1. Introduction
Tianjin is a significant hub for China's modern industrial evolution, hosting historical sites of significant industrial heritage, such as the former Beiyang Fleet Dockyard and the Mint. This city has birthed pivotal achievements in the industrial sector of New China, including the first domestically-made bicycle and wristwatch, affirming its status as one of the country's venerable industrial strongholds [
1]. Therefore, Tianjin's industrial heritage exemplifies national representativeness and serves as a tangible repository of the city's industrial history [
2]. In response to the "14th Five-Year Plan," [
3] Tianjin has enacted a suite of policies, notably the "Tianjin Industrial Heritage Management Measures," aimed at enhancing the preservation and enduring legacy of these priceless assets. These efforts are part of a broader initiative to continually refine the legal and regulatory frameworks about Tianjin's industrial heritage, significantly enhancing the protection and adaptive reuse of the city's industrial relics.
Current research demonstrates that many scholars have delved deep into Tianjin's industrial heritage, examining its spatial organization, functional amenities, structural layout, and distinctive features, including the dynamism inherent in Tianjin's industrial heritage [
4], the conceptualization and realization of Tianjin's industrial heritage corridor [
5], the evolutionary narrative of Tianjin's modern industrial endeavors [
6], the inventive repurposing of Tianjin's industrial heritage [
7], the development of a comprehensive database encapsulating Tianjin's industrial heritage [
8], and the creation of robust regulatory measures for preserving and managing Tianjin's diverse industrial heritage [
9]. These perspicacious studies have furnished invaluable insights, proving instrumental in the ongoing efforts to preserve and leverage Tianjin's rich industrial heritage. However, current research also shows that the approvals for the preservation and utilization of Tianjin's industrial heritage primarily depend on policy orientations, refining regulations, and suggesting policy amendments [
10,
11]. As such, this condition neglects the crucial planning and design aspects that consider the temporal-spatial structure of the industrial legacy [
12,
13]. Therefore, There exists a gap in examining the intricate links between the distribution of Tianjin's industrial heritage and the city's historical and spatial context. Moreover, there has been insufficient use of existing research on the development of Tianjin's industrial heritage corridor and the impact of environmental factors on the current development of industrial heritage.
As efforts to preserve and leverage Tianjin's industrial heritage evolve, on-site surveys of specific industrial heritage sites underscore the multifaceted influences shaping their preservation and utilization, resulting in notable regional and structural differences, as shown:
1) Due to the diverse historical epochs of industrial heritage construction, discernible regional disparities in their preservation and utilization have emerged. For example, industrial legacies dating from the modern era to the inception of the People's Republic of China are typically designated as heritage conservation units, either actively maintained or in dormant states. Subsequently, while certain industrial heritage sites have evolved to fulfill their original functions or adopted new roles, others have been neglected, facing imminent risk of deterioration.
2)Urban spatial planning has led to distinct variations in the environments of industrial heritage sites. Notably, some sites located along North Jiefang Road and the banks of the Haihe River benefit from favorable environmental conditions. In contrast, some are situated in secluded neighborhoods or rural areas, experiencing restricted accessibility and less conducive spatial environments.
3) Local economic and industrial planning has fostered structural disparities in the strategies for developing and utilizing industrial heritages: In Tianjin, the repurposing of industrial heritage mainly focuses on functions like museums, industrial parks, and government services, according to standardized preservation practices.
4) Social and environmental factors play a pivotal role in shaping regional disparities in the condition of industrial heritage. From structural integrity to interior and exterior spaces and the overall site environment, conditions vary significantly, ranging from severe neglect and damage to meticulous preservation. These discrepancies often align with a region's geographic location, GDP, and related variables. Typically, regions with superior conditions exhibit more robust conservation efforts, while others struggle to achieve effective preservation.
