Suitability Evaluation of County-level Spatial Development under the

Support of Geographic National Conditions Information Jiongyu MA and Dongyu REN, China

ABSTRACT Suitability assessment for the spatial development is of fundamental importance in the national spatial planning, including protecting the national eco-space, rationally distributing the construction space, optimizing the spatial development pattern, etc. We establish the assessment index system, which is suitable for the spatial development of Pujiang County, by using geographical condition data, large-scale survey data, industrial special data, and industrial statistical data. During data processing, we use the GIS spatial analysis technique by choosing terrain, economic level, population density, and artery traffic as the suitability indexes, meanwhile choosing available land resources, available water resources, natural hazard, ecological vulnerability, and environmental capacity as the constraint indexes. From the aspect of the grid-based spatial scale, we particularly analyze the suitability of spatial development in Pujiang County, which involves four development levels: the most suitable, the more suitable, the less suitable, and the least suitable. Overall, each level of region occupies 4 %, 14 %, 15 %, and 67 %, respectively. The spatial suitability in Pujiang can be summarized as ‘large prohibitive development region and strong eco-system constraint’. Moreover, the suitability development level exhibits time-order character. The newly built is gradually outward according to current status. The development potential in this County tends to gradually reduce. In contrast to previous assessment mode with the administrative district as a unit, the spatial grid-based method makes a great breakthrough, which elaborately reflects the spatial difference between the development suitability and development constraint. This method offers technical supports for determining resource development intensity and improving the well-organized layout of the national spatial science.

Key words Land distribution, Land management, Land readjustment, Spatial planning

Suitability Evaluation of County-Level Spatial Development Under the Support of Geographic National Conditions Information (10741) Jiongyu Ma, Dongyu Ren and Xuehu Wen (China, PR)

FIG Working Week 2020 Smart surveyors for land and water management Amsterdam, the Netherlands, 10–14 May 2020 Suitability Evaluation of County-level Spatial Development under the

Support of Geographic National Conditions Information Jiongyu MA and Dongyu REN, China

1. INTRODUCTION Suitability assessment for the spatial development is the core content of county spatial planning, it is an effective method for solving disorderly expansion of construction land, and rationally distributing national spatial resource[1]. After the 19th National Congress of China, the spatial governance system and ability will become more scientific, systematic and democratic[2]. As an important theoretical and functional basis, the suitability assessment for the spatial development is guided by the concept of green development. In the overall development, the suitability assessment identifies regions with different development needs. Regions with low development costs, large capacity for resource environment and strong development needs to undertake high intensity socioeconomic activities, will be allowed to conduct high intensity development. On the other hand, regions with high ecological value but low development ability will be focused on eco-system maintenance rather than other socioeconomic activities[3-4]. In traditional suitability assessment methods for the spatial development, the evaluation unit is administrative district. But, using administrative district as the evaluation unit will lack the consideration of the actual spatial distribution. Thus, the evaluation result will hardly reflect the spatial development characteristics and details, and seriously affect the guidance value for reginal spatial functional zoning[5]. In recent years, under the support of GIS technology, spatial grids have been gradually applied to various types of research, providing ideas and technical supports[6-8]. The grid utilities equal size square grid to form the basic regional unit, providing different function and policy guidance for different unit and fully express the elemental differences in spatial distribution[9-12]. This paper uses GIS spatial technology and takes Pujiang , , China as the research area. Under the same evaluation index, the paper compares and analyzes the differences in the evaluation results of the suitability assessment for spatial development from the perspectives of the administrative district unit and the grid unit to determine a more suitable county range spatial development.

