In many highly dense urban environments, the urgent needs of residents for increasing green space, improving the quality of the community environment and reconstructing the relationships among residents have given birth to the new space type of community gardens. However, China still lacks this relevant experience. In contrast, New York City’s community gardens had a relatively early start, and they now have rich experience in space construction, operation and maintenance. Given their level of experience, they can be used as references for the development of community gardens in China. This paper adopts a bibliometric research method, identifies 201 periodical literature sources published between 2000 and 2020 from the core library of the Web of Science as the object of study, and finally assesses the research hotspot for transferring from macro-research to space-type construction method, social impact, and so on, through CiteSpace software analysis. By virtue of the research process analysis and the results of field surveys and interviews, this paper probes the development status of space construction and social organization construction of the community gardens in New York City, and summarizes that area’s effective experience of development. Based on the current development situation of China’s community gardens, it is proposed that the development of community gardens should be directed by ensuring the land for development, giving full play to social benefits, and mobilizing social organizations, so as to effectively realize urban space construction and social governance.

To cope with the difficulties of integrating migrant workers into urban life and inefficient land use caused by conventional urbanization, China has proposed a new type of urbanization policy. This policy may have a significant impact on the spatial patterns of rural settlements in China. Exploring this potential impact is conducive to the proposal of scientific plans for the spatial patterns of rural settlements. Therefore, this paper chooses Dingzhou, one of the pilot cities of this new-type urbanization, as the research area to carry out a simulation study on the impact of the new-type urbanization policy. Dingzhou has invested heavily in the new-type urbanization construction in recent years, but the influence of the policy on rural settlements remains unclear. Based on the theoretical framework of previous studies, this paper set up three scenarios, namely “conventional urbanization”, “new-type urbanization”, and “counter-urbanization”. This paper used FLUS (Future Land Use Simulation) Model and various spatial data to simulate the spatial patterns of rural settlements in Dingzhou in 2030 under the different scenarios. By comparing the different scenarios, the impacts of the new-type urbanization policy on the spatial patterns of rural settlements in Dingzhou were evaluated. The results indicated that: (1) From 2000 to 2015, the area of rural settlements in Dingzhou increased by 11.12%. Spatially, the density of rural settlements around the cities and towns increased, and rural settlement areas were mainly converted from cultivated land. Rural settlements were mainly transformed into urban land and cultivated land. (2) The overall simulation accuracy of FLUS was 0.89, so it can be well applied to the simulation of rural settlements. (3) In all three scenarios, rural settlements expanded along their edges, and the closer they were to towns, the more obvious the expansion was. In the counter-urbanization scenario, the change of rural settlements was most dramatic. (4) The new-type urbanization policy makes the spatial patterns of rural settlements in Dingzhou more stable and more intensive.

Beijing Municipal Administrative Center (Beijing MC) in Tongzhou District has inherited the non-capital core functions of Beijing’s central urban area, and its rapid construction and development urgently require a scientific understanding of the pattern of land use evolution in the region. This paper analyzes the pattern of land use evolution in Tongzhou District over the past 40 years, from 1980 to 2020. According to the historical evolutionary characteristics of land use and urban development planning goals, combined with the driving factors of cultural tourism development, the Future Land-use Simulation (FLUS) model is used to simulate the spatial distribution of land use in Beijing MC (Tongzhou District) in 2035 under three scenarios of urbanization acceleration, deceleration and sustainable development. The results show three major trends. (1) Beijing MC (Tongzhou District) is dominated by urban development and construction. During the high-speed urbanization stage from 1980 to 2010, the urban expansion pattern of “along the Sixth Ring Road and along the Grand Canal” was formed. During the low-speed urbanization stage from 2010 to 2020, the land distribution was stable, and Tongzhou District formed a pattern of urban-rural differentiation and land intensification from northwest to southeast. As a typical area of ??Tongzhou District’s urbanization, Beijing MC has the same characteristics of the temporal and spatial evolution as Tongzhou as a whole. (2) By 2035, there are significant differences in land use among the three scenarios with respect to the magnitude of change and spatial distribution. The area and distribution of ecological land under the urban sustainable development scenario are optimal, which is conducive to the realization of sustainable urban development. In analyzing the degree of conformity with the three Beijing MC zoning plans, the prediction simulation under the sustainable development scenario is highly consistent with the land use of the “Beijing Municipal Administrative Center Regulatory Detailed Planning (Block Level) (2016-2035)” (hereinafter referred to as “Planning”) issued by the municipal government. However, there are certain deviations between the simulation predictions in the cultural tourism function area and the livable living scenery area and the corresponding “Planning” expectations. During the urban construction process, the internal ecological land area still needs to be increased. (3) Tongzhou District may lack a close connection between the urban and rural areas in the southeast. Potential risks such as the imbalance in the development of northern and southern townships require further attention in the development process. The prediction and simulation results of the model can provide certain data and methodological support for the construction of a harmonious and livable city in Beijing MC (Tongzhou District).

