The strategies of overall spatial regulation for rural area: based on Shanghai’s experience

Under the spatial planning system, the spatial regulation of rural areas faces the basic requirements of "comprehensive coverage of regulation objects, refined regulation measures at each level, and regulation level corresponding to the administrative power". Since the reform and opening up, Shanghai has gradually developed from the "single administrative area" regulation of rural construction spaces to the "comprehensive regulation" of three types of rural spaces. The regulation system consisting of three levels has been formed, including village layout planning, suburb unit planning, and village design. Comprehensive coverage of regulation objects and refined regulation measures at each level have been realized. However, there are also problems such as the weak regulation of the ecological space, the need to improve the level of fine regulation andexcessive restrictions on regulation contents at the town level. Based on the analysis of Shanghai's successful experience and existing problems, the zoning, grading and classification strategy for the spatial regulation in entire rural administrative areas is proposed. Refine the regulation objects based on "spatial zoning-usage unit-plot polygon", define regulation tasks of all levels as per "structural regulation-usage regulation-element regulation"; formulate classified regulation measures according to "transmission of basic element level by level, classified overlying of additional elements".


Introduction
Opinions of the CPC Central Committee and the State Council on Establishing the System of Territorial and Spatial Planning and Supervising its Implementation (hereinafter referred to as Opinions) constructed the overall framework of China's spatial planning, and the Notice of the Ministry of Natural Resources on Strengthening Village Planning to Promote Rural Revitalization made clear the legal status of village planning as a detailed planning in rural areas.It should be noted that rural areas are a vast and complex system,and there are different levels of regulation needs such as macro needs, meso needs and micro needs (Ge & Hua, 2010;Kuai & Liu, 2010;Zhou & Yu, 2014), and village planning cannot cover all.Based on the analysis framework of "regulation objects, regulation measures, and regulation levels", this paper combs the basic requirements of the spatial planning system, analyzes the evolution characteristics and existing problems of spatial regulation in rural areas of Shanghai, and puts forward the spatial regulation strategy in entire rural administrative areas.
of territorial use should be extended to all natural ecological spaces.In 2019, "Opinions" once again emphasized coordinating the layout of ecological, agricultural, urban and other functional spaces, and improved use control.It can be seen that the original intention of the state to promote the control of territorial spatial use of the entire administrative area comes down in one continuous line and is constantly refined.

Comprehensive coverage of regulation objects
It is the foundation of space governance to implement the control of territorial spatial use of the entire administrative area.In the wide-area rural territorial spaces, the village is only one of the "points".In the past, rural planning focused more on the "point" for the "administrative area", focusing on the village construction space and the regulation of agriculture and ecological space being extensive, which led to the omission and lack of planning regulation in rural areas, and failure to effectively realize the comprehensive use regulation of rural territorial space (Zhang et al., 2014a(Zhang et al., , 2014b)).Therefore, we must start from the wide-area rural territorial spatial pattern, coordinate the different needs of village construction, agricultural production and ecological protection, optimize the three spatial patterns of construction, agriculture and ecology, coordinate the formation of non-overlapping ecological protection boundaries, permanent basic farmland protection lines, village centralized construction boundaries and other control lines, refine and coordinate the relationship among these spatial elements, and realize the comprehensive coverage of spatial regulation in rural areas.At present, China has gradually established a land use control system covering increment and stock for rural construction space, and has a clear regulation method for cultivated land in agricultural space, while the regulation of other agricultural space and ecological space remains relatively extensive (Deng et al., 2020), so it is necessary to refine the regulation contents of agricultural space and rural ecology.

Refine regulation measures level by level
On the one hand, construction, agriculture and ecological spaces have significant differences regarding land property rights (Tian et al., 2015), spatial organization forms and environmental characteristics (Luo et al., 2016;Geng et al., 2019), governance model (Zhang et al., 2014a(Zhang et al., , 2014b) ) and other aspects, and the regulation measures need to combine various spatial characteristics and highlight pertinence (Zhao et al., 2015).On the other hand.due to the diversity, complicacy and functional complexity of space resources, space regulation needs to combine different levels of administrative powers of government agencies and adopt diversified regulation measures based on the principle of "only approving what one has authority to approve".It is necessary to strengthen the effective connection and transmission between various planning, ensure the implementation of spatial regulation, and realize the bottom line constraint role of rural spatial planning; it is also necessary to improve the efficiency and adaptability of spatial regulation, and reserve space for the uncertainty of rural social development.Therefore, the connection of different regulation measures is the key to the effective coverage and implementation of rural spatial planning.It is necessary to formulate hierarchical and classified regulation measures for rural space, not only to clarify the spatial constraint indicators and boundaries, decomposed and refined requirements of regulation at all levels, and to improve the vertical transmission mechanism of planning, but also to clarify the requirements of various flexible indicators, so that the responsible subjects at all levels can formulate rural planning according to the actual situation and needs of rural development, and highlight the key points and characteristics of rural areas (Zhang, 2018).

