Research on the Spatial and Temporal Distribution and Evolution Characteristics of Ancient Architectural Heritage in Southeastern Zhejiang

Abstract

Southeastern Zhejiang boasts a large number of ancient architectural heritage sites and features, representing a rich cultural heritage. However, this region lacks a unified and effective planning system and coordination mechanism. Each county and city operates independently, resulting in low levels of resource sharing and utilization. There is a lack of a long-term, comprehensive, and effective planning and management framework. Therefore, this study focuses on 268 ancient architectural heritage sites in southeastern Zhejiang. By employing correlation analysis methods on the ArcGIS platform, this study summarizes the spatial and temporal distribution characteristics and evolutionary patterns of ancient architectural heritage. The study aims to provide guidance for subsequent comprehensive research, protection, and planning, thereby achieving the sustainable development of the region’s ancient architectural cultural heritage. The conclusions are as follows: (1) Southeastern Zhejiang’s ancient architectural heritage has formed an overall spatial distribution pattern known as the “three cores and three belts”. Targeted sustainable development strategies for ancient architectural heritage can be proposed accordingly. (2) The overall spatial distribution of ancient architectural cultural heritage in southeastern Zhejiang is highly correlated with the natural environment. It is important to consider the correlation between the overall spatial distribution of ancient architectural cultural heritage and the natural environment in the region during subsequent development. (3) The distribution of newly added architectural heritage in southeastern Zhejiang is influenced by factors such as water resource reforms, immigration policies, administrative changes, and cultural ideologies. Throughout history, southeastern Zhejiang has exhibited different spatial distribution structures, laying the foundation for the study of its genealogy and lineage of ancient architectural heritage. The contribution of this research lies in providing targeted references for the coordinated development and systematic revitalization of ancient architectural cultural heritage for the future of southeastern Zhejiang.

1. Introduction

Architectural heritage refers to the remains of human activities from past historical periods that have been preserved to this day. As an important carrier of sustainable development for national culture, it holds significant historic artistic, and scientific values [1]. In the “14th Five-Year Plan” development agenda, strengthening the protection of cultural relics and cultural heritage is regarded as an important aspect of enhancing the country’s cultural soft power. Zhejiang, a place rich with vast cultural heritage, has a long history and rich ancient architectural heritage. In 2020, the Zhejiang provincial government issued the “Development Plan for Zhejiang Poetry Cultural Belt” based on the historical and cultural geographic context of Zhejiang. The plan highlights that the historical sites in southeastern Zhejiang “carry the ancient charm of the past” and that the ancient architectural heritage sites along the route form an important foundation for the development of the poetry cultural belt (Zhejiang Provincial Government, 2020). Therefore, in the current context of national spatial planning, historic architectural cultural heritage, as an important component of the region, holds significant importance for the harmonization of urban and rural living environments, regional tourism planning, and the sustainable development of the architectural heritage itself.

Ancient architectural heritage, which enriches cultural heritage, has always been a hot topic of research both domestically and internationally. Firstly, in terms of research scale, scholars have employed methods such as quantitative geography [2] and GIS spatial analysis [3,4] at the mesoscale level, focusing on administrative units at the provincial and municipal levels, as well as important natural river basins. These methods have been used to analyze the spatiotemporal distribution of architectural heritage in different regions, revealing the internal and external factors, such as policy systems and natural environments [5,6]. At the microscale level, significant achievements have been made regarding the construction techniques, artistic value, disaster protection, development, and utilization of architectural heritage. Secondly, different disciplines have employed various research methods from different perspectives. Architecture, for example, often takes typical ancient buildings as samples and conducts surveys of architectural structures, combined with the study of historic architectural materials, to analyze the material forms [7,8] and construction techniques of wooden components [9,10,11]. Art studies focus on the analysis of detailed components, such as plant motifs [12], geometric patterns [13], and theatrical figures [14,15,16] in ancient architectural heritage, exploring their artistic characteristics. Disaster studies introduce preventive conservation [17,18] and utilize technologies, such as digitization and informatization, to monitor and assess the risk factors for damage to ancient architectural heritage [19,20] and subsequently implement risk prevention measures [21]. Tourism studies employ research methods such as value evaluation [22] and integrate the cultural elements of ancient architectural heritage into tourism products, aiming to achieve the activation of both the economic and cultural benefits of ancient architectural heritage [23,24,25].

In summary, the existing research has formed a relatively mature system. However, in terms of research subjects, these achievements often focus on capturing the static characteristics of typical samples. In the context of current national land planning, there is a relative lack of understanding of the spatiotemporal patterns of ancient architectural heritage sites within a geographical area, especially the insufficient attention given to the spatiotemporal distribution patterns of ancient architectural heritage sites within the same cultural region. Taking the research area of southeast Zhejiang as an example, studies related to its ancient architectural heritage are mostly subordinated to certain chapters of research on ancient architectural heritage in Jiangsu and Zhejiang, with few specialized studies focusing on the southeast Zhejiang region. However, from the perspective of cultural geography, the renowned geographer Wang Shixing (1547–1598) pointed out in his work Guang Zhi Yi that “the Hang, Jia, and Hu plains are the land of water towns, while Jin, Qu, and Yan are hilly and rugged, inhabited by mountain valley dwellers”. As stated in the Li Ji: Wang Zhi, “The materials and customs of residents vary in broad valleys and large rivers”. The ancient architectural heritage in the southeast Zhejiang region is closely related to its folk elements and possesses its own uniqueness, which should not be generalized. Professor Tan Qixiang also emphasizes the need to “pay attention to the geographical distribution and geographical differences of various cultural images” in research.