The Landsat images of the 2000, 2005, 2010, 2015, 2018 are selected as the data source to retrieve land cover and surface temperature data. The contribution of Sink-Source landscape pattern to the heat island and its ecological effects on urban and rural gradient were analyzed by using Heat Index (HI), Sink and Source Landscape Contribution (CI_sink, CI_source) and Landscape Effect Index (LI) in Haikou. The results show that the heat island is concentrated on the West Coast, and in the central urban and Jiangdong New Area; the HI shows a pattern of decreasing value with the following land types: “Bare land>Artificial surface﹥Source landscape>Shrub grassland>Farmland>Sink landscape>Woodland>Water body”. In the central city section, the CI_sink and CI_source are relatively large in these five periods. The LI decreases rapidly along the urban-rural gradient, promoting the Urban Heat Island (UHI) to a large degree. In contrast, the suburban area contributes to a lesser degree. Overall, the LI fluctuates, the proportion of mitigating UHI is large, and there is a second peak outside the city center. The existing Source-Sink Landscape contributes the most to UHI in the central urban area, and this contribution decreases along the urban-rural gradient. With the continuous expansion of city-town areas, the proportion of Sink areas has increased along the gradient, and the proportion of Source areas has subsequently declined, resulting in the spatial transfer and diffusion of UHI. Therefore, a UHI mitigation strategy based on the theory of regional landscape systems is proposed here.

With the expansion of a city, the urban green space is occupied and the urban heat island effect is serious. Greening the roof surfaces of urban buildings is an effective way to increase the area of urban green space and improve the urban ecological environment. To provide effective data support for urban green space planning, this paper used high-resolution images to (1) obtain accurate building spots on the map of the study area through deep learning assisted manual correction; and (2) establish an evaluation index system of roof greening including the characteristics of the roof itself, the natural environment and the human society environment. The weight values of attributes not related to the roof itself were calculated by Analytic Hierarchy Process (AHP). The suitable green roof locations were evaluated by spatial join, weighted superposition and other spatial analysis methods. Taking the areas within the Chengdu city’s third ring road as the study area, the results show that an accurate building pattern obtained by deep learning greatly improves the efficiency of the experiment. The roof surfaces unsuitable for greening can be effectively classified by the method of feature extraction, with an accuracy of 86.58%. The roofs suitable for greening account for 48.08%, among which, the high-suitability roofs, medium-suitability roofs and low-suitability roofs represent 45.32%, 38.95% and 15.73%. The high-suitability green buildings are mainly distributed in the first ring district and the western area outside the first ring district in Chengdu. This paper is useful for solving the current problem of the more saturated high-density urban area and allowing the expansion of the urban ecological environment.

Harmonious urban color can reduce urban light pollution, relieve the urban heat island effect, improve the living quality and form a distinctive style. However, due to the manifold architectural styles, urban color in metropolises typically becomes complicated, which may destroy the color harmony of metropolises. Up to now, there has not been enough research on the quantitative expression of the degree of color harmony, and the research on comparing the urban color characteristics of different metropolises is also relatively insufficient. This paper firstly developed a method to quantitatively measure the degrees of color harmony (DCHs) of five metropolises in 2020: London, Tokyo, Chicago, Paris, and Beijing, by writing a Python program and using the Sentinel-2A remote sensing data. GIS buffers were then used to analyze the spatial distribution of the DCHs within each metropolis. In addition, 20 typical samples were selected to analyze the differences of the DCHs between residential and industrial areas. The results showed that: (1) The values of the DCHs of London and Tokyo were the highest, followed by Chicago and Paris, while Beijing was the lowest. (2) The values of the DCHs were increasing from the inside out in Chicago, Paris, and London, while those in Beijing and Tokyo were decreasing. (3) The values of the DCHs in industrial areas were much lower than in residential areas. Based on the above results, policy implications are provided for color management of these metropolises. Lastly, this study may provide a method for the rapid analysis the DCHs for other metropolises.