CN103324984A - Method for judging urban minimum ecological land based on GIS - Google Patents

Abstract

The title of the invention is a method for determining the minimum ecological land use in cities based on GIS. The present invention relates to geographic information systems (GIS), landscape ecology and model construction, and mainly relates to a method for determining the minimum ecological land use in cities based on GIS. Provide method support for the technical problem of determining the minimum range of ecological land use in urban development. The key points of the technical solution to this problem are: 1. Combine the landscape ecological concept model with the evaluation method of ecosystem service function value, and with the support of GIS technology, construct 2. Using the scenario analysis method, set up four scenarios of retaining 30%, 40%, 50% and 60% of the urban area of ecological land, and analyze the rationality of the spatial distribution of the minimum ecological land ; 3. Extract the land with important ecosystem service function in the city from the constructed minimum ecological land use model. The invention provides a more feasible technical method for scientifically determining the minimum urban ecological land.

Description

A GIS-based Judgment Method of Urban Minimal Ecological Land

Technical field:

The invention relates to a geographic information system (GIS), landscape ecology and model construction, and mainly relates to a GIS-based method for judging urban minimum ecological land.

Background technique:

A city is a human-dominated economic and social complex ecological system, which is characterized by openness and relies on regional ecosystems outside its administrative boundaries to provide necessary ecological service functions. The food, raw materials, energy, resources and other substances and energy required for urban production and life need to be imported from the outside world through trade, and the waste generated by urban material and energy metabolism also depends on the absorption, decomposition and consumption functions of the external ecosystem. Even if a city does not retain any ecological land, it can still rely on the ecosystem service function of the external area to maintain itself. However, if it only relies on the ecosystem service function within the administrative boundary of the city, almost any city in the world will not be sustainable. exceeding its own ecological carrying capacity. Therefore, like urban carrying capacity, the minimum urban ecological land use is not an objective threshold calculated solely based on ecological theory, but a subjective index, which can only be determined by comprehensively balancing the needs and goals of the city's ecology, culture, and economy. That is, while meeting certain economic and social development goals, the important urban ecological land is protected to the greatest extent according to the importance of urban ecological land.

The importance of urban ecological land is not only related to its land use type, but also depends on its ecological vitality and landscape spatial structure characteristics. The importance of ecological land is firstly related to its land type. The importance of ecological land is also affected by the strength of its ecological vitality. The higher the vitality of the ecosystem, the stronger its carrying capacity, biodiversity and ability to resist disturbance. Among the various types of urban land use, the factor that has the greatest impact on ecological effects is green space, especially forest land. Landscape spatial structure is also a key factor affecting the importance of urban ecological land use. Both island ecology and landscape ecology have a large number of scientific observations to prove the significance of maintaining the continuity of nature and landscape patterns for the sustainability of the human ecological environment, and achieving a balanced state The number of species mainly depends on the size of the island and the distance from the island to the provenance, that is, the area effect and the distance effect.

It can be seen that the landscape spatial pattern analysis method of "combining concentration and decentralization" combined with the value estimation of ecosystem service functions, taking landscape components (land use type, ecological vitality), ecosystem service functions and landscape spatial structure as the basis The main evaluation factor, the establishment of a minimum ecological land use spatial analysis model based on urban development goals, is a good background support for the evaluation of ecological land use space.

On this basis, combined with the scenario analysis method to determine the minimum number, area and composition of urban ecological land, it is the basis for urban planning, urban planning (strategic) environmental impact assessment and other work.

Contents of the invention

The present invention will provide a GIS-based method for judging urban minimum ecological land.

The present invention realizes by following approach:

A GIS-based method for judging the minimum urban ecological land use is:

1. Data source selection. The selected data sources are mainly multi-temporal Landsat-5 satellite TM remote sensing images and high spatial resolution SPOT remote sensing images, supplemented by vector data and non-remote sensing data obtained from field surveys.

2. Analysis method of landscape spatial pattern. Based on the "combination of concentration and decentralization" landscape spatial pattern analysis method, combined with the value estimation of ecosystem service functions, landscape components (land use types, ecological vitality), ecosystem service functions and landscape spatial structure as the main evaluation factors, the establishment of The minimum spatial analysis model of ecological land based on urban development goals provides a good theoretical basis for the spatial evaluation of ecological land.

3. Model construction. The model construction is based on GIS and RS technology, according to the nature of the ecological landscape itself, some service functions of its spatial location (such as water conservation, soil erosion protection, etc.) and the relationship between the ecological landscape and other ecological landscapes Interpretation of information such as spatial location relationship, select representative index factors to form the index system of the model, and realize the quantitative expression of the urban minimum ecological land through superposition analysis and calculation of index data.