Based on this, this study focuses on the architectural heritage in southeastern Zhejiang and utilizes the correlation analysis method on the ArcGIS platform to explore the spatiotemporal evolution patterns of its distribution. To some extent, this research can reflect the historical evolution of cultural heritage and the regional social development process in the area [26]. The study aims to further expand the theoretical foundation of the regional natural and cultural heritage system, provide scientific support for the protection and development of cultural heritage in southeastern Zhejiang, and thus establish a sustainable planning and management framework.

2. Overview of the Research Area

The research area of southeastern Zhejiang, as referred to in this study, is a regional delineation based on cultural geography commonly adopted in the research of traditional architecture in Zhejiang [27]. It encompasses Shaoxing, Ningbo, most of Zhoushan, Taizhou, and Wenzhou, as well as Jingning, Yunhe, and Qingtian in Lishui [28]. This region is primarily coastal, with Ningbo, Shaoxing, and Wenzhou located in the plains, while other areas consist of basins and mountains. The region is intersected by water systems such as the Oujiang River and the Cao’e River. Historically, this region has seen the formation of clan villages based on blood ties, and many of them have genealogical records. It is characterized by a rich local culture and a strong atmosphere of agricultural and scholarly traditions. For example, in the genealogical records of clan villages in Nanxi River, Wenzhou, there are often records emphasizing the importance of both agriculture and education, such as “Farming brings wealth, reading brings honor” and “Farming is the foundation, reading illuminates teachings”. The profound historical and cultural heritage has given rise to a diverse range of architectural types, including academies, book pavilions, Confucian temples, and literary pagodas (Figure 1). There are a total of 268 ancient buildings in the study area, including 76 residential buildings, 58 religious buildings, 46 sacrificial buildings, 13 landmark buildings, 52 engineering buildings, 12 landscape architecture, and 12 other types of buildings (Figure 2).

3. Data Sources, Research Methods, and Ideas

3.1. Data Origin and Processing

(1) Considering that the selection and determination of national key cultural heritage sites and provincial-level cultural heritage sites are based on unified criteria, and their historical and cultural value is particularly prominent, this study includes the first to eighth batches of national key cultural heritage sites in Zhejiang province, as announced on the official website of the National Cultural Heritage Administration (http://www.nach.gov.cn, accessed on 10 October 2023) (The first batch of national key cultural heritage sites was announced in March 1961, and the eighth batch was announced in October 2019), as well as the first to seventh batches of provincial-level key cultural heritage sites in Zhejiang province, as announced by the Zhejiang Provincial Cultural Heritage Administration (http://www.zj.gov.cn, accessed on 10 October 2023) (The first batch of Zhejiang Provincial cultural heritage sites was announced in April 1961, and the seventh batch was announced in July 2020).

(2) By reviewing and analyzing the existing research literature, including “Ancient Buildings in Zhejiang” (Yang Xingping et al., 2015 [29]), “Map of Ancient Buildings in Zhejiang” (He Congrong et al., 2015 [30]), Residential Buildings in Zhejiang (Research Institute of Architectural History, China Architecture & Building Press, 2018), “Residential Buildings in Zhejiang” (Ding Junqing et al., 2009 [31]), and local chronicles, representative ancient buildings that reflect regional characteristics were also included as research objects. After excluding data with unknown dates, a total of 268 research samples were finally identified as of July 2020 (The term “ancient architectural heritage” mentioned in this article refers to the category of ancient buildings among the six categories of cultural relics classified by the national and provincial cultural heritage administrations, including ancestral halls, mansions, gardens, temples, pagodas, book collections, ancient water conservancy buildings, coastal defense buildings, ancient opera stages, archways, etc., which basically cover the main aspects of ancient buildings in southeastern Zhejiang).

Currently, the preservation status of ancient architectural heritage in southeastern Zhejiang can be roughly classified into five categories: Category One: Well preserved. The architectural heritage is fully preserved with its original structure, form, and features. Most examples in this category are national key cultural heritage sites, accounting for approximately 33.33% of the samples. Examples include Jia Family Mansion and other buildings. Category Two: Well preserved with potential risks. The architectural heritage retains its original form but faces potential risks such as flooding or landslides. This category accounts for about 16.41% of the samples. Examples include the Taishun Corridor Bridge and others. Category Three: Partially damaged. These buildings have some damage, such as damaged carvings, which may impact cultural identification efforts. However, the overall structure and features are still recognizable, and they possess significant historical and cultural values. This category accounts for approximately 52.00% of the samples. Category Four: Restored. Some architectural heritage sites have undergone restoration work to compensate for the original damages or losses. This preserves the historical and cultural values of such sites. Examples include the Lumen Academy and other buildings. Category Five: Partial change in use. Although the purpose of these buildings has changed, some basic structures and historical features are still preserved. However, the number of buildings in this category is minimal. Examples include the Fuqing Mansion and other buildings.