The mentioned differences are becoming evident in the activities of preserving and utilizing Tianjin's industrial heritage. These efforts encounter many hindrances stemming from heritage construction's temporal and spatial characteristics and the nature of production. This constraint presents challenges for industrial heritage, consequently impeding urban development. Therefore, striking a harmonious balance between preserving and adapting industrial heritage to become a focal point of urban growth and city development has emerged as an urgent imperative. This paper aims to address this problem through a comprehensive examination of Tianjin's industrial heritage. This paper elucidates the temporal and spatial dynamics, as well as the typological characteristics of the heritage distribution, by employing geospatial analysis techniques provided by Arcgis (a Geographic Information System software), such as kernel density analysis, standard deviation ellipse analysis, centroid shift models, and conventional mathematical statistics. Furthermore, influential factors and explanatory power behind the distribution disparities of industrial heritage resources are identified to unveil the spatiotemporal distribution patterns and inherent laws of Tianjin's industrial heritage from a geographical and historical perspective. In the last, theoretical suggestions are proposed to help Tianjin's industrial heritage navigate its difficulties, providing a research base for the conservation and creative reuse of industrial heritage resources in Tianjin.
2. Research Method
2.1. Data Collection
This study examines the industrial heritage of Tianjin as cataloged in the "National Industrial Heritage List" and "China Industrial Heritage Protection Catalog," emphasizing the period from Tianjin's historic opening to the dawn of China's reform era (1860-1978). This exploration encompasses a variety of industrial sectors, including light manufacturing, print production, textile industries, transportation, communication equipment, and electronics manufacturing. This exploration focuses on the physical remnants, such as industrial sites and buildings and their associated structures. Moreover, the spatial vector data utilized in this analysis are sourced from the National Basic Geographic Information System and the National Administrative Division Information Query Platform. The data on the main flow of the Haihe River and its tributaries are confined to the administrative boundaries of Tianjin. Furthermore, the study incorporates data obtained from official statistical records on variables affecting the distribution of industrial heritage within Tianjin, including transportation, economic factors, and demographic details.
2.2. Research Methods
This study thoroughly investigates the distribution patterns and underlying historical causes of Tianjin's industrial heritage utilizing ArcGIS as the primary analytical tool, complemented by traditional mathematical statistics and supported by corroborative historical evidence. The following illustrates the methods used in this paper[
14].
1)Kernel density estimation. This method quantitatively examines the spatiotemporal distribution and clustering characteristics of Tianjin's industrial heritage. Within the framework of Geographic Information Systems, this analysis method primarily evaluates and portrays the density and focal concentration of resource elements within a specified spatial boundary [
15]. The foundational function as shown:
h>0 denotes the bandwidth, n is the total number of industrial heritage, and (x-xi) denotes the distance from the valuation point x to the industrial heritage point.
2)Gravity Migration Model. This study employs the centroid migration model to trace the spatial evolution of Tianjin's industrial heritage throughout its historical timeline. This model serves as a robust spatial analysis tool, adept at unraveling the dynamic patterns of regional resources as they shift across time and space [
16]. The foundational function as shown:
(xi, yi) is the center of geographical coordinates of each administrative unit in Tianjin, and mi is the value of industrial heritage in each administrative unit in each historical period.
3)Concentration Index. The concentration index shows a nuanced understanding of various resource elements' distribution and specialization levels within designated areas. This paper employs the Lorenz Curve to dissect and delineate the structured characteristics of Tianjin's industrial heritage according to type, offering a precise visualization of resource distribution and thereby enhancing insight into structural nuances [
17]. The foundational function as shown:
C is the sum of the cumulative percentages of industrial heritage types; M is the sum of the cumulative percentages when the distribution is fully pooled; K is the sum of the cumulative percentages when the distribution is fully averaged. The value range is [0, 1], and a larger value of I indicates a higher degree of centralization in terms of type.