4. Selection of evaluation indicators. Guided by Richard T T Forman's landscape theory, and based on the principles of systematization and comprehensiveness of the index system, representativeness and independence of the index, and availability of data, the index evaluation system of the research has been established. Due to the complex types of evaluation indicators, it is difficult to compare their advantages and disadvantages with actual values. Therefore, the dimensions of each indicator are treated uniformly, expressed in numbers from 1 to 5. The greater the positive impact of the evaluation factor on the ecosystem, the greater its positive impact on the ecosystem. The larger the value is, the grading and assigning standard of each index is obtained by corresponding data research or AHP. The specific indicators are shown in Figure 1.

5. Scenario analysis. The comprehensive index of urban ecological landscape evaluation is used to reflect the protection level of ecological land. The index ranges from 0 to 5. The higher the index, the higher the protection level. The comprehensive evaluation results are sorted from high to low, taking 30%, 40%, 50% and 60% of the city's land area as the standard, and the corresponding ecological land range is extracted from the comprehensive evaluation results.

The advantages of the present invention are as follows:

1. The evaluation indicators selected by the present invention are representative and independent, and are relatively easy to obtain. The unified processing of the dimensions of each index is conducive to the comparison of the values of each evaluation index.

2. The data of the present invention are easier to obtain, and the remote sensing image has the characteristics of high resolution and high precision, which can ensure the calculation accuracy of the minimum ecological land range.

3. The calculation method of the minimum ecological land range suitable for urban development goals of the present invention is easy to operate, and the method has good operability and repeatability.

Description of drawings

Figure Schematic diagram of the construction of landscape ecological comprehensive evaluation index system

Detailed ways

Overview of the trial city: Shenzhen is located in the Pearl River Delta region with rapid economic development in southeast China. It borders Dongguan and Huizhou in the north, Hong Kong in the south, Daya Bay and Dapeng Bay in the east, and Lingdingyang at the mouth of the Pearl River in the west. Since the establishment of the special zone, Shenzhen's GDP has grown at an average annual rate of 27.8%, and its population has grown to nearly 10 million, completing the process that other cities have gone through for hundreds or even thousands of years. The rapid economic development of Shenzhen relies heavily on the development of land resources, and the contradiction between the demand for urban development land and the protection of ecological land has intensified. During the 15 years, the urban construction land increased from 6.7% to 35.63% of the total area, while the ecological land decreased sharply from 88.46% to 61.37%; (2) From the practical experience of international metropolises at home and abroad, Shenzhen is To achieve the urban development goal of "a modern international city", it is necessary to maintain an excellent urban ecological quality and provide a livable ecological environment. According to the principle of "getting greater benefits at a lower cost", timely protection of the minimum ecological land that plays an important role in maintaining the health of the urban and regional ecosystems, and control of the development speed of construction land are urgent problems to be solved in Shenzhen.

1. Data source selection. Remote sensing data sources include TM remote sensing images of Shenzhen in 1989, 1995, 2000 and 2003 and SPOT5 remote sensing images in 2003. Among them, the TM remote sensing data is mainly used for the dynamic analysis of the ecological environment in Shenzhen; the SPOT remote sensing data mainly takes advantage of its high spatial resolution and is fused with the Landsat-5 image in 2003 to extract information including the status of land use and river systems with high precision. , ocean coastline and wetland, road traffic, green space distribution and other special information. Both TM remote sensing images and SPOT remote sensing data adopt Shenzhen independent coordinate system. Among the collected non-remote sensing data, the vector data mainly includes the DEM data of Shenzhen City, the soil map of Shenzhen City and other data. DEM data is used for the extraction of thematic information such as slope, aspect, and soil erosion. Other non-remote sensing data include data obtained from field surveys and collected written data. Vegetation coverage and urban expansion survey data obtained from field surveys can be used to assist remote sensing interpretation and verify remote sensing interpretation results. The collection of written materials includes data such as statistical yearbooks and statistical bulletins officially promulgated by the government.

2. Analysis method of landscape spatial pattern. Based on the "combination of concentration and decentralization" landscape spatial pattern analysis method, combined with the value estimation of ecosystem service functions, landscape components (land use types, ecological vitality), ecosystem service functions and landscape spatial structure as the main evaluation factors, the establishment of The minimum spatial analysis model of ecological land based on urban development goals provides a good theoretical basis for the spatial evaluation of ecological land.

3. Model construction. The model construction is based on GIS and RS technology, according to the nature of the ecological landscape itself, some service functions of its spatial location (such as water conservation, soil erosion protection, etc.) and the relationship between the ecological landscape and other ecological landscapes Interpretation of information such as spatial location relationship, select representative index factors to form the index system of the model, and realize the quantitative expression of the urban minimum ecological land through superposition analysis and calculation of index data.

4. Selection of evaluation indicators. Guided by Richard T T Forman's landscape theory, and based on the principles of systematization and comprehensiveness of the index system, representativeness and independence of the index, and availability of data, the index evaluation system of the research has been established. Due to the complex types of evaluation indicators, it is difficult to compare their advantages and disadvantages with actual values. Therefore, the dimensions of each indicator are treated uniformly, expressed in numbers from 1 to 5. The greater the positive impact of the evaluation factor on the ecosystem, the greater its positive impact on the ecosystem. The larger the value is, the grading and assigning standard of each index is obtained by corresponding data research or AHP. The specific indicators are as attached.

