Method, terminal and storage medium for converting land use type into plant function type

Abstract

The present application provides a method for converting land use types into plant functional types, including: S1, establishing a conversion matrix for converting land use types into plant functional types; S2, determining the standard of land use types and sorting the corresponding plant functional types; S3, limiting land use types, plant functional type grids and conversion coefficients; S4, determining penalty coefficients and objective functions; S5, finding the optimal solution through linear programming. The best solution of X(X*) can be calculated using the R language package "lpsolve". Therefore, in the initial state, the land use type can be better mapped to the plant functional type through X*, and the corresponding F value can be written as f(f∈[m,mn]), p=m means that all land use types are perfectly converted to plant functional types, and f=mn means that the expected results have been achieved, and the conversion of land use types into plant functional types has been completed quickly and accurately.

Description

Technical Field

[0001] The present application relates to the field of land treatment, and in particular to a method, terminal and storage medium for converting land use types into plant function types. Background Art

[0002] Land use type: refers to land resource units with the same land use mode. It is divided according to the regional differences in land use and is a basic regional unit that reflects the use, nature and distribution of land. It is a variety of land use categories with different use directions and characteristics formed by humans in the process of transforming and using land for production and construction. It reflects the economic characteristics of land and is manifested in land use modes with different characteristics. It is different from land type, which is a natural complex of various natural elements interacting in a region, reflecting the differences in the natural state characteristics of land. The delineation of land use types is not simply to understand the regional differences in the current use status, but more importantly to assess the productivity of land. Plant functional types (PFTs) are important advanced units of plant classification. Plant species divided according to life forms, plant communities with the same or similar life forms and similar biological and ecological characteristics, and consistent ecological relationships with water and heat conditions, are important bases for plant zoning. Introducing factors such as plant physiological and ecological processes, biophysical characteristics and phenological changes into models such as biogeographic models, biogeochemical models, land surface process models and global dynamic plant models helps to describe the dynamics of plants from a mechanistic perspective. Therefore, plant functional types are of great significance in analyzing ecosystem functions, evaluating the sensitivity of ecosystems to environmental changes, and predicting the response of plants to environmental changes. Different countries have different standards for the classification of land use types and vegetation functional types. Therefore, there are a variety of land use types and vegetation functional type data and products in the world, and land use types and vegetation functional types are not equal one by one, and there is no unified conversion method. The traditional conversion and classification format only requires a set of conversion matrices, which requires manual processing through retrieval tables, and the workload is large. This method does not require manual operation and human judgment at all, and is suitable for converting different vegetation functional type maps of various land use types. It relies entirely on computers for conversion, which greatly improves work efficiency and accuracy.

[0003] When predicting and simulating future scenarios, global climate models require vegetation function type maps as boundary condition inputs. However, future vegetation function type maps often need to be converted and generated through future land use change maps predicted by socio-economic models. The traditional conversion method is to develop a cross-query table and determine how much land use type to convert into how much vegetation function type by querying the table. However, this method has great limitations. First, the standards for land use type classification in various global products today are different, and the vegetation function types required by various global climate models are also different. This leads to the need to develop different cross-query tables for different combinations of products and models, which is a lot of work. Secondly, the classification of land use types is often vague. For example, "non-forest land" may correspond to grassland, farmland or city in humid areas, but in arid areas, it may correspond to grassland or desert. If only a fixed cross-query table is used for conversion, it will cause very large deviations. In order to overcome the above problems, this patent proposes a fast conversion method that is easy to operate and has strong applicability. Summary of the invention

[0004] The purpose of this application is to provide a method, terminal and storage medium for converting land use type into plant function type, so as to improve work efficiency and accuracy.

