## 4 Result
### Monitoring Results  
Based on historical monitoring data and current results, this paper delineates the multi-dimensional spatial units of surface subsidence in the urban area of Kunming. The identification and characteristics reveal the heterogeneity of the surface subsidence process and deformation characteristics, which highlights the risk factors in urban planning and land use. The results show (Figure 9) that surface subsidence in Kunming is still ongoing, and overall changes remain relatively stable. However, the subsidence area near the northeastern shore of Dianchi Lake is gradually expanding. In zone B, a new subsidence funnel has appeared in recent years, which is developing rapidly with a trend towards connecting with zone A and zone C in the future (Figure 10). The soft ground, numerous wetlands, and abundant groundwater resources around Dianchi Lake coupled with the rapid urban development and sharp growth in buildings in zone A, zone B, and zone C will inevitably lead to extensive groundwater extraction. Hence, surface subsidence is ultimately exacerbated in these regions. The subsidence phenomena in zone D and zone E occurred earlier, and have remained relatively stable for a period. However, in recent years, the rapid construction of buildings in Chenggong New District has exacerbated the subsidence in zone E.  
These areas have not undergone large-scale urban construction and development, which are related to continuous groundwater extraction. Zone F, as a wetland area without urban buildings, has shown rapid subsidence over the past three years, possibly related to the irrigation of nearby agricultural facilities. The dynamic development of surface subsidence is driven by both environmental conditions and human factors. The accumulation of subsidence and the occurrence of multiple funnels demonstrate that the subsidence process is spatially non-uniform with some areas experiencing rapid subsidence, with localized stress concentration, while others remain relatively stable. Under the background of rapid urbanization, the analysis of zone A, zone B, and zone C highlights that the rapid expansion of urban structures and transportation infrastructure has led to the diversification and complexity of surface subsidence phenomena. All subsidence areas are associated with groundwater depletion. Figure 8: Correlation verification of PS and SBAS ((**A–F**) are the subsidence zones of A–F, respectively). Figure 10: Distribution of sedimentation funnel and road land in subsidence zone B.  
Figure 9: Distribution map of Kunming subsidence funnel ((**A**–**F**) are the subsidence zones of A–F, respectively). By integrating the monitoring results obtained by the PS method and SBAS method (Figures 11 and 12), the Universal Kriging interpolation method is used for analysis. The results show that the subsidence regions monitored and located by the two methods are highly consistent, especially in the subsidence zone A, zone D, and zone E. This shows that both methods can efficiently and sensitively reflect the existing and newly formed surface subsidence areas. This research shows (Figure 13) that in the past three years, the depth of the surface subsidence funnel in the Kunming urban area has continued to increase. The most serious subsidence areas are subsidence zone A and zone C. The cumul  
Figure 11: PS-InSAR monitoring results in the subsidence area of Kunming City ((**A–F**) are the subsidence zones of A–F, respectively). Figure 12: SBAS-InSAR monitoring results in the subsidence area of Kunming City ((**A–F**) are the subsidence zones of A–F, respectively). monitoring points with the most serious subsidence in the past three years has reached 99.4 mm and 83.9 mm, and the average accumulated settlement in the settling area has reached 19.0 mm and 16.4 mm, respectively (Table 3). According to the experimental results (Figure 13), the sedimentation rate also presents a funnel shape in space.