4.2. Interpreting the Spatial Syntax Analysis of Nanyang
Because the aim of this research is to explore the relationship between the space syntax analysis model of a historic and cultural block and tourists’ perception, the road network of Nanyang is segmented according to the principle of the minimum space syntax model, and the total number of axes is 315. The current road network and water channels are illustrated in
Figure 1, which is the town planning for 2030. In this map, it is clear to see that the Grand Canal goes across the town and breaks many roads, and multiple squares are located at the ends of the roads.
Then, a magnified aerial map of the main tourist street near the Grand Canal is shown in
Figure 2. Tourist attractions such as residences, palace, temples, etc., are marked and highlighted. In view of the difference between the ancient town area and non-ancient area, the research focuses on the ancient town area and the total number of axes in the ancient town area is 40.
In the results of space syntax-based analysis, the colours refer to high and low values; red refers to high values, while blue refers to low values of integration. On the whole, the axis structure of the ancient town area in Nanyang is not relatively simple. The Nanyang street as a clear ‘vertical’ main tourist street, connects the main tourist attractions such as the Bring-baby Palace and the River-god Temple. Because of the mixed functions of tourism and residence within the block, many living lanes are enclosed to form an independent closed space, or exist in the form of a ‘broken road’, that results in the weak spatial connectivity of the whole block. The results of space syntax analysis variables for 10 streets and seven hutongs are shown in
Table 3, where the average connectivity value for the 17 lanes is only 5. That is, there are on average five axis intersections with each street axis.
The space syntax model analysis result based on four values are presented in
Figure 3 where the red and blue denote the high values and low values, respectively. As the colour contour shown in
Figure 3a, there is a significant difference in the connectivity of the axis of different functional streets, and the average control value is 2.01 in the ancient town area. Since the historic and cultural block of Nanyang is a pedestrian street, the local integration value and mean depth value at walking scale were selected to analyze the compactness and accessibility of the ancient town area. On the whole, the space compactness of the historic and cultural block of the ancient town area in Nanyang is not strong. The local integration value of the main tourist streets is 85.236 (see
Table 3).
Figure 3b depicts the local integration value of streets in the ancient town area and it is obvious that Nanyang Street has the highest value, which is 124.960. This value is ~50% higher than the average value in
Table 3. On the contrary, the mean depth value is illustrated in
Figure 3c where Kaiyang Street has the lowest value, 2.961, which is ~50% compared to the average value. Considering the results in
Figure 3b,c, it is worth noting that Nanyang Street with the highest degree of local integration is the main tourist street intersecting in the middle of the block, and also the streets with the lower mean depth value. However, the level of accessibility of the lanes near the Grand Canal is relatively low, such as Kaian Street on the east of the Canal. This shows that at the walking scale, the block has an obvious central structure. The main tourist street in the middle of the block has the strongest accessibility, convenience, and public exposure and is the main passageway of the block space organization. This obvious central structure strengthens the convergence of people and provides historic sites or attractions in the central region with a clear geographical advantage. Therefore, the central structure of the ancient town area is obvious, and the main tourist street has the potential to offer a strong public interface. The global integration value, see
Figure 3d, could test the compactness of all nodes in the whole system.
As the colour contours in
Figure 3d and values in
Table 3, there are three streets with the highest global integration values, namely, Jinger Street (145.869), Shuangyang Street (130.595), Zhuangyuan Street (129.714). Li and Duan [
30] suggested that a stronger global integration value makes it easier to accumulate pedestrian flow. Therefore, Jinger Street, Shuangyang Street, and Zhuangyuan Street are the most public and convenient spaces for tourists to gather.