3.2. Research Methods and Ideas

The study utilizes ArcGIS as the technical platform and abstracts the samples as point features. The spatial data of ancient buildings obtained were associated with attribute data to establish a geographic information database for architectural heritage sites in southeastern Zhejiang. Kernel density analysis provides an intuitive reflection of the specific clustering locations and degree of clustering of architectural heritage sites in southeastern Zhejiang. The nearest neighbor index visually reflects the degree of distribution and diffusion of architectural heritage sites. By employing these two research methods, the analysis and visualization of data related to the evolutionary and distribution characteristics of architectural heritage in southeastern Zhejiang were achieved. This study serves as a reference for subsequent comprehensive research, preservation, and planning of architectural heritage in southeastern Zhejiang. The specific steps are as follows:

(1)

Firstly, the research samples were determined by collecting the geographic spatial information of each ancient architectural heritage site. The spatial attribute data of the research samples were obtained using the Guihuayun website (http://www.guihuayun.com, accessed on 10 October 2023). With ArcGIS 10.8 as the technical platform, a geographic information database of ancient architectural heritage sites in southeastern Zhejiang was established.

(2)

Secondly, the spatial distribution characteristics of ancient architectural heritage sites in southeastern Zhejiang were analyzed. The kernel density analysis method (

Table 1. Kernel density analysis method and nearest neighbor index method.

Formula	Research Method	Model	Parameter Description	Spatial Geographical Meaning
(1)	Kernel density analysis method f(x)	$\mathrm{f}\left(\mathrm{x}\right)=\frac{1}{n{h}^d}\sum _{i=1}^{n}k\left(\frac{x-x_i}{h}\right)$	f (x) represents the kernel density function estimation formula; $\mathrm{k}\left(\frac{\mathrm{x}-{\mathrm{x}}_{\mathrm{i}}}{\mathrm{x}}\right)$ is called the nuclear density equation; H is the bandwidth (h > 0); N is the number of points within the threshold range, and (x − xi) represents the distance at the point event; I is a value from 1 to n.	The kernel density estimation method is used to calculate the density of elements in their surrounding neighborhoods, which has a good effect on analyzing the spatial distribution of point data.
(2)	Nearest neighbor index R	$\mathrm{R}=\frac{{\overline{r}}_1}{{\overline{r}}_E}$$=2\sqrt{D}\times {\overline{\mathrm{r}}}_1$	R is the index of the nearest point, ${\overline{r}}_1$ is the average distance r1 between the nearest points, ${\overline{r}}_E$ is the theoretical nearest distance, and D is the point density.When R = 1, i.e., ${\overline{r}}_1={\overline{r}}_E$, Explanation of uniform distribution of point like elements; When R > 1, i.e., ${\overline{r}}_1>{\overline{r}}_E$, it indicates that point like elements tend to be distributed dispersedly; When R < 1, i.e., ${\overline{r}}_1<{\overline{r}}_E$, it indicates that the point like elements are distributed in a clustered manner.	A geographical indicator that represents the degree of mutual proximity of point-like elements in space. The distribution of point-like elements in space is in three states: uniform, dispersed, and clustered.

) was used to identify the spatial distribution patterns of ancient architectural heritage sites and analyze the topography, landforms, and hydrological features of the region to explore the relationship between the distribution of ancient architectural heritage and the natural environment.

(3)

Finally, the spatiotemporal distribution patterns of ancient architectural heritage sites in southeastern Zhejiang were explored. The quantity of ancient architectural heritage sites in different periods was counted, and their temporal variation characteristics were analyzed. The nearest neighbor index method (Table 1) and kernel density analysis method were utilized to visualize the spatial distribution of ancient architectural heritage in different periods, aiming to uncover the spatiotemporal evolutionary patterns (Figure 3).

4. Characteristics of the Spatial Distribution of Ancient Architectural Heritage

4.1. Spatial Distribution Pattern of Ancient Architectural Heritage

To reveal the spatial distribution characteristics of existing ancient architectural heritage sites in southeastern Zhejiang, the “Kernel Density Analysis” tool in ArcGIS 10.8 was utilized to calculate the density of spatial distribution. Based on the calculation Formula (1), a bandwidth of 10 km was chosen, pixel size was set to 60, and the area unit was selected as square kilometers. This process generated a kernel density distribution map. The kernel density analysis map shows that ancient architectural heritage in southeastern Zhejiang is widely distributed with high spatial clustering and an uneven distribution pattern. It generally forms a spatial pattern known as the “Three Centers, Three Belts” (Figure 4). The “Three Centers” refers to three major high-density core areas: the Yuecheng and Keqiao areas in present-day Shaoxing (Zone I), the Haishu and Yinzhou areas in Ningbo (Zone II), and the Ouhai area in Wenzhou (Zone III). The kernel density values for these areas are all above 189.39. Further analysis reveals that secondary clusters (Zones I′, II′, and III′) gradually emerge from the high-density core areas, forming three belt-like derivative corridors. These corridors are: “Yuecheng District–Tiantai County–Huangyan District” (Belt I-I′), “Yinzhou District–Ninghai County–Tiantai County–Huangyan District” (Belt II-II′), and “Yongjia County–Ouhai District–Pingyang County–Taishun County” (Belt III-III′). These three belt-like derivative corridors form a “chain” that connects and constitutes the cultural heritage group in southeastern Zhejiang.

