Nitrogen and phosphorus pollutant track tracing method and system

Abstract

The invention provides a nitrogen and phosphorus pollutant track tracing method and system, and the method comprises the steps: building an initialization vector line segment for a to-be-detected water body according to the geographic distribution of the water body through a GIS system, and carrying out the detection of the concentration of nitrogen and phosphorus pollutants at two ends; according to the nitrogen and phosphorus pollutant concentration detection data detected at the two ends, generating a traceability direction of the initialization vector line segment, according to the traceability direction, generating a vector line segment connected with the initialization vector line segment, and detecting the nitrogen and phosphorus pollutant concentration of a new end point of the vector line segment; comparing the nitrogen and phosphorus pollutant concentration of the new endpoint with the nitrogen and phosphorus pollutant concentration of the last endpoint to generate a new vector line segment; presetting a nitrogen and phosphorus pollutant concentration trigger threshold value and a back-test proportionality coefficient of the back-test vector line segment, and judging whether the back-test vector line segment is generated or not according to the nitrogen and phosphorus pollutant concentration of the new endpoint and the trigger threshold value; and carrying out nitrogen and phosphorus pollutant concentration detection on the new endpoint where the back-test vector line segment is located, so as to trace and locate the nitrogen and phosphorus pollutants.

Description

Technical Field

[0001] The present invention relates to the technical field of nitrogen and phosphorus pollutant treatment, and in particular to a nitrogen and phosphorus pollutant traceability method and system. Background Art

[0002] At present, the existing technology for tracing the source of nitrogen and phosphorus pollutants mainly uses chemical detection methods to detect the concentration of nitrogen and phosphorus substances in rivers or oceans, and determines the possible presence of nitrogen and phosphorus pollutants by visiting the upper reaches of rivers or around the coast of the ocean. However, the above existing technology requires a lot of human resources, and the tracing of nitrogen and phosphorus pollutants in rivers and oceans is not very accurate, resulting in poor tracing of nitrogen and phosphorus pollutants.

[0003] In addition, there are also major technical problems in the traditional chemical detection method for the concentration detection of nitrogen and phosphorus pollutants. Since nitrogen and phosphorus pollutants are important nutrients for microorganisms, they will become part of the microorganisms in the river due to the reproduction of microorganisms. Some microorganisms will be deposited in the surface soil of the river, and the nitrogen and phosphorus substances themselves will also be deposited in the soil, resulting in the actual detection of nitrogen and phosphorus pollutants in the water body itself. The concentration of nitrogen and phosphorus pollutants is low, making the accuracy of nitrogen and phosphorus pollutant tracing low. Summary of the invention

[0004] One of the inventive purposes of the present invention is to provide a method and system for tracing the trajectory of nitrogen and phosphorus pollutants. The method and system use GIS (geographic information management system) to construct vector line segments for pollutant tracing, wherein different vector line segments are connected end to end to determine the detection points of pollutants, and the possible directions of the pollutant sources are judged based on the vector line segments. In the present invention, the positions and straight-line distances of two adjacent detection points are determined using a predetermined vector line segment length, and the actual detected nitrogen and phosphorus concentrations of the two detection points are used as the tracing direction of the vector line segment, so that when the detection point meets the preset detection result, the endpoint of the corresponding vector line segment can be determined as the pollution source to be searched.

[0005] Another invention object of the present invention is to provide a method and system for tracing the trajectory of nitrogen and phosphorus pollutants, wherein the method and system utilize GIS (geographic information management system) and construct a backtest vector segment based on the vector segment, wherein the backtest vector segment is proportionally smaller than the vector segment, and the backtest vector segment and the vector segment extend in opposite directions, wherein the trigger generation condition of the backtest vector segment is realized according to the actual nitrogen and phosphorus concentration detection value of the endpoint of the vector segment. The vector segment can effectively reduce the number of detections, and can relatively effectively trace the source of nitrogen and phosphorus pollutants through the backtest vector segment detection method, thereby greatly improving the nitrogen and phosphorus pollution source location effect.

[0006] Another object of the present invention is to provide a method and system for tracing the trajectory of nitrogen and phosphorus pollutants. In the method and system, the backtest line segment can be triggered into multiple ones, so that the nitrogen and phosphorus pollutants can be detected and located multiple times within the trajectory range of the triggered backtest vector line segment, thereby making the accuracy of the nitrogen and phosphorus pollutant trajectory tracing more accurate and effectively reducing the detection frequency of the nitrogen and phosphorus pollutants as a whole.