2. STUDY AREA Pujiang is a county that belong to the Chengdu city. Pujiang is in the southwest of Suitability Evaluation of County-Level Spatial Development Under the Support of Geographic National Conditions Information (10741) Jiongyu Ma, Dongyu Ren and Xuehu Wen (China, PR)

FIG Working Week 2020 Smart surveyors for land and water management Amsterdam, the Netherlands, 10–14 May 2020 Basin and Chengdu Plain, between 103 ° 19 ′ to 103 ° 41 ′ east longitude and 30 ° 05 ′ to 30 ° 20 ′ north latitude. Pujiang is adjacent to Pengshang city and Meishang city on the east side and is surrounded by mountain area on the west side. Pujiang is located at the intersection of Chengdu, and Ya'an, close to the Tianfu new district which is part of Chengdu's "half an hour Economic Circle". Currently, the main transportation method in Pujiang is by road. There are four main roads, eight county roads, and four coach stations (long distance bus stations). Furthermore, by 2020, the plan for "three railway, two highway and five expressway" will be realized in Pujiang. In 2016, the GDP of Pujiang is 11.797 billion Chinese Yuan (around $1.7 billion USD), a YoY growth of 10.5 percent. The per cap GDP of Pujiang is 46,463 Chinese Yuan (around $6,698.14 USD), a YoY growth of 16.2 percent. The structure of the three-sector (primary industry, secondary industry and tertiary industry) is 15.7:49.8:34.5. The year-end population of Pujiang in 2016 is 268,291 people, where 29.5 percent is urban population and 70.5 percent is rural population. The year-end permanent resident population is 254.1 thousand people, reaches an urbanization rate of 40.51 percent.

3. EVALUATION INDEXES AND RESEARCH METHODS 3.1 Evaluation indexes Suitability assessment for the spatial development applied the territorial function theory and the main function planning theory in assessing the spatial development. In addition, the suitability assessment for the spatial development consider important variables including ecological and environmental conditions, resource bearing and the degree of utilization, economic benefits and development needs of the area to provide more accurate assessment result. Thus, considering the territorial function and the main function planning of Pujiang, the evaluation indexes for the suitability assessment are generated from two aspects, suitability and constraint. The suitability indexes include topography, population, economic level, and impact of traffic arteries. The constraint indexes include available land resources, available water resources, impact of natural hazard and ecological vulnerability.

3.2 Research methods

3.2.1 Data collection and processing This research collects and uses data of Pujiang for the year 2016. The data sources include Development and Reform Bureau, Urban and Rural Planning Bureau, Environmental protection

Suitability Evaluation of County-Level Spatial Development Under the Support of Geographic National Conditions Information (10741) Jiongyu Ma, Dongyu Ren and Xuehu Wen (China, PR)

FIG Working Week 2020 Smart surveyors for land and water management Amsterdam, the Netherlands, 10–14 May 2020 Bureau, Land and Resources Bureau, Statistics Bureau, Transportation Bureau, and Water Authority. The data from Water Authority include gross product, nature preserve, permanent basic farmland, ecological red line, transport facilities layout, water resources (water resource include agricultural water consumption, industrial water consumption, domestic water consumption). The spatial data mainly includes the results of 2016 National Geographic Situation Monitoring and DEM with 10-meter resolution. In order to facilitate data analysis and calculation, the collected data is preprocessed. All text information is organized into table or text form. All spatial data coordinates are uniformly defined as the CGS2000 coordinate system, Gauss-Kruger projection, and all data are uniformly converted into GDB format for storage.

3.2.2 Multi-index comprehensive evaluation According to the evaluation index system, the entropy weight method[13] is used to determine the index weight. In information theory, information is a measure of the degree of order of a system, and entropy is a measure of the degree of disorder of a system; the smaller the information entropy of an indicator, the more information is provided by that indicator, which means it will have a heavier weight in the assessment. The Entropy weight method as following: 1、Standardize the data

Standardize the data of each indicator. Suppose there are k indicators 푋1, 푋2,…, 푋푘，where

푋푖 = {푋1, 푋2, … , 푋푛}, and after standardization the value of the indicators are 푌1, 푌2,…, 푌푘，