From the perspective of the “Point–Axis System” theory, the spatial pattern of the “Three Centers, Three Belts” serves as the foundation for the protection and development of ancient architectural cultural heritage in southeastern Zhejiang. In 2019, the Zhejiang government introduced the “Cultural Route with Tang Poetry as the Link”, where the “Belt I-I′” and “Belt II-II′” of the derivative corridors are located along the main and branch lines of the “Zhejiang Tang Poetry Route”. The “Belt III-III′” also overlaps with the branch route of the “Oujiang River Landscape and Poetry Route” (

Table 2. Derived corridors and their overlap with the “Poetry Road”.

High Agglomeration Area	Sub-Clustering Area	Ribbon Corridor	Overlapping with the Zhejiang “Poetry Road”
(Zone I) Yuecheng, Keqiao	(Zone I′) Shengzhou, Tiantai, Huangyan	(Belt I-I′) “Yuecheng–Tiantai–Huangyan”	It is located on the main line of the “Road of Tang Poetry in Eastern Zhejiang”
(Zone II) Haishu, Yinzhou	(Zone II′) Fenghua, Ninghai, Tiantai, Huangyan	(Belt Ⅱ-Ⅱ′) “Yinzhou–Ninghai–Tiantai–Huangyan”	It is located on the branch line of “East Zhejiang Tang Poetry Road”
(Zone III) Ouhai	(Zone III′) Yongjia, Lucheng, Ruian, Binh Duong, Taishun	(Belt Ⅲ-Ⅲ′) “Yongjia–Ouhai–Binh Duong–Taishun”	It is located on the branch road of “Oujiang Landscape Poetry Road”

). These derivative corridors are of significant importance for the study of cultural heritage context, hierarchical protection, and regional coordinated development in the region. At the regional development level, the ancient architectural heritage located within the belt-like corridors plays a strong role as a cultural carrier. It has regional synergistic advantages in terms of protection and development, exerting its agglomeration and diffusion effects.

4.2. The Relationship between the Spatial Distribution of Ancient Architectural Heritage and the Natural Environment

The southeastern region of Zhejiang, known as “Mountains and Seas”, is characterized by hilly terrain, crisscrossing rivers and canals, and numerous lakes and ponds. The unique natural environment influences the spatial distribution of architecture. By analyzing the topography, landforms, and hydrological characteristics, we can explore the correlation between the spatial distribution of ancient architectural heritage and the natural environment. The study of the spatial distribution characteristics of historical architectural cultural heritage and its correlation with the natural environment provides an important foundation and support for the delineation of subsequent cultural landscapes, cultural belts, and other related areas.

4.2.1. The Association with Topography and Landforms

Using the ASTER GDEM 30 m resolution digital elevation data from the Geospatial Data Cloud (http://www.gscloud.cn/, accessed on 10 October 2023), we imported the data into GIS and used the extraction tool to assign values to each point and calculate the results (

Table 3. Statistics on the elevation distribution of ancient architectural heritage in southeast Zhejiang.

Elevation /m	Pre-Qin Period /pcs	Qin Han to Tang /pcs	Song and Yuan Dynasties /pcs	Ming and Qing Dynasties /pcs	Since Modern Times /pcs	Percentage /%
Below 200 (Flat prototype)	2	6	36	166	20	85.82
200–500 (Hilly type)	0	0	1	23	1	9.33
500–1000 (Mountain type)	0	0	1	11	0	4.48
1000 or more (High prototype)	0	0	1	0	0	0.39
Average elevation /m	14 m	64 m	107 m	239 m	84 m	-

). This allowed us to obtain the elevation distribution of ancient architectural heritage in the southeastern region of Zhejiang (Figure 5). The analysis revealed that the main distribution range is in the plain areas below 200 m elevation, accounting for 85.82% of the total. As the elevation increases, the number of ancient architectural heritage sites sharply decreases, with only about 4.87% of them located in mountainous highland areas above 500 m, mainly concentrated in the Jingning area. Furthermore, with the passage of time, the average elevation shows a zigzag upward trend, reflecting changes in location selection and practical conditions during different historical periods.

We divided the slope into five categories and overlaid them with the ancient architectural heritage sites. Using spatial analysis tools, we extracted the number of ancient architectural heritage sites within different slope ranges and analyzed their distribution in relation to slope (

Table 4. Statistics on slope distribution of ancient architectural heritage in southeast Zhejiang.