4)GeoDetector. The geodetector method is applied to assess how natural and social environments influence the distribution of Tianjin's industrial heritage. By calculating and analyzing the q-value within the geodetector, this approach identifies which factors explain the spatial distribution of Tianjin's industrial heritage significantly, thereby facilitating a deeper understanding of its distribution patterns and inherent characteristics [
18]. The foundational function as shown:
Nh and σh2 are the number and variance of industrial heritage, respectively; Nh and are the value and variance of the influencing factors of category h; L is the number of classifications of the influencing factors of category h. Not that the domain of q is [0, 1], and the larger the value of q is, the stronger the explanatory power of the indicator on the distribution of the number of industrial heritage.
4. Conclusions
4.1. Objective Law
This investigation employs spatial geographic analysis and statistics to thoroughly examine and synthesize the temporal evolution, spatial configurations, and typological attributes of the 112 industrial heritage sites in Tianjin. The conclusions drawn from the study delineate the following patterns:
1)Time situation
The origins of Tianjin's industrial heritage can be traced back to the industrial activities initiated by various foreign powers following the opening of the port in 1860, catalyzing the city's modernization efforts. Over time, the number of industrial heritage sites in Tianjin has exhibited an overall growth, punctuated by periodic fluctuations. Historically, transportation-related industrial heritage predominated from 1860 to 1949. However, after 1950, the focus shifted towards mechanical industrial heritage and architectural heritage buildings. A notable turning point occurred from 1912 to 1936, during which the count of industrial heritage sites experienced fluctuations—a decline followed by a subsequent rise. Examining the socio-historical contexts of different periods, it becomes evident that the distribution of Tianjin's industrial heritage closely mirrors the political landscape and urban development of each era [
36]. This correlation explains the regional disparities in the conservation and utilization of industrial heritage, rooted in distinct historical construction phases.
2)Spatial situation
Tianjin's industrial heritage exemplifies the typical distribution traits of a coastal city's industrial legacy, primarily following linear patterns along the city's river systems and converging in the central urban district. Additionally, parts of this heritage are sporadically scattered as isolated points across the northern mountainous regions and other suburban counties. Tianjin's industrial heritage is characterized by a strong reliance on transportation corridors. The distribution of these heritage sites demonstrates a relatively weak association with the natural characteristics of rivers but a pronounced correlation with their navigational attributes. Within the city's boundaries, the distribution of industrial heritage is notably uneven: a dense concentration is observed in the central urban area, while the Binhai New Area and Jinghai District, though hosting simpler varieties of heritage types, contain a larger number of sites; other areas experience sparse distribution or complete absence. In Tianjin's urban planning, development, and renewal activities, a practical issue has gradually emerged: the surrounding environmental space often fails to meet the planning and development needs when updating the stock of industrial heritage. These issues have a bidirectional influence on the spatial distribution pattern of Tianjin's industrial heritage. On the one hand, the modern urban spatial structure of Tianjin is the primary reason for the linear distribution pattern of industrial heritage. On the other hand, the current efforts to update Tianjin's industrial heritage stock face developmental challenges due to the differentiated geographical spatial environments.
3)Distribution type characteristics
The distribution of industrial heritage types in Tianjin features a distinctly dispersed structure. Transportation-related heritage ranks as the predominant category, followed by manufacturing and communications heritage. In contrast, water and waste management and refining heritage occupy relatively minor positions. Significant clusters of transportation and chemical industrial heritage are found in Tianjin's central urban area, the Binhai New Area, and Jinghai District. Manufacturing heritage primarily concentrates in the central urban area and the Xiqing and Jinghai districts, while other types are variably distributed across Tianjin's districts. The nature of industrial heritage mirrors the scope of historical industrial activities and shapes the internal spatial systems and structures of these sites. A significant challenge in the renewal of industrial heritage stock is the conflict between new business forms and existing heritage spaces. This dynamic is critical for fostering positive development within these spaces, preserving their cultural legacy, and achieving their renewal.
4)Influencing factors and explanatory power
The social environment exerts a more pronounced influence than the natural environment on industrial heritage. In analyzing these effects, the hierarchy of impact is as follows: transportation factors > economic factors > population factors > cultural and educational factors. Within the social context of industrial heritage sites, obstructed transportation networks, isolated populations, sluggish economic growth, overlooked cultural industries, and bottlenecks in urban planning and development are identified as the primary reasons for the significant discrepancies in the protection and utilization of Tianjin's industrial heritage. These factors also pose substantial challenges that could impede the future development of Tianjin's industrial heritage.