Then 푌푖푗 = (푥푖푗 − min(푥푖))/(max (푥푖) −min(푥푖))。 2、Calculate the Information Entropy for Each Indicator According to the definition of information, the information entropy of one set of data can

−1 푛 푛 be represented as 퐸푗 = −ln (푛) ∑푖=1 푃푖푗 ∗ 푙푛푃푖푗 where 푃푖푗 = 푌푖푗/ ∑푖=1 푌푖푗. If 푃푖푗 = 0, then

lim 푃푖푗 ∗ 푙푛푃푖푗 = 0. 푃푖푗→0 3. Calculate the weight of each indicator From the formula of Information Entropy, we can derive each indicator’s information

entropy 퐸1, 퐸2,…, 퐸푘 and use each indicator’s information entropy to calculate it’s weight by the following formula

1 − 퐸푖 푊푖 = （푖 = 1，2， … ，푘） 푘 − ∑ 퐸푖

Suitability Evaluation of County-Level Spatial Development Under the Support of Geographic National Conditions Information (10741) Jiongyu Ma, Dongyu Ren and Xuehu Wen (China, PR)

FIG Working Week 2020 Smart surveyors for land and water management Amsterdam, the Netherlands, 10–14 May 2020 Under the support of geographic information technology, construct a 10 meters by 10 meters spatial grid and extract the value of the eight factor: terrain, artery traffic, population density, economic level, available land resources, available water resources, impact of natural hazard, and ecological vulnerability from the grid. Then place them into the formula above and receive the weight of each factor as 0.03375、0.08960、0.22302、0.35005、0.06192、0.06306、 0.14089、0.03770. Then use the value from the spatial grid and the weight to calculate the weighted sum. The formula is as following: 푛

퐹표푣푒푟푙푎푦 푎푛푎푙푦푠푖푠 = ∑ 휆푖 · 푓푖 푖=0 where Overlay analysis is the multi-index comprehensive evaluation value, i is each indicator and fi is the assessment value of each indicator, λi is the weight for each indicator, and n is the number of indicators. When extracting the value for f, if the value for any of terrain, impact of natural hazard,

available land resources, available water resources, ecological vulnerability is zero then Foverlay

analysis will be zero which means this area is not suitable for development.

Using the formula above, the result for Foverlay analysis mostly range from 0 to 4 and scattered. Thus, the values of F in the interval [0,4] is split into four level, to form the hierarchical function

Goverlay grading.

level 1 3 ≤ 퐹overlay analysis level 2 2 ≤ 퐹overlay analysis < 3 퐺overlay analysis = level 3 1 ≤ 퐹overlay analysis < 2

{ level 4 0 ≤ 퐹overlay analysis < 1 The higher the level, the more potential that area has which means it is more suitable for development. The lower the level, the greater the barrier to development, and it is more inclined to protection than development.

3.2.3 Suitability assessment for spatial development under different perspective 1) Administrative District Perspective Pujiang currently has jurisdiction over one street, seven town and four townships. Based on the assessment result from administrative District, partition statistics from the GIS spatial analysis is applied. Partition statistics is to define the area in the layer according to the shape

Suitability Evaluation of County-Level Spatial Development Under the Support of Geographic National Conditions Information (10741) Jiongyu Ma, Dongyu Ren and Xuehu Wen (China, PR)

FIG Working Week 2020 Smart surveyors for land and water management Amsterdam, the Netherlands, 10–14 May 2020 and the value in the partition layer , and use this area as the range to count the raster values in the raster layer (the statistical methods include maximum, minimum and average values, etc.) and output a new raster statistics layer. 2) Spatial Grid Perspective Using a grid of unit 10 meters by 10 meters, Pujiang is divided into 5.8 million grids. Then analyze the statistical data and spatial data from the same administrative district using nuclear density analysis. Calculate the ratio of area of the Geographic National data to the area of the same type Geographic National data from the same administrative district, Then discretize the statistical data according to the above proportion.