Spatial intelligibility is used to measure the cognitive degree of a spatial group. If a spatial group has a high degree of intelligibility, this means that its overall spatial layout is more easily recognized and mastered by people [
31]. People’s cognition of the whole always comes from local information, and the degree of intelligibility reflects the difficulty of judging the whole information according to the local information of spatial groups. The characteristic of comprehensibility means that what one can see from the spatial layout matches or is a useful guide for what one cannot see [
9]. For systems lacking intelligibility, there are many connected spaces, that often cannot be well integrated into the whole system. Therefore, according to the visible connections, one can often be misled into understanding the orientation of this space in the whole system [
10]. In the space syntax model, intelligence value can measure whether the local space and the whole space are related and unified [
9]. Generally, the range of the intelligence value R
2 is 0–0.5, which indicates that the spatial identifiability is weak; R
2 locates at 0.5–0.7 which indicates that the spatial identifiability is good; R
2 locates at 0.7–1.0 which indicates that the space recognizability is strong [
32].
In consideration of the high density of historical buildings in ancient canal towns, this research is conducted using the method of segmentation axis and isovist maps based on space syntax [
15]. The Depthmap is used to extract the connectivity value of the historical and cultural block of the Nanyang ancient town area, according to the following formula:
This is introduced to calculate the intelligibility value R
2 of the historical and cultural block of the Nanyang ancient town area, where
refers to the integration value,
refers to the average of the
of all units, and
is the average value of the
of all units in space. The intelligibility value is calculated as 0.641 as shown in
Figure 4. The value indicates that the recognizability of the street axis of the block is good. The intelligence value in Nanyang ancient town reflects that it is not difficult to establish an impression from the local part to the whole ancient town when tourists were walking in the main streets.
However, when considering that the functions of tourism, commerce, and residence are haphazardly mixed within the ancient town area, rather than being clearly defined in different sub-precincts, tourists often find themselves walking into semi-private residential areas, which is at first seem part of the public domain. In addition, with the renovation of shops and residential areas in recent years, part of the Hutong and lanes within the block has been interrupted, such as Beiqi Hutong and Beier Hutong. This makes it more difficult for tourists to obtain the overall spatial information of the block efficiently. Therefore, the spatial identifiability of Nanyang ancient town area should be strengthened by upgrading the laneway infrastructure, providing cognitive thresholds between public, semi-public and private areas, and developing a flexible wayfinding strategy for tourists as the town undergoes continued renovation.
In this case study, visibility graph analysis (VGA) is conducted on a block beside Zhuangyuan Bridge. The location of the block for the case study in the ancient town as well as the buildings within the block, as shown in
Figure 5. VGA is primarily applied to a building or a semi-urban scale in order to derive how visibility defines relationships of spatial elements and helps to understand the surrounding space [
33].
The VGA results of the selected block based on four view locations were reported in
Figure 6 where the white eye symbol denotes the view of one tourist. The red space is the space that the pedestrians need to take more turns on the route through the block to see, and hence takes longer to be revealed and become available for tourists [
34]. Based on Kaplan’s research [
35], the red space has greater depth and enhanced mystery. As the analysis results show in
Figure 6, the largest red colour regions were found when the tourist stands at the right east of the block. The yellow, the green and the blue space denote the second least noticed space, the second most noticed space, and the most noticed space, respectively. A little more space is visible for tourist standing at the south. Then, from the north and west perspectives, much more space is available for tourists in terms of visibility.
Besides the VGA, the pedestrian flow simulation is conducted and the results based on the four main entrances are shown in
Figure 7, where the white triangle symbol denotes the main entrance locations and the directions for pedestrian flow. High pedestrian flow is found in the regions near the entrance as well as the center region of this block. The integrated prediction is shown in
Figure 8 and it is clear that, regardless of the perspective, the space in the middle of the block (Songzi Hutong) has the highest pedestrian flow. This may be an important consideration for designers, investors, and policymakers when restoring and enhancing the area for tourists.
