement in Suzhou (Figure 2). The communities are:  
* Li He Village, started in 1994 in Gusu District;
* Nanhuan Community, started in 1996 in Gusu District;
* Dengyun Community, started in 2000 in Xiangcheng District;
* Lotus Village, started in 2002 in Suzhou Industrial Park;
* Bibo Community, started in 2001 in Wuzhong District;
* Mabang Community, started in 2002 in Suzhou New District. The direct observation of the resettlement communities highlights how some elements and standards are constantly repeated:  
* Standards in building characteristics: housing type (multi-story with central staircase and 2 apartments on every floor), number of floors (4-6), depth of buildings (8-12 m with verandas);
* Standards in the spatial layout: orientation and alignment (east-west), distances between buildings (the minimum provision is that the sunshine must enter the ground floor for at least 2 h every day according to the regulation), functions (mono-functional: residential with some public facilities for gathering), and dimensions and features of the common open space;
* Standards in construction quality in compliance with local regulations [87]. Figure 2: The typical inner courtyards of the resettlement communities. The direct observation of the spatial characteristics of the case study was combined with some data on urbanization in Suzhou, such as the rapid growth of the wealthy middle-class population, the rapid adjustment of the economic structure, and the constant attraction of new residents over the years. This allows concluding that resettlement communities can be considered a potentially transformable part of a city for four reasons:  
1. Buildings often have problems with poor construction quality and outdated equipment and appliances. When the building is more than 15 years old, which is often the case in Suzhou resettlement communities, sewage, pipelines, heating and cooling systems, waste management, water and electricity, and waterproof and acoustic equipment should be updated. Regarding the quality of building structures, the Unified Standard for Reliability Design of Building Structures (GB50068-2001) in 2001 first proposed the concept of design service life: it defined the design service life of building structures and structural components as 30 years; in recent years, this service life has increased to 50-70 years [88]. 2. Residential units and public spaces have problems connected to the low standards of their construction period. This includes a lack of elevators, insufficient parking spaces, units often too small to accommodate a comfortable kitchen with a dishwasher and two bathrooms with washing machines [89]. Therefore, the local government is taking measures to address these issues. For example, in October 2018, the local government launched the \"Suggestions on Installing Elevators in Existing Multi-story Residential Buildings in Suzhou\" to adapt to economic and social development, improve the functionality of existing housing, and improve living standards [90]. 3. The value range of FAR is relatively low, indicating that these communities have a small population density and belong to low-density communities. This situation is not due to the age of construction, but rather to the project conditions and the number of people that need to be accommodated [91]. 4. The construction method usually adopted a \"copy-paste\" method to provide similar living conditions while reducing costs and accelerating speed. However, in the future, with the development of China's economy and the improvement of people's living standards, these demolished and rebuilt communities may be considered low-level housing environments.