4. COMPARATIVE ANALYSIS OF EVALUATION RESULTS 4.1 Evaluation Results The result of suitability assessment for spatial analysis is the base for divide urban, rural and ecological areas, thus, it is very important for the result to be scientific and accurate. According to the grading method in part 3.2, the assessment result is separated into four levels.

（a） Administrative District Perspective （b）Spatial Grid Perspective Figure1. The results of Suitability assessment for the spatial development Overall, the two assessment result shows that 4% of Pujiang’s space is level 1 (very suitable for development), 14% of the space is level 2(suitable for development), 15% of the space is level 3(less suitable for development) and 67% of the space is level 4( unsuitable for development). This shows that suitability of Pujiang’s land is mostly unable to be developed, the constraints on ecological environment is strong. The suitability level for development in Pujiang has strong temporal feature, and gradually develops around the existing built-up area and its development potential is gradually decreasing. The areas that are very suitable and suitable for development shows a stepwise distribution. These areas are distributed linearly

Suitability Evaluation of County-Level Spatial Development Under the Support of Geographic National Conditions Information (10741) Jiongyu Ma, Dongyu Ren and Xuehu Wen (China, PR)

FIG Working Week 2020 Smart surveyors for land and water management Amsterdam, the Netherlands, 10–14 May 2020 around Heshan street to Shouan County and in cluster distribution around Xilai town, Fuxing town, Datang town, which are concentrated and fast-developing areas. Chaoyang Lake and basic protected farmland areas are areas that unstable for developments and these areas have a dominant position in Pujiang development suitability, thus they should be protected and strictly controlled for development. Area that is Less suitable for development should be implemented with equal emphasis on proper development and protection.

4.2 Comparison of methods The study uses a point-to-point matching analysis to compare the evaluation result of the above evaluations using a spatial perspective and an administrative district perspective. The point-to-point matching analysis uses grid division technique to form unified grid covering the research area. Based on this, the cell of the grid is used to extract factors that are needed for analysis, then each cell is compared according to conditions that is given, if the cell satisfy the conditions then it is given a true value, otherwise it is given a false value. Finally, calculate the number of cells that is true and return the percentage of cells that satisfy the given conditions. The point-to-point matching analysis achieves a double comparison for spade and property of different factors, the higher the point-to-point matching value, the higher the consistency of space and property of the participant factor. In the process of selecting the suitability assessment result, if the development suitability level is the same for both the spatial grid perspective and administrative district perspective, then it is true. Under this condition, development suitability level of the two perspective is compared (table 1) and the schematic diagram of spatial distribution is given. (figure 2). From the two perspectives, the consistent and inconsistent area for development suitability level from the point-to-point analysis are further summarized to conclude the characteristics of the two method. Table 1. point-to-point matching analysis to compare the evaluation result(area:ha) Spatial Grid Administrative District point to point level Spatial distribution Perspective Perspective comparison（%） level 4 45395.96 35998.59 2.62 Figure 2，a level 3 6543.98 5708.68 1.64 Figure 2，b level 2 4385.86 8040.73 1.5 Figure 2，c level 1 1688.2 8266 61.93 Figure 2，d

Suitability Evaluation of County-Level Spatial Development Under the Support of Geographic National Conditions Information (10741) Jiongyu Ma, Dongyu Ren and Xuehu Wen (China, PR)

FIG Working Week 2020 Smart surveyors for land and water management Amsterdam, the Netherlands, 10–14 May 2020