Slope	Less Than 5%	5–15%	16–25%	26–35%	36–75%
Number of buildings/pcs	161	60	33	9	5
Percentage/%	60.07	22.39	12.31	3.36	1.87

, Figure 5). The results showed a similar pattern to the elevation distribution: as the slope increases, the distribution decreases. The majority of sites are located in flat areas with slopes below 15°, accounting for 82.06% of the total. When the slope is ≥15°, the number of ancient architectural heritage sites sharply decreases. Overall, the elevation distribution of ancient architectural heritage in the southeastern region of Zhejiang is mainly concentrated in plain areas and tends to be constructed in areas with relatively flat slopes.

4.2.2. The Correlation with Hydrological Features

Rivers are the foundation of human production and life, and they also play a significant role in influencing the spatial distribution of architecture. The southeastern region of Zhejiang is crisscrossed by rivers and lakes, and the distribution of ancient architectural heritage sites is closely related to them. Using the buffering tool in ArcGIS for hydrological analysis, we created buffer zones along the river system in the southeastern region at intervals of 500 m. Then, using the straight-line distance analysis tool, we summarized the proportion of different types of architectural heritage within each boundary zone [32] (

Table 5. Statistical distribution of the distance between historic architectural heritage in southeastern Zhejiang and rivers in different historical periods.

Distance from River/m	Pre-Qin Period /pcs	Qin Han to Tang /pcs	Song and Yuan Dynasties /pcs	Ming and Qing Dynasties /pcs	Since Modern Times /pcs	Percentage/%
Below 500	2	3	15	101	3	47.01
500–1000	0	1	6	52	2	23.13
1000–1500	0	1	7	22	7	13.81
1500–2000	0	1	4	9	4	5.97
Above 2000	0	0	7	16	5	10.07

). The analysis revealed that the majority (70.14%) of ancient architectural heritage sites are distributed within 1000 m of the rivers, with only 10.07% of them located more than 2000 m away from the rivers. The distribution along the rivers is evident. Among them, the Grand Canal water system in Shaoxing and Ningbo has the highest distribution of ancient architectural heritage, followed by the Wenzhou Plain located at the mouth of the Oujiang River and Feiyun River. In terms of historical periods, the statistical proportion of architectural heritage sites located within 500 m of rivers is as follows: during the Qin and Han dynasties, it accounts for 100%; from the Qin and Han dynasties to the Tang dynasty, it accounts for 50.00%; during the Song and Yuan dynasties, it accounts for 38.46%; during the Ming and Qing dynasties, it accounts for 50.50%; and since modern times, it accounts for 14.29%. Overall, there is a decreasing trend in the proportion, indicating that over time, the distance between architectural heritage and rivers has been increasing. This suggests that with the advancement of hydraulic and construction technologies, the reliance on water has been gradually reduced. Overall, the ancient architectural heritage in the southeastern region of Zhejiang is highly concentrated around water bodies, forming a coral-like pattern that follows the water (Figure 6).

5. The Temporal and Spatial Evolution Characteristics of Ancient Architectural Heritage

5.1. Ancient Architectural Heritage Added in Different Periods

There are a total of 268 ancient architectural heritage sites in southeastern Zhejiang. The construction periods of these sites are divided into five historical periods: the pre-Qin period, the Qin–Han to Tang period, the Song–Yuan period, the Ming–Qing period, and the modern period. The number of new additions to the ancient architectural heritage was recorded and summarized (

Table 6. Statistics of new ancient architectural heritage in southeast Zhejiang in different historical periods.

Category	Pre-Qin Period	Qin Han to Tang	Song and Yuan Dynasties	Ming and Qing Dynasties	Since Modern Times
The number of new ancient architectural heritage sites/pcs	2	6	39	200	21
Percentage of new additions/%	0.75	2.24	14.55	74.63	7.36

), and a time distribution graph depicting the evolution of the quantity was created. The analysis revealed significant differences in the number of new additions to the ancient architectural heritage during different historical periods, with a gradual-to-dramatic change, showing a “Λ” shaped pattern of variation. The majority of new additions to the ancient architectural heritage occurred during the Ming–Qing period, reaching 200 sites, accounting for approximately 73.53% of the total. The number of ancient architectural heritage sites before the Ming–Qing period and in the modern period was relatively small, accounting for only 26.47% of the total. Overall, the number of ancient architectural heritage sites in southeastern Zhejiang has shown a general increasing trend, with the growth rate gradually strengthening from the Song dynasty, reaching its peak during the Qing dynasty, and then returning to a steady growth trend.