[0007] Another object of the present invention is to provide a method and system for tracing the trajectory of nitrogen and phosphorus pollutants. The method and system also detect the nitrogen and phosphorus content of the surface soil per unit volume of the water body at the endpoints of the corresponding vector segment and the backtest vector segment, and use the nitrogen and phosphorus content of the surface soil per unit volume of the water body as a correction parameter to correct the nitrogen and phosphorus pollutant concentration of the water body itself, thereby effectively improving the accuracy of the tracing of the trajectory of nitrogen and phosphorus pollutants.

[0008] In order to achieve at least one of the above-mentioned invention objects, the present invention further provides a method for tracing the source of nitrogen and phosphorus pollutants, the method comprising: Constructing an initialization vector line segment for the water body to be detected according to the geographical distribution of the water body, and detecting the concentrations of nitrogen and phosphorus pollutants at both ends of the initialization vector line segment respectively; Generate the tracing direction of the initialization vector line segment according to the nitrogen and phosphorus pollutant concentration detection data detected at both ends of the initialization vector line segment, generate a vector line segment connected to the initialization vector line segment according to the tracing direction, detect the nitrogen and phosphorus pollutant concentration at the new end point of the vector line segment, and compare the nitrogen and phosphorus pollutant concentration at the new end point with the nitrogen and phosphorus pollutant concentration at the previous end point to generate a new vector line segment; Preset a nitrogen and phosphorus pollutant concentration trigger threshold and a backtesting ratio coefficient of the backtesting vector segment, and determine whether to generate a backtesting vector segment according to the nitrogen and phosphorus pollutant concentration at the new endpoint of the vector segment and the nitrogen and phosphorus pollutant concentration trigger threshold of the backtesting vector segment; A backtest vector segment having a length corresponding to the proportional coefficient of the previous vector segment is generated according to the backtest proportional coefficient, wherein the tracing direction of the backtest vector segment is opposite to the tracing direction of the previous vector segment, and the new endpoint of the backtest vector segment is subjected to nitrogen and phosphorus pollutant concentration detection for tracing and locating the nitrogen and phosphorus pollutants.

[0009] According to one of the preferred embodiments of the present invention, when the nitrogen and phosphorus pollutant concentration data at both ends of the initialization vector segment are obtained, the nitrogen and phosphorus pollutant concentrations at both ends of the initialization vector segment are determined, and one endpoint of the initialization vector segment with a larger nitrogen and phosphorus pollutant concentration is used as the endpoint of the next vector segment. The next vector segment in the extension direction of the water body is generated according to the generated water body distribution map, and the nitrogen and phosphorus pollutant concentration at the new endpoint of the next vector segment is calculated. The nitrogen and phosphorus pollutant concentration at the new endpoint of the next vector segment, the nitrogen and phosphorus pollutant concentration at the previous endpoint, and the nitrogen and phosphorus pollutant concentration trigger threshold of the backtest vector segment are compared respectively to determine whether to generate a backtest vector segment or a new vector segment.

[0010] According to another preferred embodiment of the present invention, the method for generating the backtest vector segment includes: if the new endpoint of the current vector segment is less than a preset nitrogen and phosphorus pollutant concentration trigger threshold of the backtest vector segment, the new endpoint of the current vector segment is used as an endpoint of the backtest vector segment, and the new endpoint of the backtest vector segment is generated in the direction opposite to the source extension of the current vector segment, wherein the new endpoint of the backtest vector segment is located on the current vector segment, and the new endpoint of the backtest vector segment does not coincide with the two endpoints of the current vector segment.

[0011] According to another preferred embodiment of the present invention, the method for generating the backtest vector segment includes: if the new endpoint of the current vector segment is smaller than the preset nitrogen and phosphorus pollutant concentration trigger threshold of the backtest vector segment, then calculating the length of the backtest vector segment according to the current vector segment length and the preset backtest proportional coefficient, wherein the length of the backtest vector segment is the product of the previous vector segment length and the preset backtest proportional coefficient.