[0005] The embodiment of the present application is implemented as follows:

[0006] A method for converting land use types into plant functional types, comprising:

[0007] S1. Establish the conversion matrix of land use type to plant function type, namely X a = b; where X is the m*n matrix of unknown conversion coefficients, a is the m-length vector of land use types; b is the n-length vector of plant function types;

[0008] S2. Determine the standards for land use types and rank the corresponding plant functional types;

[0009] S3, limit the land use type, plant function type grid and conversion coefficient, that is: 0≤x ij ; a i , b j ≤1; And define: Among them, i represents the i-th land use type, j represents the j-th plant functional type;

[0010] S4, determine the penalty coefficient and the objective function, the penalty coefficient is: ranking index p ij (p∈2{1, 2, 3, ...m}) constitutes an m*n matrix P, and the objective function is: Get the solution of X when the F value is minimum;

[0011] S5. Find the optimal solution through linear programming, that is: I mn X≥z,I mn ≤0; where x is the value of the row {{x 11 , x 12 , …, x 1m}, {x 21 , x 22 , …, x 2m}, …, {x n1 , x n2 , …, x nm}}The vector obtained by expanding X; z is an mn-long vector of 0; o is an mn-long vector of 1; I mn is the mn-order identity matrix;

[0012] and Among them, a T is the transpose of a. i It means that it is an m-length vector whose elements are all zero except the i-th element 1.

[0013] Furthermore, determining the standard of land use type and sorting the corresponding plant function types includes: determining the sorting of plant function types from front to back according to the order of correlation between plants and land types from strong to weak.

[0014] The terminal comprises: a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor executes the program, the steps in the method of converting plant function types from land use types are implemented.

[0015] A computer-readable storage medium stores a computer program, which, when executed, implements the steps in the method for converting plant function types from land use types.

[0016] The method for converting land use types into plant functional types provided in the embodiment of the present application includes: S1, establishing a conversion matrix for converting land use types into plant functional types; S2, determining the standard of land use types and sorting the corresponding plant functional types; S3, limiting land use types, plant functional type grids and conversion coefficients; S4, determining penalty coefficients and objective functions; S5, finding the optimal solution through linear programming. The best solution for X(X*) can be calculated using the R language package "lpsolve". Therefore, in the initial state, the land use type can be better mapped to the plant functional type through X*, and the corresponding F value can be written as f(f∈[m,mn]), p=m means that all land use types are perfectly converted to plant functional types, and f=mn indicates that the expected results have been achieved, and the conversion of land use types into plant functional types has been completed quickly and accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A flowchart of a method for converting land use types into plant functional types provided in an embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0021] Example

[0022] like Figure 1 As shown, an embodiment of the present application provides a method for converting land use types into plant function types, the method comprising:

[0023] S1. Establish the conversion matrix of land use type to plant function type, namely X a =b; where X is the m*n matrix of unknown conversion coefficients, a is the m-length vector of land use types, and b is the n-length vector of plant function types.

[0024] Specifically, assuming that the projection data in the existing plant functional type map has m land use types and n plant functional types, for a specific grid cell of the land use type a and plant functional type b array, the conversion coefficient matrix needs to convert the land use type into the plant functional type. The conversion matrix of land use type to plant functional type can be:

[0025] a1x 11 +a2x 12 +···+a m x 1m =b1

[0026] a1x 21 +a2x 22 +···+a m x 2m =b2

[0027] …

[0028] a1x i1 +a2x i2 +···+a i x ij =b j

[0029] …

[0030] a1x m1 +a2x m2 +···+a m x nm =b n

[0031] Where i is the i-th (1, 2, 3...m) land use type, j is the j-th (1, 2, 3...n) plant functional type, x ij Represents the unknown conversion factor; a i is part of the i-th land use type raster, b j is part of the jth plant functional type raster.

[0032] The above matrix can be simply written as: Xa=b.

[0033] S2. Determine the standards for land use types and rank the corresponding plant functional types.

[0034] Specifically, if a grid cell is completely covered as "potential secondary forest land" in the land use type, but is detected as "no plant" in the plant functional type map, "no plant" will occupy all positions from "potential secondary forest land". Therefore, for each plant functional type, the land use type should be converted from the most likely to the least likely. Based on the correlation, we propose four types of land use types:

[0035] Take "wheat" as an example: 1) Highly correlated with land use type. "Annual C3 crops" ranks first in "wheat"; 2) The relationship with land use type is vague (unclear), "non-forestry secondary land" refers to a plant functional type coverage area, which ranks below "wheat"; 3) Weakly correlated with land use type but may be highly correlated with plant functional type, such as "annual C4 crops" in crops, which highly corresponds to the functional type of "corn". 4) Almost unrelated to land use type. For example, "urban land" and "primitive forest land" cannot be interpreted as crops. Therefore, they rank at the bottom of "wheat".