Urban and rural planning legislation in the twenty-first century
As an important means of national spatial governance, spatial planning needs to clarify the authority-responsibility relationship of governments at all levels in the spatial planning system, and reasonably determine the scope of the upper and lower level administrative powers and manage the authority-responsibility relationship.In the past, the deep-seated reason for the conflicts among various spatial planning was the result of a series of games caused by the vertical incoherence and the failure to sort out the administrative power relationship (Lin et al., 2018).According to the administrative power relationship between different governments, the Opinions divide spatial planning into "five levels and three categories", and require that the formulation and regulation of spatial planning should be carried out according to the principles of "the organizer of the formulation should be the organizer of the implementation", "the approver should be the supervisor" and "only approving what one has authority to approve".The planning management logic of "a government at a certain level has only the administrative power at this level" has been deeply rooted in the hearts of the people.The establishment of natural resources department has basically solved the problem of overlapping planning management among horizontal departments, but there is still a lack of reasonable definition of vertical administrative powers of planning at all levels (Zhang & Liu, 2018).Therefore, for the spatial regulation of rural areas, it is necessary to study the boundaries of planning authorities and responsibilities of government agencies at all levels, select planning regulation elements, and establish a multi-level planning regulation system based on administrative powers (Sun & Zhang, 2017).
3 Evolution characteristics and reflection on problems of spatial regulation in rural areas of Shanghai 3.1 "Single administrative area" regulation of rural construction space

General regulation of villagers building houses
spontaneously (1978)(1979)(1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990) In 1978, the general line of reform and opening-up was determined, and the income of villagers increased continuously, which suppressed the release of villagers' demand for building houses in recent 30 years.1).However, the pits and ponds in front of and behind houses are filled by villagers for building houses, which encroaches on the ecological space of villages.At the same time, the detailed rules stipulate that the land for villagers to build houses should be controlled at 12-20 m 2 per capita, and the estimated per capita housing area should not exceed 30 m 2. However, due to the lack of effective regulation measures, the building area of villagers far exceeds the detailed rules.According to statistics 1, the per capita living area of rural houses in the whole city increased from 16.75 m 2 in 1978 to 42.01 m 2 in 1990.' concentrated building (1990-2011) In the 1990s, the disadvantages of scattered construction of houses by villagers on the basis of the original natural villages began to appear.The scattered layout of residential areas is not conducive to the configuration of infrastructure.and it is difficult to meet the needs of large-scale agricultural production.For this reason, the Shanghai Municipal Government put forward the "Three Concentrations" strategy of "residential areas concentrated in urban areas, industries concentrated in industrial parks, and farmland concentrated in large-scale operation", which was established as the basic guiding principle of rural construction.In order to implement the "Three Concentrations" strategy, the central village planning formulation was started, and the village supporting facilities and public space were improved, forming a relatively concentrated "block" layout, which was in sharp contrast with the spatial texture of houses built by villagers spontaneously (Table 1).In the implementation of the central village planning, the surrounding cultivated land and ecological land need to be occupied, but the original scattered homesteads cannot be effectively reclaimed and Most of the central village planning failed to be implemented, and although some central villages were built, the actual occupancy rate of villagers was low due to the difficulty of supporting the configuration of service facilities.suchas primary schools due to their population size (Wang et al., 2001).

Planning and regulation of villagers
From the perspective of regulation effect, this stage mainly regulated the "single administrative areas" of rural construction space, while the regulation of agricultural space and ecological space was relatively weak.At the same time, the regulation at this stage was dominated by the planning department, and it lacks effective connection with the horizontal departments such as land, housing, water conservancy, environmental protection and forestry, so the overall effect of regulation was not satisfactory.

