Land use multifunctionality (LUMF) is a pragmatic means of resolving land use conflicts and realising regional sustainability and has critical importance in land system science. In this study, we constructed LUMF classifications from a sustainable perspective and quantified and analysed the deliveries of land use functions (LUFs) in the coastal area of Jiangsu Province, China. On this basis, the “bundle” concept was innovatively introduced into the LUMF research framework to analyse the spatiotemporal effects of trade-offs and synergies among multiple LUFs. The results showed that high-value LUF geographic units tended to cluster in human-dominated landscapes. During the study period (2000–2018), the average provision of regional multifunction increased slightly, while the subfunctions changed in different trends. Four LUF bundles (agricultural zone, mosaic cropland–rural housing zone, coastal natural and seminatural landscape zone, urban development zone) were identified, each having different dominant LUFs and landscape configurations. In each LUF bundle, the most common trade-offs were observed in the environmental and economic functions. The space incompatibilities caused by land development demand in different subregions created a trade-off and synergy among multiple functions. Moreover, LUF relations were not static over time, owing to the effects of urbanisation, coastal reclamation activities, and agriculture protection policies. Based on the above results, this research proposes land use optimisations for different multifunctional areas.

Agricultural reclamation in coastal zones is effective for mitigating population pressure on the food supply. Soil properties are important factors influencing crop production in reclaimed coastal lands. This study aims to investigate the impacts of time and land use trajectories on soil physicochemical properties after reclamation. We sampled soils in areas that were reclaimed in 1999, 1998, 1991, 1989, 1986, 1981, and 1979 and determined some soil physicochemical properties such as electrical conductivity with a 1:5 soil:water ratio (EC1:5), exchange sodium percentage (ESP), sodium adsorption ratio (SAR), pH, organic matter (OM), total nitrogen (TN), alkaline hydrolyzable nitrogen (AN), cation exchange capacity (CEC), total phosphorus (TP), available phosphorus (TP) and soil particle size ratio. We analyzed their correlation with land use and the time since reclamation using one-way analysis of variance (ANOVA) and principal component analysis (PCA). The results showed that soil physicochemical properties changed significantly after agricultural reclamation. Soil EC1:5, ESP, and SAR declined rapidly, and OM, TN, and AN increased rapidly during the 29 years after reclamation. The soil particle size ratio was not significantly correlated with reclamation time. The land-use trajectories identified after reclamation had obvious effects on soil physicochemical properties. Aquaculture ponds were superior to cultivated land in terms of decreasing soil salinity but were inferior in terms of soil nutrient accumulation. In the future, more attention should be given to the environmental effects of agricultural reclaimed soils.

Urban fringe is an active expanding belt, indicating urban-rural interaction processes. Previous studies have attempted to define urban fringe as the transitional area between urban and rural areas, but there is a lack of quantitative analysis of the periphery boundaries. We developed a novel, the Spatial Segmentation Model (SSM), to detect the extent of urban fringe via calculating the share of the built-up land. Within the urban fringe, we statistically compared the number of built-up patches in each direction and described four urban expanding patterns (stable, sprawling, leaping, and mixing patterns) indicated by the empirical analysis. The results show that this model can reliably detect the urban fringe and could reveal urban growth characteristics. We find the spatial territory changes are highly relative with transport infrastructures in Harbin. Meanwhile, the roads density in the urban core are higher than in the urban fringe. Especially for city roads, roads density in the urban core is more than 4 times higher than in the urban fringe. The growth of the urban fringe is closely related to the development of social economies as well as the space policies and development plans designed by governments. Similar to the post-industry cities worldwide, Harbin should take action to address population decline. Effective land-use and suitable urban growth strategies play an important role in alleviating urban shrinkage. Thus, understanding the dynamics, urban expanding patterns, and driving factors in the urban fringe can help us form a basis for future urban development.

Data from the optical satellite imaging sensors running 24/7, is collecting in embarrassing abundance nowadays. Besides more suitable for large-scale mapping, multi-view high-resolution satellite images (HRSI) are cheaper when comparing to Light Detection And Ranging (LiDAR) data and aerial remotely sensed images, which are more accessible sources for digital surface modelling and updating. Digital Surface Model (DSM) generation is one of the most critical steps for mapping, 3D modelling, and semantic interpretation. Computing DSM from this dataset is relatively new, and several solutions exist in the market, both commercial and open-source solutions, the performances of these solutions have not yet been comprehensively analyzed. Although some works and challenges have focused on the DSM generation pipeline and the geometric accuracy of the generated DSM, the evaluations, however, do not consider the latest solutions as the fast development in this domain. In this work, we discussed the pipeline of the considered both commercial and opensource solutions, assessed the accuracy of the multi-view satellite image-based DSMs generation methods with LiDAR-derived DSM as the ground truth. Three solutions, including Satellite Stereo Pipeline (S2P), PCI Geomatica, and Agisoft Metashape, are evaluated on a WorldView-3 multi-view satellite dataset both quantitatively and qualitatively with the LiDAR ground truth. Our comparison and findings are presented in the experimental section.

The spatial equality of urban public services and their accessibility are a crucial aspect of urban sustainability. However, there is currently a lack of a composite proxy that can effectively assess public service equality with fine granularity. To address this gap, we have developed a new indicator based on the concept of location dominance. This indicator accumulates access opportunities to public services with a time-weighted decay function at granular level. Our findings reveal that location dominance in Shijiazhuang follows a pronounced core–periphery pattern. Efficient travel modes can significantly enhance location dominance and increase spatial equality, aligning with people’s travel preferences. Additionally, we discovered an extremely strong linear correlation between three key urban development elements (i.e., nighttime lighting data, land use intensity, and population retention rate) and location dominance. The discussion of these findings confirms the validity of our method and the reliability of our results. Consequently, this method and its outputs can aid policymakers and urban planners in swiftly identifying subtle disparities in spatial accessibility for public services, thereby promoting urban equality and sustainability.