The main reasons for this evolutionary characteristic are as follows: (1) Geographic conditions: Changes in the water environment were a crucial factor determining the rise and fall of culture in southeastern Zhejiang before the pre-Qin period. During the pre-Qin period, most coastal areas in southeastern Zhejiang were unsuitable for the formation and development of human settlements due to the influence of tidal waves. Therefore, construction activities were limited. In addition, temperatures between 20–30 °C are widely recognized as the most suitable range for mold growth [33], and most molds begin to germinate when the relative humidity reaches 80% [34,35]. The climate conditions in southeastern Zhejiang undoubtedly promote the decay of wooden structures in ancient buildings, making it increasingly difficult to preserve wooden structures as they age (2) Historical and cultural factors: Before the Sui and Tang dynasties, southeastern Zhejiang was referred to as a “barbarian land”, with fewer and lower-quality buildings. With the southward migration of the Song dynasty’s regime, southeastern Zhejiang experienced economic, cultural, and political development. For example, during the Southern Song dynasty, the Wenzhou Prefecture had the highest number of successful candidates in the imperial examination, with 1107 individuals, accounting for 19.2% of the total in Zhejiang. The prosperity of society brought vitality to construction activities, and the number and distribution of large houses paralleled the distribution of successful examination candidates [28], even the first book on architecture in China, the Mu Jing (Timberwork Manual), was published. In the middle and later periods of feudal society in China, economic prosperity, social stability, and the peak of technological development provided comprehensive support for construction activities. However, after the outbreak of the Opium War, the southeastern Zhejiang region was plagued by continuous warfare [36], and thus the increase in construction was forced to slow down.

5.2. Spatial Distribution Characteristics of Ancient Architectural Heritage Added in Different Periods

By using the nearest neighbor analysis method, the spatial distribution of aggregation and dispersion among various research samples can be effectively quantified. Based on the calculation of Formula (2), the nearest neighbor indices (

Table 7. Statistics of the nearest neighbor index of ancient architectural heritage in southeast Zhejiang in different periods.

Historical Period	Theoretical Nearest Distance/km	Actual Nearest Distance /km	Nearest Exponent R	Z-Score	p-Value	Spatial Distribution Type
Pre-Qin period	0.2439	237.9351	975.5706	2636.6908	0.0000	Significantly dispersed
Qin Han to Tang	29.5843	45.3475	1.5328	3.0580	0.0022	Dispersed
Song and Yuan dynasties	13.1846	19.6342	0.6715	−3.9245	0.0001	Agglomeration
Ming and Qing dynasties	9.6668	5.6383	0.5833	−11.2748	0.0000	Significant agglomeration
Since modern times	24.1446	23.6462	0.9794	−0.1810	0.8564	Uniform

) of ancient architectural heritage in southeast Zhejiang were calculated for different time periods, and a diagram illustrating the analysis of nearest neighbor distances was generated (Figure 7). The results indicate that the pre-Qin period (R = 975.5706) and the Qin-Han to Tang period (R = 1.5328) had a nearest neighbor index greater than 1, indicating a dispersed distribution of newly added ancient architectural heritage. The Z-value for the pre-Qin period was 2636.6908, suggesting a significant dispersed pattern during that time. From the Song–Yuan period to the Ming–Qing period, all the nearest neighbor indices were not greater than 1, indicating an aggregated pattern. Among them, the Ming–Qing period had the smallest R-value (0.5833), and the Z-value reached −11.2748, indicating the highest degree of aggregation of newly added ancient architectural heritage. In modern times, the R-value was 0.9794 (p = 0.8564), approaching 1, indicating a more uniform distribution of newly added ancient architectural heritage during that period. Overall, influenced by historical factors, the number of newly added ancient architectural heritage before the Tang dynasty was relatively low, with a lower degree of aggregation. However, starting from the Song dynasty, newly added ancient architectural heritage began to aggregate, and the degree of aggregation gradually strengthened. This trend only slowed down with the end of feudal society.

5.3. Spatial Structural Analysis of Historical Architectural Cultural Heritage in Southeastern Zhejiang

Analyzing the structural characteristics of the spatial distribution of historical architectural cultural heritage at different periods helps lay the groundwork for subsequent micro-level studies on the homogeneity and heterogeneity of such heritage. This, in turn, facilitates the implementation of layered and graded preservation and development strategies. By utilizing the kernel density analysis tool with a search radius of 25 km, density distribution maps of newly added historical architectural sites at different time intervals were generated.

5.3.1. Spatial Structure in the Pre-Qin Period

During the pre-Qin period, the distribution of architectural heritage was primarily concentrated in hilly areas, with a dispersed spatial distribution and little correlation (Figure 8). However, within the cultural geographical context, the water environment was a key factor determining the rise and fall of prehistoric culture in southeast Zhejiang [37]. As mentioned in the “Gouzhuo Zhi” chapter of the Book of Han, “After a period without harm, people gradually built houses, which eventually formed settlements”. The formation, location, and development of settlements were closely related to the natural environment. During the Paleolithic Age, the mountainous areas had abundant freshwater resources, and human survival relied on the mountains. However, they needed to avoid dampness and flood disturbances in their settlements, thus staying away from low-lying areas near rivers and lakes. With the gradual emergence of agricultural civilization, the impact of tidal waves and sea invasions remained significant. The coastal plain areas of Zhejiang were often submerged by seawater or turned into marshes, which were unsuitable for human habitation [38]. On the other hand, the regions of Zhuji, Ruian, and other areas in southeast Zhejiang were mostly basins with higher terrain and relatively advantageous natural conditions. As recorded in Volume Four of the Wuyue Chunqiu, “They cultivated the land along the hills and hunted birds and deer for food”. It was through this process that settlements were formed and developed during the pre-Qin period.