The "Comprehensive" regulation of three types of rural space 3.2.1 Regulation of all types of suburb unit planning (2012present)
In 2012, Shanghai determined the construction land strategy of "locking the total quantity and growing the intension", and the reduction of construction land became the main task of planning and regulation in rural areas in the new period (Zhuang et al., 2013).The suburb unit planning formulation was started then, which was positioned as the detailed planning of the coordination of the whole land and whole elements and coverage of space of the entire administrative area at the town level.By the end of 2019, 86 agriculture-related streets and towns in Shanghai have completed the formulation of suburb unit planning.
Taking Langxia suburb unit planning as an example (Fig. 1), the planning regulation content is divided into three parts.First is the integration and replacement of construction land and cultivated land, replacing and reclaiming idle and scattered construction land in rural areas outside the boundary of urban development into cultivated land, and at the same time, reducing the indicator of construction land by 1/3 for the construction of areas similar to concentrated building areas.Its internal logic is to promote the intensive use of land and the improvement of ecological environment in rural areas through the spatial transfer of construction land indicators; the second is to integrate the special planning of agriculture and ecology, and realize the differentiated regulation of agriculture and ecological space.Implement the boundaries of permanently protected farmland, subdivide the agricultural production and planting subareas and configure agricultural facility land; implement the ecological protection boundaries and optimize the subdivision of the general ecological space and land of agriculture, forestry and water; the third is to refine the guidance of village construction and define the regulation requirements of supporting facilities, housing construction and rural style and features.In terms of regulation measures, the suburb unit planning implements the important control lines in rural areas through border regulation and rule regulation, and realizes the subdivision of three types of rural spaces, and regulates indicators for the development of various types of land.

Structural regulation of village layout planning (2014-present)
Village layout planning is an exploration of structural regulation in rural areas.In 2014, nine suburbs of Shanghai started to formulate village layout planning one after another, focusing on definition of the classification principles and functional positioning of various villages, and simultaneously implementing the control of total size of various land use to guide the formulation of suburb unit planning.
Taking the village layout planning of Jiading District as an example (Fig. 2), the planning regulation content is divided into three parts.First is to link up the spatial layout of urban and rural areas, and strengthen the linking between rural areas and urban areas in terms of functional orientation and development scale; the second is to define the "structural" content such as the overall spatial layout of the countryside, divide the current villages into three types: protection, preservation, and abolishment and merger (subdivided into two forms: abolishment and merger to move to apartments, and translation and merger), and simultaneously implement the scale decomposition plan of rural construction land, permanently protected farmland and ecological protection land; third, regarding the regulation of rural supporting facilities and features, it proposes the configuration standards for public service facilities and municipal infrastructure at town level, administrative village level and natural village level, and proposes guidance requirements for rural style and features.In terms of regulation measures, the scale and spatial layout of construction land are defined through indicator regulation, border regulation and function regulation, and the regulation requirements of rural development classification, supporting facility standards and rural style and features are defined through directory regulation.

Key area regulation of village design (2017-present)
Village design is an exploration of the regulation of rural spatial order and landscape style.In 2017, the Nineteenth National Congress of the Communist Party of China proposed the strategy of rural revitalization, and defined the twenty-character policy of prosperous industry, habitable ecology, civilized rural style, effective governance and affluent life.In order to improve the quality of rural spatial environment and shape the characteristic spatial order, on the premise of implementing the rural land use control and indicator control in the suburb unit planning, Shanghai proposed that village design can be carried out as needed in the concentrated residential areas of villagers and key areas of villages.
Taking the design of Beixin Village in Jiading District as an example (Fig. 3), its regulation content is divided into three parts.First is to optimize the overall spatial pattern and landscape features of the village, strengthen the guidance of natural landscapes along the water and road, and propose design guidance such as planting in the courtyard space in front of and behind the house; the second is to formulate style and features design strategies for new construction, renovation and preservation of buildings, and to regulate the volume, style, material and color of buildings; third is to design important nodes and public spaces such as village entrance, waterfront lines, roads and bridges, public places, engineering facilities, waterfront, house surroundings and village entrance.Furthermore, the capital budget and time schedule of each construction project are completed synchronously.In terms of regulation measures, the village design achieves the regulation objectives through indicator regulation, border regulation and form regulation.The villagers' opinions are widely consulted in the formulation process, which shows greater flexibility in regulation methods.
From the perspective of regulation effect, the village layout planning has realized the overall control of rural functions, structure and scale, solved the "structural" problems of rural development, and provided superior guidance for the implementation of comprehensive regulation in suburb unit planning (WU, 2018); suburb unit planning has realized the comprehensive coverage of spatial regulation in rural areas, coordinated and implemented the land use needs of various rural projects, and solved the "implementation problems" of spatial regulation; village design actively integrated rural regional culture and characteristic elements, and effectively guided the construction of landscape style and features (Table 2).
From the perspective of regulation effect, the village layout planning has realized the overall control of rural functions, structure and scale, solved the "structural" problems of rural development, and provided superior guidance for the implementation of comprehensive regulation in suburb unit planning (Wu, 2018); suburb unit planning has realized the comprehensive coverage of spatial regulation in rural areas, coordinated and implemented the land use needs of various rural projects, and solved the "implementation problems" of spatial regulation; village design actively integrated rural regional culture and characteristic elements, and effectively guided the construction of landscape style and features (Table 2).