[0036] S3, limit the land use type, plant function type grid and conversion coefficient, that is: 0≤x ij ; a i , b j ≤1; And define: Among them, i represents the i-th land use type and j represents the j-th plant functional type.

[0037] S4, determine the penalty coefficient and the objective function, the penalty coefficient is: ranking index p ij (p∈2{1, 2, 3, ...m}) constitutes an m*n matrix P, and the objective function is: Get the solution of X when the F value is minimum.

[0038] S5. Find the optimal solution through linear programming, that is: I mn X ≥ z, I mn ≤0; where x is the value of the row {{x 11 , x 12 , …, x 1m}, {x 21 , x 22 , …, x 2m}, …, {x n1 , x n2 , …, x nm}}The vector obtained by expanding X; z is an mn-long vector of 0; o is an mn-long vector of 1; I mn is the mn-order identity matrix;

[0039] and Among them, a T is the transpose of a. i It means that it is an m-length vector whose elements are all zero except the i-th element 1.

[0040] Then, the optimal solution of X(X*) can be calculated using the R language package "lpsolve". Therefore, in the initial state, the land use type can be better mapped to the plant functional type through X*, and the corresponding F value can be written as f(f∈[m, mn]). p=m means that all land use types are perfectly converted to plant functional types, and f=mn indicates that the expected results are achieved. The present application also provides a terminal, including: a storage device and a processor, the storage device is electrically connected to the processor, the storage device stores a computer program that can be run on the processor, and when the processor executes the program, it implements the steps in the method of converting land use types into plant functional types to quickly and accurately convert land use types into plant functional types.

[0041] The present application also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed, the steps in the method for converting land use types into plant function types are implemented. By using a computer to read the readable storage medium, the computer can implement the operation of the method for converting land use types into plant function types, so as to quickly and accurately convert land use types into plant function types.

[0042] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for converting land use types into plant functional types, characterized in that: include: S1. Establish a conversion matrix for converting land use type to plant function type, that is, Xa=b; where X is an n*m matrix of unknown conversion coefficients, a is an m-length vector of land use type; b is an n-length vector of plant function type; S2. Determine the standard of land use type and sort the plant function types corresponding to the land use type; specifically, determine the sorting of plant function types from front to back according to the order of correlation between plants and land types from strong to weak; S3, limit the land use type, plant function type grid and conversion coefficient, that is: 0≤xj i ; a i , b j ≤1; And define: Where i represents the i-th land use type, j represents the j-th plant function type; x ji Represents the unknown conversion factor; a i is part of the i-th land use type raster, b j is part of the jth plant functional type raster; S4, determine the penalty coefficient and the objective function, the penalty coefficient P is: ranking index p ji Construct an n*m matrix P, where p ji ∈{1, 2, 3, ... m}, the objective function is: F(x) = sum Calculate the solution of X when the F value is minimum; p ji x ji is the product of each element in matrix P and the corresponding element in matrix X; where p ji Indicates the ranking value. The smaller the value, the higher the ranking and the greater the possibility of conversion. Based on the solution of X when the F(x) value is the minimum, the land use type conversion is performed, where the F(x) value is written as f, f∈[m, mn], f=m means that all land use types are perfectly converted to plant function types, and f=mn means that the expected result is achieved, and the land use type conversion to plant function type is completed; The calculation of the solution of X when the F value is the minimum includes: finding the optimal solution through linear programming, that is: I mn Y ≥ z, I mn Y≤o; where Y is the value of the row {{x 11 , x 12 , …, x 1m }, {x 21 , x 22 , …, x 2m }, …{x n1 , x n2 , …, x nm }}The vector obtained by expansion; z is a mn-long vector of 0; o is a mn-long vector of 1; I mn is the identity matrix of order mn; and Among them, a T is the transpose of a; q i It means that it is an m-length vector whose elements are all zero except the i-th element 1.

2. A terminal, characterized in that include: A memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor executes the program, the steps in the method for converting land use types into plant function types as described in claim 1 are implemented.

3. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the steps in the method for converting land use types into plant function types as described in claim 1 are implemented.

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