5.3.2. Spatial Structure from the Qin and Han Dynasties to the Tang Dynasty

During the Qin-Han to Tang period, the distribution density of ancient architectural heritage was relatively uniform, with a concentration in the present-day Ningbo area (Figure 9). During the Qin-Han period, with the improvement in land reclamation and water conservancy facilities, the spatial density of architectural heritage in the Ningbo–Shaoxing Plain began to increase [39]. Excavations of Eastern Han dynasty tombs in the Ningbo area have provided evidence of advanced brick and tile production, with the use of “brick arches” in architectural construction. During the Chen and Sui dynasties, the earliest Buddhist sect in China was established on Mount Tiantai in Taizhou. According to the “Overview of Longquan Buddhism” “Zhikai established the earliest Buddhist sect in China, Tiantai sect, on Mount Tiantai in Zhejiang, which had a significant influence on Zhejiang Buddhism and even Buddhism nationwide”. According to the “Collected Study of Tang and Five Dynasties Buddhist Temples”, Buddhist temples were already widespread along the poetry route in Zhejiang during the Tang dynasty and the Five Dynasties period. Buddhist temples served as important nodes along the Tang poetry route in southeast Zhejiang [40]. The “Jiading Chicheng Records” mentioned 98 Zen temples in Linhai and 68 temples in Huangyan during that time. Prior to the Wuyue Kingdom, the development center of Buddhism in Zhejiang was in the Ningbo and Taizhou areas, with Ningbo serving as an important port for the dissemination of Buddhist culture [41]. Some temple and pagoda architectural heritage has been preserved, including the Tianning Temple Pagoda in Ningbo, which was built during the Tang Xiantong period (860–873 AD). It is a small-scale brick-structured square pagoda and the only surviving Tang pagoda in Zhejiang. The density structure of ancient architectural heritage from the Qin-Han to Tang period reflects the complementary relationship between agricultural development and Confucianism, Buddhism, and Taoism, combined with the cultural achievements produced by the landscape of southeast Zhejiang.

5.3.3. Spatial Structure in the Song and Yuan Periods

During the Song and Yuan dynasties, the spatial distribution density of ancient architectural heritage was significantly concentrated in the surrounding areas of the present-day Ningbo–Shaoxing Plain and Wenzhou Coastal Plain, with less distribution in the central and southwestern mountainous regions (Figure 10). Starting from the Five Dynasties period, the southeastern part of Zhejiang received attention in terms of border defense and stability, leading to a flourishing population in the region. As recorded in Chen Liang’s Longchuan Collection, “The people prospered day by day, making the southeast prominent”. After the Southern Song dynasty established its capital in Lin’an, the total population of the seven counties in the Ningbo–Shaoxing Plain reached 1.5 million. Water conservancy facilities evolved from initially supplying local livelihood and agricultural water needs to performing diversified functions such as regulating the overall water environment of the plain, canal transportation, and traffic [42]. Agricultural production in the Wenzhou Coastal Plain also experienced development. According to Qianlong’s “Wenzhou Prefecture Records”, it began during the late Tang dynasty and the Five Dynasties period (907–978 AD), when the people of Wenzhou built embankments to resist saltwater intrusion and to control the rivers for irrigation purposes. With the development of traditional crafts such as shipbuilding and porcelain making, both Ningbo and Wenzhou became important ports for foreign trade during that time. The architectural treatise of the Northern Song dynasty, Yingzao Fashi emerged and incorporated many local practices from the southeastern part of Zhejiang, reaching a high level of architectural technology. The density structure of ancient architectural heritage during the Song and Yuan dynasties reflects the changes in human living and production conditions, gradually transitioning from hilly areas to the plains and transforming the plains.

5.3.4. Spatial Structure in the Ming and Qing Periods

During the Ming and Qing dynasties, there was further development based on the foundation of the Song and Yuan periods, resulting in the highest number of newly added ancient architectural heritage in history. Core distribution areas were formed in Yuecheng, Ningbo, Tiantai, and Wenzhou, while secondary aggregation areas emerged in Zhuji, Shengzhou, Ninghai, and Huangyan. There was also a trend of expansion towards the central and southwestern mountainous regions (Figure 11). With the continuous and rapid socioeconomic development during the Ming and Qing dynasties, accompanied by a significant increase in population, numerous prosperous towns emerged in the southeastern part of Zhejiang, such as Jiangkou Town and Zhang’an Town in Yongjia. The architectural types became diverse, including temples, libraries, gardens, and archways. Since the mid-Ming period, when the court allowed ancestral temples to be built by the common people, the development of ancestral temple architecture in southeastern Zhejiang progressed rapidly. Examples include the Sanmen Ancestral Temple Group in Taizhou and the Nanxi River Ancestral Temple Group. From the Ming dynasty onwards, the use of bricks in architecture became common, which promoted the development of brick construction techniques. The addition of ancient architectural heritage during the Ming and Qing dynasties laid the foundation for the distribution pattern of ancient architectural heritage in the southeastern part of Zhejiang that followed.