Reflection on problems of spatial regulation of rural areas in Shanghai
In 2018, Shanghai promulgated the Guidelines for Rural Planning, which confirmed the regulation framework of rural areas at three levels: village layout planning, suburb unit planning and village design, and made clear the linking with the planning formulation system within the urban development boundary (Fig. 4).However, whether this regulation system can be replicated and popularized needs more in-depth thinking.

Achieve full coverage of regulation objects, but the regulation of ecological space is weak
From the development of construction space regulation to space regulation of the entire administrative area, rural space regulation has gradually covered the entire administrative area (Fig. 5), and the encroachment of agriculture and ecological space has also been effectively alleviated.First, regarding the regulation of construction space, it has improved the land use control content covering increments and stocks on the basis of the original residential land regulation; secondly, regarding the regulation of agricultural space, it has realized the subdivision of land, delimited the boundaries of permanently protected farmland, realized the static boundary management, improved the zoning of planting and breeding subareas and configuration of agricultural facility land, and realized dynamic regulation of agricultural boundary through the balance indicators of cultivated land occupation and compensation; thirdly, regarding the regulation of ecological space, the boundaries of ecological protection has been implemented, and binding indicators such as forest coverage rate, river and lake water surface rate, land and water quality grade have been set to realize dynamic regulation of ecological and environmental carrying capacity.However, from the perspective of implementation effect, the regulation of rural construction space is specific and clear, and the regulation of various agricultural subdivision spaces is also effective, but the regulation of ecological space is only reflected in the delimitation of ecological protection boundaries, and the content is relatively limited.First of all, there is a lack of subdivision of spatial regulation units such as nature reserves, water source reserves and wetland reserves within the boundaries of ecological protection.Secondly, the subdivision of the three types of space is mainly based on the zoning method of agricultural land, construction land and unused land, and the general ecological space outside the boundaries of ecological protection lacks a clear scope definition, so it is difficult to implement the relevant regulation contents.Thirdly, although ecological space exists independently of construction space and agricultural space, there are also regulation requirements based on ecological objectives within construction space and agricultural space, such as the regulation requirements of ecological factors such as green space rate, fertilizer and pesticide usage (Yan & Zou, 2019).

The regulation measures are refined level by level, but the level of regulation refinement needs to be improved
Refined the regulation requirements according to the principle of "target indexation, index spatialization and spatial morphology", and the progressive, accurate and efficient regulation measures were formed.Firstly, the village layout planning coordinated the development orientation of villages and towns, decomposed the scale of construction land, and implemented various development goals as quantifiable indicators to achieve the integration of qualitative non-spatial content and quantitative spatial content; secondly, the suburb unit planning undertook the village layout requirements, and implemented various construction needs through border regulation, indicator regulation and function regulation measures, which are reflected in the subdivided land; thirdly, regarding village design, it adopted village design border regulation, form regulation and indicators regulation measures for key rural construction areas, and transformed the planar spatial regulation elements into three-dimensional form regulation criteria.Generally speaking, the regulation measures of "indicators + boundary + directory + rule + function + form" have been formed for the construction space, which has both the rigidity and flexibility of space regulation; the control measures of "boundary + indicator + rule" have been formed for agriculture and ecological space (Table 3).However, it should also be noted that the spatial regulation is too rigid and not flexible enough, and the refinement level of spatial regulation needs to be improved.The regulation of agriculture and ecological space is mainly reflected in the delimitation of rigid boundaries such as permanently protected farmland and ecological protection boundaries.A series of regulation indicators, such as forest coverage rate, river and lake water surface rate, land and water quality grade, are only the basic requirements for the protection of spatial carrying capacity.With the trend of modernization of agricultural functions and service of ecological functions, some new formats and projects, such as agricultural tourism, ecological sightseeing and nature education, need to be implemented in agricultural and ecological spaces.Access rules for these new projects should be formulated at the subdivision level, and related control requirements such as function, layout, intensity, form and style and features should be improved at the plot level.