4.2. Policy Recommendations
Tianjin's industrial heritage stands as a testament to the city's journey toward modernization and serves as a crucial material representation of its regional culture. Drawing from the identified distribution patterns and causal analysis of Tianjin's industrial heritage, the following policy recommendations are proposed to navigate the future protection and utilization of these invaluable assets:
1) Culture and History: The integration of industrial heritage with historical tapestry fosters the preservation of regional industrial cultural heritage, enhances the quality of public cultural services, and stimulates the collaborative development of cultural tourism, thereby enhancing the overall cultural tourism experience.
Drawing from the temporal distribution characteristics of Tianjin's industrial heritage, its development and utilization have been harmonized with the historical narrative of the city's modern industrial evolution, giving rise to distinctive industrial tourism initiatives like the "Modern Industrial Historical Routes" and "New China Industrial Construction Routes." These initiatives are designed to bolster the "See Modern China through Tianjin" tourism brand, conserve the industrial legacy, and establish a groundwork for the differentiated protection and utilization of industrial heritage [
37]. This strategy fosters a development model that combines continuity with diversity across different epochs. Incorporating the spatial distribution characteristics of Tianjin's industrial heritage, which should be seamlessly woven into the planning and construction scope of the Haihe Cultural Belt, emphasizing the preservation of cultural heritage, delving deep into the cultural essence, all the while crafting a unique urban image and nurturing a vibrant cultural atmosphere [
38].
2) Environmental Space: Refining urban spaces and transportation networks contributes to enhancing the environmental ambiance of industrial heritage sites, enriching public service offerings, and advancing high-quality urban development.
Refining urban spaces and transportation networks contributes to enhancing the environmental ambiance of industrial heritage sites, enriching public service offerings, and advancing high-quality urban development [
39,
40,
41,
42,
43,
44]. Critical to this effort is bringing industrial heritage sites that urgently need protection yet are currently unused and unprotected into the conservation framework. Guided by the spatial planning strategies of "Compact and Vibrant Jin City" and "Innovative and Livable Bin City," it is crucial to tailor and enhance the environmental conditions of these sites appropriately [
45]. In Jin City, it is essential to enhance the environments of industrial heritage sites and improve transportation accessibility, repurposing underutilized areas into reserves for high-quality development. In Bin City, expanding spatial boundaries and improving surrounding public services are recommended, setting the stage for urban development and fostering high-quality growth in the region [
46].
3) Sustainability: To align with the optimization of the industrial structure, it is important to harness the positive impact of the cultural industry, foster social collaboration, and promote urban prosperity and development.
Since the launch of the "14th Five-Year Plan," Tianjin has strategically targeted the functional orientation of "one base and three zones," achieving significant strides in optimizing its industrial structure and strengthening its economic foundation[
47]. Utilizing optimization strategies such as "dual belts aggregation, twin cities optimization, intelligence valley upgrading, and group linkage," the city has integrated service industries, revitalized industrial remnants, and exploited the unique spatial features of various types of industrial heritage to refine spatial configurations[
48]. This strategy has involved expanding methods of industrial heritage protection and utilization[
30], promoting differentiated development in this area, and thus establishing a multidimensional framework for the protection and utilization of Tianjin's industrial heritage[
49]. Moreover, the city has optimized the distribution of cultural resources, building upon industrial heritage to foster cultural industries, encouraging community engagement in public cultural services, enhancing public cultural service mechanisms, supporting community cultural activities, fully leveraging social resources, and utilizing demographic dynamics to activate industrial heritage [
50,
51,
52]. This strategy includes creating cultural activity platforms that are both popular and accessible, with an emphasis on integrating science, education, and culture with industrial heritage[
53], continually injecting new vitality into the city.