5.3.5. Spatial Structure in Modern Times

Since modern times, there have been only 20 newly added ancient architectural heritage sites. From the figure, it can be observed that the core distribution areas have not undergone significant changes, and the spatial distribution has generally maintained the pattern from the Ming and Qing dynasties (Figure 12). In modern times, southeastern Zhejiang became a frontier stronghold of the modern revolution, resulting in a sharp decline in the construction of new buildings. The remaining ancient architectural heritage today mainly consists of revolutionary cultural relics such as the former residences of Lu Xun and Qiu Jin, which emerged after the Self-Strengthening Movement. Most of these buildings are still in use today. The historical architectural and cultural heritage of this period highlights the arduous struggles that took place in the southeastern Zhejiang environment and holds strong educational significance for future generations. It provides a foundation for the integrated protection of tangible and intangible cultural heritage.

6. Conclusions

This study lays the foundation for the future regional coordinated development, graded protection, and lineage research of architectural cultural heritage in southeastern Zhejiang. It provides a basis for the spatial integration, categorization, and preservation of natural landscape features in a series of cultural heritage corridors, such as the Tang Poetry Road, the Eastern Zhejiang Coastal Defense Road, and the Red Revolution Road in Zhejiang province. Consequently, it enables the sustainable development of the cultural value of architectural heritage in the region. The conclusions are as follows:

(1)

The ancient architectural heritage sites in southeastern Zhejiang are primarily concentrated in the core areas of Yucheng and Keqiao in present-day Shaoxing, Haishu, and Yinzhou in Ningbo, and Ouhai in Wenzhou. The kernel density values for these areas are all above 189.39, indicating high concentration. Three heritage corridors have been identified: “Yucheng District–Tiantai County–Huangyan District”, “Yinzhou District–Ninghai County–Tiantai County–Huangyan District”, and “Yongjia County–Ouhai District–Pingyang County–Taishun County”. These corridors, together with the overall spatial distribution pattern of “three cores and three belts”, have been formed. At the subsequent regional development level, the heritage buildings in these belt-shaped corridors have a clustering effect and possess the advantage of regional linkage in terms of protection and development. Targeted sustainable development strategies can be proposed accordingly.

(2)

The spatial distribution of ancient architectural cultural heritage sites in southeastern Zhejiang is highly influenced by the topography and landforms. With the transformation of water resources and the improvement in productivity, the degree of this constraint has gradually decreased. The average elevation has risen from 14 m in the pre-Qin period to 239 m in the Qing dynasty. The spatial distribution ultimately presents a coral-shaped pattern that follows the water flow. Approximately 47.01% of the buildings are located within 500 m of water. It can be observed that there is a strong correlation between the overall cultural heritage structure of the region and the natural environment. Therefore, in the subsequent development process, it is important to consider the correlation between the overall spatial distribution of ancient architectural cultural heritage and the natural environment in the region. This has significant implications for the delineation of cultural heritage landscapes, cultural corridors, and other areas in southeastern Zhejiang in the future.

(3)

During different historical periods, the number of newly added architectural heritage sites in southeastern Zhejiang exhibits a characteristic “Λ” shape in terms of changes. The Ming and Qing dynasties saw the highest increase, with 200 additions, accounting for approximately 73.53% of the total. Influenced by factors such as water resource reforms, immigration policies, administrative changes, and cultural ideologies, the spatial distribution gradually shifted from a dispersed pattern to a clustered one. From the Song and Yuan dynasties to the Ming and Qing dynasties, the nearest neighbor index did not exceed 1, indicating a state of clustering. Among them, the Ming and Qing dynasties had the smallest R-value (0.5833) and the Z-value reached −11.2748, indicating the highest level of clustering for newly added ancient architectural heritage. From the perspective of heritage preservation, this provides a reference for the subsequent research on the lineage of architectural heritage in southeastern Zhejiang, further enhancing the social attributes of these heritage sites and promoting the inheritance and continuity of regional culture.

Carrying out the protection and utilization planning of regional historical architectural cultural heritage and coordinating the overall relationship between the regional natural landscape and cultural characteristics is of significant importance for the continuity of regional culture and landscape features. This study provides scientific support for the subsequent comprehensive protection, management, and planning of cultural heritage in the area. However, due to limited resources and time, further in-depth research is still needed. (1) The data used in this paper are limited and mostly derived from nationally and provincially designated key cultural heritage sites. The data samples need to be expanded to obtain more accurate research results. (2) The spatial distribution of cultural architectural heritage in southeastern Zhejiang is not only influenced by factors such as topography and landforms, as analyzed in this study, but also closely related to factors such as water resource reforms, immigration policies, administrative changes, and cultural ideologies. Although the article mentions these factors, a more detailed analysis is still needed, which will be a key focus of future research. (3) Architectural heritage in southeastern Zhejiang is not a singular phenomenon. It requires interdisciplinary analysis based on a broader range of environmental factors. There are various influencing factors on the distribution of historical architectural heritage in different historical periods, and each factor needs to be examined in detail.