According to the specific characteristics of Shenzhen, the method of obtaining the value of specific indicators is as follows: (1) Landscape components. Considering the particularity of the aquaculture water surface in Shenzhen, a strategy consistent with the green base landscape is adopted when assigning its area, and a score consistent with shrub land/garden is assigned to it when assigning land types. Taking the annual average NDVI value as an index to measure the ecological vitality of green vegetation, classify the NDVI in Shenzhen, and finally determine the classification standard based on the site survey in Shenzhen, as shown in Table 1. (2) Ecological service function. Using the Shenzhen DEM data, with the support of the GIS analysis software AVSWAT, the distance between the watershed unit and the water source, the sensitivity of water and soil loss, the vegetation status, and precipitation are used as factors to analyze the water conservation area level in Shenzhen. According to the division, the landscape patches in the first-level water conservation area, the second-level water conservation area, and the quasi-water conservation area are given evaluation scores of 5, 4, and 3, respectively, and the other areas are uniformly assigned a value of 1. Combined with the characteristics of Shenzhen's small regional scale and weak climate influence, the two factors of soil and slope were selected for spatial superposition analysis to evaluate the soil erosion protection function, and the analysis results were graded, so as to judge the sensitive protection of soil erosion in Shenzhen. The spatial distribution of functions. According to the survey on the distribution of endangered animals and plants in Shenzhen, 14 areas rich in biodiversity, such as Wutong Mountain and Qiniang Mountain, were selected as key areas for biodiversity conservation (see Table 2 for details). (3) Landscape space structure. The large-scale vegetation patches and seven medium-sized drinking water source reservoirs in the distribution area of rare and endangered species in Shenzhen were selected as the seed patches for the study. According to the seed patches selected above, three buffer zones with different distances of 3km, 4km and 5km were made respectively. The specific index assignment table is shown in Table 3.

Table 1 Grading and assignment of evaluation factors for landscape components in Shenzhen

Table 2 Grading and assignment of evaluation factors for ecological service functions in Shenzhen

Table 3 Distance Index Assignment Table

5. Carry out according to the comprehensive evaluation steps of urban ecological landscape. The first step is to generate corresponding thematic raster data according to the index items and index values of the third level in the evaluation index system and the evaluation scores of the corresponding grades. In the second step, according to the classification in the second level of the evaluation index system, the respective indicators are multiplied. The related superposition calculation method is shown in Table 5. The third step is to carry out weighted and superimposed calculations on the three indicators in the second level to obtain a comprehensive evaluation index. The formula is as follows: urban landscape synthesis = landscape pattern × W1 + landscape components × W2 + ecological service function × W3 where W1 = 0.3, W2=0.4, W3=0.3, which are the respective weight values of the three index factors, and the weight values are obtained by scoring by experts. The fourth step, in order to prevent the interference of non-ecological land types such as construction land and unused land, in the final result, assign the lowest score "0" to the area of this type of land. See Table 4 for the calculation method of the second-level independent index items.

Table 4 Calculation method of independent index items of the second level

6. Scenario analysis. The comprehensive index of ecological landscape evaluation in Shenzhen is used to reflect the protection level of ecological land. The distribution range of the index is 0-5. The higher the index, the higher the level of protection. The comprehensive evaluation results are sorted from high to low, taking 30%, 40%, 50% and 60% of the city's land area as the standard, and the corresponding ecological land range is extracted from the comprehensive evaluation results. The land use structure within the range of ecological land use in Shenzhen was extracted and the results were analyzed.

The results show that: based on the above scenario analysis and urban development goal constraint analysis, and following the principle of "getting greater benefits at a lower cost", the ecological land area that accounts for 50% of the urban area in the scenario analysis is determined to be the minimum ecological land in Shenzhen. The selected minimum ecological land not only conforms to the theoretical landscape optimization pattern and the protection of important ecological functions, but also meets the needs of Shenzhen's future urban development goals for the ecological environment; at the same time, it will not ignore economic and social development due to excessive attention to ecology.

Claims (1)

1. city minimum ecological land used decision method based on GIS is characterized in that:

1. landscape ecological conceptual model and Assessment Methods for Valuation of Ecosystem Service Function are combined, under the support of GIS and RS technology, made up city minimum ecological land used spatial analysis model, respectively according to 4 kinds of sights that keep urban size 30%, 40%, 50% and 60% ecological land, analyze the rationality of minimum ecological land used space distribution, the soil that has the important ecosystem service function in the middle of the city is extracted.

2. clear and definite city minimum ecological land used quantity, area and component, this is the basis of the work such as city planning, city planning (strategy) environmental impact assessment.