4.3. Comparing the Results of Nanyang with Wuzhen
Wuzhen is regarded as the comparative case study in this paper. As with Nanyang, the Grand Canal crosses the town of Wuzhen and has also formed a special cultural relationship based upon water. However, unlike Nanyang, Wuzhen has become a very popular tourist destination along the Grand Canal as the town area map shown in
Figure 9 where the highlighted region is selected for comparative study
The space syntax model analysis results based on four values on Wuzhen were illustrated in
Figure 10. The space syntax analysis variables of Wuzhen are summarised in
Table 4 where the results for the east area and west area are separately listed. As shown in
Figure 10a, the highest global integration values were observed in Shifuonan Street and Ziye Road which are located at the boundaries of Wuzhen town. The connectivity values of the streets in Wuzhen are quite different as shown in
Figure 10b, however, the high average value in
Table 4 indicates a much higher connectivity in Wuzhen than Nanyang. Then, both the highest local integration value and mean depth value were observed in streets in East Scenic Area as shown in
Figure 10c,d, respectively. Therefore, this comparative study investigates the spatial structure of Wuzhen to see if there are any significant differences in the space syntax variables between the two towns (see the comparison between
Table 3 and
Table 4) and, therefore, provides a more informed understanding of the spatial structure, especially relating to route complexity, which may contribute to a favourable canal town experience.
The similarities and differences of the Nanyang ancient town area and Wuzhen ancient town area are evaluated and summarised in
Table 5. On the whole, compared with Wuzhen, the axis structure of the ancient town area in Nanyang is relatively simple. Because of the mixed functions of tour and residence within the block, many living lanes are enclosed to form an independent closed space, or exist in the form of a ‘broken road’, which results in the weak spatial connectivity of the whole block. Therefore, the average connectivity value is only 5 in Nanyang, that is, there are on average five axis intersections with each street axis. However, the average connectivity value in
Wuzhen is 9. Additionally, two streets connecting Nanyang Dam have the highest value in Nanyang, and two entrances in West Scenic Area have a relatively high value in Wuzhen. In Nanyang, the highest value is the main tourist street. In Wuzhen, a vehicle-way running through the East and West Scenic areas has the highest value. The intelligibility value of Nanyang ancient town area, which is 0.641 and indicates that the recognizability of the street axis of the block is good.
The intelligence value in Nanyang ancient town reflects that it is easy to establish an impression from the local part to the whole ancient town when tourists are walking in the main streets. On the other hand, in Wuzhen’s ancient town area, the intelligence value is 0.356 as the results show in
Figure 11. This means that it is not easy to form an overview or cognitive impression for the people who are first-time visitors to the town, which would appear to increase the level of intrigue and enhanced mystery about the town.
4.4. Suggestions for Nanyang and Future Research
Sustainable heritage tourism aims to maximize the quality of tourists’ experience and minimize their impacts to protect resources for the next generations, and this is what visitor management intends to achieve [
36]. Jones [
37] explored sustainable heritage tourism, and demonstrated the need for landscape harmonisation to occur. His research reviewed the historical evolution of sustainable heritage landscape. In addition, Jones and Beza [
38] proposed that good sustainability citizenship should depend on heritage tourism’s values and cultural perspectives. Therefore, space syntax should be considered as a tool to help improve the quality of tourists’ experience of sustainability in heritage tourism.
In this research, Beiyi Hutong in Nanyang has the lowest connectivity value and control value in the ancient town area, Kaiyang Street has the lowest mean depth value, and Matou Street has the lowest local integration value.
Based on the space syntax analysis results, and combined present situation of the streets, several suggestions for improving tourists’ spatial cognition in historic districts in Nanyang are proposed in
Table 6. Through a consideration of the road network integration of tourist sites and historic districts, the findings suggest a conservative restoration to solve current negative tourist perceptions of Nanyang. For example, if the Beiyi Hutong is rebuilt to raise its connectivity, the visiting time will be extended and the boring feeling of the tourist mentioned above might be diminished; two potential gathering centers in would also improve integration values of the town so as to prevent the overcrowded situations.
While Nanyang’s overall block structure is clearly more regular than that of Wuzhen, it does not offer the opportunities to reduce intelligibility value, and hence the sense of perceived mystery that Wuzhen evokes on the first impression. The opportunities of applying VGA at a micro-scale or sub-block level, may allow designers to help establish a more intimate sequence of spaces at Nanyang between the Hutong and the Grand Canal, and the western sub-blocks between the Hutong and the lake.