（a）Comparison results of level 4 （b）Comparison results of level 3

（c）Comparison results of level 2 （d）Comparison results of level 1 Figure 2 Suitability assessment for spatial development under two perspective Under administrative district perspective, there are significant difference between areas with different development suitability level, but streets, townships are homogeneous. More specifically, area of each development suitability level has agglomeration trends according to administrative areas and their agglomeration trend are closely related to the results of multiple indicator. For example, the most suitable for development area are all located around Heshan street and Shoushan town, these two areas are level 1 from the comprehension result of multiple indicators. Chengjiang town, Chaoyang Lake town, Ganxi town, Datang town and Xilai town have concentratedly distributed 77% of the suitable for development area, these five areas are classified as level 2. Fuxing township, Daxing town, Baiyun township, and Guangming township have concentratedly distributed 69% of the less suitable for development area, so these four areas are level 3. Under the spatial perspective, each development suitability level bypass the administrative district, streets, townships, town are heterogeneous. On one hand, the classification of different

Suitability Evaluation of County-Level Spatial Development Under the Support of Geographic National Conditions Information (10741) Jiongyu Ma, Dongyu Ren and Xuehu Wen (China, PR)

FIG Working Week 2020 Smart surveyors for land and water management Amsterdam, the Netherlands, 10–14 May 2020 suitability level is not affected by the administration district, so it is more accurate locally. For example, towns around Lingxi river valley has higher level under spatial perspective, which is more accurate to its actual situation. On the other hand, according to the classification level of most suitable, suitable, less suitable, unsuitable, it can form a judgment for development timing across administrative district and this development timing often presents a “central-peripheral” structure, which is convenient for step to step guidance for spatial development. For example, the different suitable level around Heshan street and Shouan twonships shows the chronical order of the spatial development to uniform Heshan street and Shouan township, and critical problem during the development can be easily solved with the result of signal indictor. From above, area that is classified as development suitability of level 3 and level 4 is 89.53% of the total area of Pujiang for spatial perspective and 71.89% for administrative district perspective. This fully reflected Pujiang’s prohibited development area is lager and ecological environment constraint is strong, which is also correspondent to Pujiang’s current goal of “Green Paradigm”. Comparing the two perspective, spatial perspective breaks the restrict on administrative district and can better support the optimization fo spatial layout, arrange the timing of spatial development and formulate different control policies.

CONCLUSIONS We establish the assessment index system, which is suitable for the spatial development of Pujiang County, by using geographical condition data, large-scale survey data, industrial special data, and industrial statistical data. During data analysis, we use perspectives of the administrative district unit and the grid unit to assessment the suitability of terrain, economic level, population density, artery traffic, available land resources, available water resources, natural hazard, ecological vulnerability of Pujiang. overall, the spatial grid-based method makes a great breakthrough, which breaks the restrictions of the administrative region and elaborately reflects the spatial difference between the development suitability and development constraint. This method offers technical supports for determining resource development intensity and improving the well-organized layout of the national spatial science. At the same time, the grid is used as the smallest unit, which can be better combined with the results of land planning and urban planning, and the analysis results have prominent temporal characteristics, which can better support the optimization of spatial layout and formulate differentiated management and control policies.

Suitability Evaluation of County-Level Spatial Development Under the Support of Geographic National Conditions Information (10741) Jiongyu Ma, Dongyu Ren and Xuehu Wen (China, PR)

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Suitability Evaluation of County-Level Spatial Development Under the Support of Geographic National Conditions Information (10741) Jiongyu Ma, Dongyu Ren and Xuehu Wen (China, PR)

FIG Working Week 2020 Smart surveyors for land and water management Amsterdam, the Netherlands, 10–14 May 2020 CONTACTS Title Given name and family name：Jiongyu Ma Institution：The Third Geoformation Mapping Institute of Minist of Natural Resource Address：No.2, Jianshe Road, Longquanyi District, Chengdu City, Sichuan Province City：Chengdu COUNTRY：China Tel. +8613648044049 Email:[email protected]

Suitability Evaluation of County-Level Spatial Development Under the Support of Geographic National Conditions Information (10741) Jiongyu Ma, Dongyu Ren and Xuehu Wen (China, PR)

FIG Working Week 2020 Smart surveyors for land and water management Amsterdam, the Netherlands, 10–14 May 2020