Hierarchical division achieves effective linking, but there are many constraints on the content of town regulation
Rural areas in Shanghai are faced with resource and environmental constraints caused by a large number of inefficient idle rural construction land in the late stage of urbanization, and the reduction of rural construction land has become the focus of spatial regulation.In order to promote the reduction of construction land, the suburb unit planning has completed the subdivision of the comprehensive space land use at the town level and realized the bottom line control; in addition, the regulation of rural development content was completed in the form of plans, and the planning control indicators of various types of land (including floor area ratio, building density, green space ratio, building height, etc.) were defined.This method of integrating and formulating village planning at the village area level with land use regulation at the town area level is conducive to promoting the reduction of construction land, and is suitable for the fast-growing rural areas of Shanghai.However, in the vast central and western regions of China, the rural development is generally slow, and the actual demand for rural construction is small (Peng, et al., 2020).It is not particularly necessary to pursue the full coverage of rural development at the town level.
What is more needed at the village level is to strengthen guidance and reduce constraints.The determination of various development indicators should be the result of the deep participation of the market and villagers under the constraints of the bottom line (He, et al., 2017;Yang

Planning types
Regulation measures

Form regulation
Construction space , 2018;Zhao & Li, 2019).Therefore, when learning from the experience of Shanghai's rural space regulation, it is necessary to reduce the planning and regulation content of suburb unit planning at the town level, retain the content of its special planning coordination and land subdivision layout, and highlight its bottom line regulation role; however, the specific contents related to rural development, including regulation elements such as the development intensity and form control of various types of land, are put into the planning at the village level, and are refined and implemented through all-round consultation with villagers (Fan, 2015).
4 The regulation strategy of space of entire rural administrative area under the territorial spatial planning system

Refine regulation requirements of subareas
Agricultural space and ecological space are important carriers of rural economy.At present, passive protection mode is mostly adopted, which is mainly reflected in the delimitation of permanently protected farmland and ecological protection boundaries.However, due to the lack of rational utilization of multifunctional elements of agricultural space and ecological space, space resources are left unused, and the comprehensive benefits of agricultural space and ecological space are difficult to play.
It is necessary to further strengthen the subdivision of agricultural space and ecological space.Under the strictest farmland protection system, agricultural planting, breeding and other spaces should be regulated based on classification, and the needs of facilities agriculture, agricultural tourism and other formats should be taken into account, so as to realize the improvement from agricultural benefits to comprehensive benefits.Ecological space should be regulated differently according to ecological importance, and the access mechanism and land demand of ecological education, ecological sightseeing and services should be implemented on the basis of ensuring the integrity and systematicness of ecological service functions.

Subdivision of use units and plot polygon
Refine the objects of comprehensive spatial regulation level by level through "spatial zoning-usage unitplot polygon".First, based on the importance of space development, utilization and protection, the three lines that need strict regulation are extracted from the three types of rural spaces.The spaces beyond the three lines can be divided into flexible construction space, general agricultural space and general ecological space, forming the "three zones and three lines" in rural areas; secondly, according to the difference of leading functions of land, the three types of space in rural areas are further subdivided to form 14 types of use units; thirdly, according to the difference of land boundary and leading function, the 14 types of use units are subdivided into 23 plot polygon elements, the construction elements such as rural homestead, supporting facilities and road traffic are regulated, and the protection of ecological elements such as woodland, grassland, waters and marshes and tidal-flat area is strengthened (Fig. 6).

