## 4 Results and Analyses
### Spatial Structure of Linkages and Node Identification  
Beyond aggregate flows, our analysis examined the spatial distribution of intercity connectivity within Jurong. By mapping the OD flows at the 1 km grid level, we identified specific locations in Jurong that serve as key conduits for travel to and from Nanjing or Zhenjiang. The results reveal a highly uneven internal connectivity geography in Jurong. Figure 9 illustrates the density of intercity travel origins and destinations across the Nanjing-Jurong-Zhenjiang area. The flows between the three cities tend to concentrate in a few hotspots rather than being uniformly spread. As expected, the highest density of trips linking to Jurong (and Zhenjiang) originates from the main urban core of Nanjing (notably, downtown districts such as Gulou and Xuanwu). This reflects that many of the people traveling to Jurong from Nanjing are based in the city center or major hubs of Nanjing (where jobs and universities are concentrated). In Zhenjiang, there is a modest concentration of trips in the city center connecting to Jurong, but, interestingly, this does not stand out as a high-intensity cluster on the map. In other words, the volume of travel between the core of Zhenjiang and Jurong, while present, is not sufficient for creating a \"bright\" hotspot that is comparable to those observed in Nanjing or Jurong. This again underscores the secondary nature of the interaction between Zhenjiang and Jurong. Within Jurong itself, two primary intercity connectivity clusters emerge: Jurong city center and Baohua Town (in the northwestern part of Jurong) (Figure 9). These two areas exhibit the highest density of incoming and outgoing intercity trips. The city center of Jurong, which is the administrative and commercial heart of the city, naturally functions as a collection and distribution point for travel--it is where major roads intersect and where many people live or work; thus, many trips either start or end here. Baohua Town,  
Figure 9: Space diagram of the number of OD connections. on the other hand, is a township on the western edge of Jurong, directly bordering the Nanjing metropolitan boundary (near the Qixia District of Nanjing, which includes the Xianlin University Town area). The data reveal that Baohua has developed into a significant gateway for Nanjing-Jurong interactions. In fact, the Baohua area and the adjacent Nanjing Xianlin sub-district together form a continuous high-mobility zone, indicating a seamless spillover of urban influence from Nanjing into the territory of Jurong at that location. This is likely due to the proximity of Baohua to the suburbs of Nanjing and the presence of convenient highways (and possibly a commuter rail station) linking Baohua with the downtown area of Nanjing within a short travel time. As a result, Baohua has attracted residential developments and commuters who effectively live in Jurong but work or study in Nanjing. To systematically assess and categorize the subregions of Jurong based on their connectivity patterns, we analyzed each of its 12 units, comprising four streets and eight towns, using two key metrics: the total volume of intercity trips (combined flows to Nanjing and Zhenjiang) and the directional balance of these connections (whether flows are predominantly oriented toward Nanjing, Zhenjiang, or both). The findings reveal distinct spatial patterns, which can be summarized as follows (Table 2, Figure 10):  
* High-potential node areas: The central city of Jurong (urban core) and Baohua Town clearly fall into this category. They each have the highest total intercity flow volumes, and they also each maintain multiple strong linkages. The city center of Jurong, for instance, sends and receives large flows from multiple directions--it connects robustly with the main city districts of Nanjing and the central district of Zhenjiang and even has notable interactions with other nearby cities such as Danyang (an adjoining city under the jurisdiction of Zhenjiang).