Clarify regulation levels and technical points 4.2.1 Regulation positioning at all levels
Determine the regulation positioning of "structural regulation-use regulation-factor regulation" according to the scope of administrative powers and spatial scale characteristics of county, township & town and village levels, and the principle of "hierarchical coverage and highlighting key points".Implement structural regulation at county area level, focusing on the control of the bottom line of spatial resources, completing the division of three types of spatial boundaries, and initially implementing quantitative indicators in spatial boundaries; implement use regulation at township & town area level.Through the overall planning of territorial space of towns, integrate the land needs of various special planning, realize the comprehensive space subdivision and use control, and implement various regulation needs in the use units; implement elements regulation at village area level.Through the village planning, implement the regulation elements in the plot polygon and transmit them to the detailed design of the village to directly guide the construction and implementation of the village.

Technical points at all levels
The focus of different levels of regulation is different, and their applicable planning techniques are also different (Fig. 7).At the county area level, it is necessary to define the rural functional structure, three types of spatial zoning and various scale decomposition.Combined with the functional positioning of villages, delimit the boundary between concentrated construction space and flexible construction space, and link departmental indicators, integrate township & town indicators, and decompose the scale of rural construction land.Define the agricultural industry orientation and main production tasks; delimit the boundary between permanently protected farmland and general agricultural space; decompose and implement the scale of cultivated land quantity and permanently protected farmland area in each village.Based on the importance and value of ecological resources, define ecological space functions, delimit ecological protection boundaries and general ecological space boundaries, decompose and implement the scale of ecological At the town level, the land use is defined, the use regulation unit is delimited, and the unit bearing indicator system is decomposed.Subdivide the construction land into homestead, industrial land, public service facilities land, etc., delimit the boundaries of construction use units such as village living areas and industrial areas, and specify the construction unit indicators such as the scale of various construction land, development intensity and villagers' building standards.Subdivide agricultural land into cultivated land, garden land, grassland, facility agricultural land and other agricultural land, delimit the boundaries of agricultural use units such as agricultural breeding, and specify the agricultural unit indicators such as the scale of various agricultural land and facility agricultural land.Subdivide the ecological land into woodland, grassland, water area, tidal-flat area and marshes and other ecological land, delimit the boundaries of ecological use units such as key ecological functional areas and ecological protection areas, and formulate corresponding access rules and list regulation.
At the village level, based on the wishes of villagers and market demand, delimit the boundaries of plot property rights polygon, and improve the control indicators of construction, agriculture and ecology.Delimit the property rights polygon of the construction plot, and superimpose the regulation elements such as the use, area, strength and form of plots; delimit the polygon of agricultural land property rights and strengthen the guidance of agricultural planting and breeding elements and spatial form elements; delimit ecological plot polygon, implement all protection and development elements into ecological polygon, specify the regulation indicators allowed for development, and improve the rules for the conversion of ecological land polygon.

Implement level-by-level transmission and classified superimposition
Construct a regulation element system where "basic elements are transmitted level by level and additional elements are classified and superimposed" (Fig. 8).The basic elements, which are applicable to the common regulation of the three types of spaces, are combined with the vertical government administrative powers to form a vertical transmission mechanism that is refined, decomposed and implemented level by level.Additional elements are suitable for characteristic regulation at different levels in three types of spaces, which is convenient to highlight key points and improve the efficiency of regulation.

Basic elements are transmitted level by level
Using six regulation tools of function regulation, rule regulation, border regulation, indicators regulation, directory regulation and form regulation, construct the basic element regulation system of "three types and six elements" (Fig. 8).Rule elements refer to elements that are difficult to locate in space, including function and use rules; spatial elements are the ones that guarantee the bottom line boundary, including control lines and indicators; supporting elements improve space regulation from two aspects of facilities and style and features.First, undertaking the quantity requirements of higher-level planning, the six regulation elements are implemented in the regulation zoning of the county area.Combined with the regulation points at the spatial level where it is located, they are gradually refined and decomposed into the use units of the town area, and finally transmitted to the element polygon of the village area.Control lines and indicators are the key to orderly connection and transmission between different levels.

Classified superimposition of additional elements
On the basis of basic elements, additional elements are classified and superimposed to meet the special regulation requirements of the three types of spaces at different levels.Taking rural tourism, eco-tourism and other projects of new industries and new business formats as examples, functional facilities such as catering, accommodation, parking and comprehensive services need to be laid out, which has the characteristics of small land use, flexible layout and being attached to the existence of three types of rural spaces.The regulation of basic elements adopts a top-down transmission approach.It is often difficult to accurately predict the scale and layout requirements of such facilities in the three types of spaces at the county area level.It is necessary to superimpose additional elements at the town and village area levels to facilitate the project implementation.
At the town area level, additional elements of three types of use units should be superimposed.For the construction unit, it is necessary to refine the villagers' building standards, including land and building area standards, retreating and spacing, construction control requirements, etc.For agricultural units, the boundary and scale of agricultural land for production and affiliated facilities should be implemented, such as drying machine room and pumping station; put forward the requirements of functional guidance and scale control for the point-shaped distributed facilities land needed for agricultural tourism; improve the regulation of farm produce quality certification rate, fertilizer and pesticide usage, comprehensive utilization rate of straws, soil pH and other additional agricultural unit indicators.For ecological units, it is necessary to implement the list and boundaries of ecological protection elements, such as nature reserves and water source protection areas, and formulate access rules and list management; the boundary, function, scale and other related control requirements should be made clear for the land used for ecological sightseeing service facilities.
At the village area level, additional elements of plot regulation should be superimposed.For construction plots, it is necessary to increase additional elements such as floor area ratio, building height limit, construction control and other plot form regulation.For agricultural plots, it is necessary to increase the requirements of planting and breeding types, scale and access project types, improve the construction control requirements of supporting agricultural tourism facilities, and define the compatible land boundary, detailed functions and related control requirements.For ecological plots, it is necessary to define the environmental capacity requirements; define the construction requirements of supporting ecological service facilities, including the type, scale, intensity, layout and corresponding control indicators allowed for development and construction; implement additional control elements such as vegetation coverage rate and original terrain soil retention rate.
At the same time, due to the differences in spatial scale and composition of regulation elements at different levels, a combination of rigid control and flexible guidance, dynamic maintenance of regulation means are needed.On the one hand, establish the rigid regulation requirements for the three control lines in rural areas, and define the mandatory contents the lowerlevel planning need to implement.On the other hand, for the space beyond the three control lines in rural areas, combine with the administrative powers of governments at all levels, reserve a part of flexible space, to realize total amount control and dynamic optimization.Through the above analysis of basic elements, additional elements and regulation means, suggestions on three types of rural spatial regulation measures are formed (Table 4).

Conclusion
Under the "five levels and three categories" system of territorial spatial planning, how to improve the comprehensive spatial regulation in rural areas is the starting point of this paper.The establishment of the comprehensive spatial regulation system in rural areas is a complex system involving political system, social economy and other fields, involving the key technical links of zoning and classification.The integration of its vertical hierarchical transmission mechanism and horizontal regulation elements is still a task that needs to be promoted in the future.

Fig. 1
Fig. 1 Suburb Unit Planning of Langxia.Source: Shanghai Urban Planning and Design Research Institute, Suburb Unit Planning of Langxia Town, Jinshan District [R], 2015

Fig. 4 Fig. 5
Fig. 4 Regulation System of Shanghai Territorial Spatial Planning.Source: The author sorted according to Shanghai Master Plan (2017-2035)

Fig. 6
Fig. 6 Three Types of Spatial Subdivision.self-drawing by the author

Fig. 8
Fig. 8 Transmission Diagram of Rural Space Regulation Elements.Source: self-drawing by the author In order to effectively guide villagers to build houses, in 1983, Shanghai promulgated the Detailed Rules for the Implementation of Land Management for Building Houses in Villages and Towns.It is stipulated that villagers can't occupy cultivated land for building houses, and can only coordinate and solve the problem in existing homesteads and open spaces, thus forming banded village settlements (Table

Table 2 "
Comprehensive" regulation of three types of rural space in Shanghai Source: self-drawing by the authorRegulation planning

and design types Regulation objects Regulation measures Regulation levels
Suburb unit planningThe entire administrative area of rural space (construction, agriculture, ecology)

Table 3
Three types of spatial regulation measures in rural areas of Shanghai Source: self-drawing by the author

Table 4
Suggestions on three types of rural spatial regulation measures • Rigid regulation, 〇 Flexible regulation, x No regulation involved Source: self-drawing by the author