[0012] According to another preferred embodiment of the present invention, the backtesting ratio coefficient of the backtesting vector segment is set to 1 / 2 n , wherein n in the backtest ratio coefficient represents the number of backtests of the corresponding vector segment, and different backtest vector segments are generated according to the backtest ratio coefficient and the number of backtests. The specific steps include: defining the nitrogen and phosphorus pollutant concentration of the new endpoint of the current vector segment to be less than the nitrogen and phosphorus pollutant concentration trigger threshold of the backtest vector segment, then the current is the first backtest, n=1, at this time the backtest ratio coefficient is 1 / 2, defining the backtest vector segment of the first backtest as the first backtest vector segment, and defining the length of the current vector segment as l, Then the length of the backtest vector segment of the first backtest is l 1 = l *1 / 2, from the new endpoint of the current vector segment to the current vector segment l 1The position is used as the new endpoint of the first backtest vector line segment, and the nitrogen and phosphorus pollutant concentration detection is performed at the new endpoint of the first backtest vector line segment.

[0013] According to another preferred embodiment of the present invention, after the nitrogen and phosphorus pollutant concentration data of the new endpoint of the first backtest vector line is obtained after the first backtest, if the nitrogen and phosphorus pollutant concentration data of the new endpoint of the first backtest vector line segment is less than the nitrogen and phosphorus pollutant concentration trigger threshold of the backtest vector line segment, a second backtest is performed, and at this time, the backtest ratio coefficient value of the second backtest is 1 / 2 2 =1 / 4, define the backtest vector line segment of the second backtest as the second backtest vector line segment, the second backtest vector line segment uses the new endpoint of the first backtest vector line segment as the connected endpoint, and uses the opposite direction of the current vector line segment tracing back to extend the direction as the second backtest vector line segment tracing back to extend the direction, the length of the second backtest vector line segment is l 2 = l *1 / 4, locate the new endpoint of the second backtest vector segment on the vector segment, and perform the nitrogen and phosphorus pollutant concentration detection at the new endpoint of the second backtest vector segment.

[0014] According to another preferred embodiment of the present invention, the nitrogen and phosphorus pollutant trajectory tracing method includes: presetting the backtest cutoff length l s or backtest cutoff times n s , when the length of the nth backtest vector segment of the nth backtest l n Less than the backtest cutoff length l s , or the nth backtest is greater than the backtest cutoff number n s , then the distance between the new endpoint located by the current nth backtest vector segment and the previous endpoint of the current vector segment is used as the range of pollutant trajectory tracing.

[0015] According to another preferred embodiment of the present invention, if the nitrogen and phosphorus pollutant concentration detected at the new endpoint of the current vector segment is lower than the nitrogen and phosphorus pollutant concentration at the previous endpoint, the new endpoint of the current vector segment in different tracing directions is regenerated based on the water body distribution of the previous endpoint of the current vector segment and the GIS system. If there are at least m directions in which the nitrogen and phosphorus pollutant concentrations of the new endpoint of the current vector segment are lower than the nitrogen and phosphorus pollutant concentrations of the previous endpoint of the current vector segment, the previous endpoint of the current vector segment is taken as the origin, and the nitrogen and phosphorus pollutant tracing is carried out in the water area of ​​the circular area with the current vector segment as the side length.

[0016] According to another preferred embodiment of the present invention, the method for calculating the concentration of nitrogen and phosphorus pollutants includes: obtaining the nitrogen and phosphorus pollutant concentration by measuring the unit volume of water body at the endpoint location water area of ​​the current vector segment or the backtest vector segment, and measuring the nitrogen and phosphorus pollutant content by measuring the underwater surface soil with the same unit volume of the endpoint location water area, and adding the nitrogen and phosphorus pollutant content measured by the same unit volume of underwater surface soil to the nitrogen and phosphorus pollutant concentration measured by the unit volume of water body as the corrected nitrogen and phosphorus pollutant concentration.

[0017] In order to achieve at least one of the above-mentioned invention purposes, the present invention further provides a nitrogen and phosphorus pollutant track tracing system, which executes the above-mentioned nitrogen and phosphorus pollutant track tracing method.

[0018] The present invention further provides a computer-readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the above-mentioned nitrogen and phosphorus pollutant traceability method. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Shown is a schematic flow chart of a method for tracing the source of nitrogen and phosphorus pollutants according to the present invention.

[0020] Figure 2 What is shown is a schematic diagram of the topological structure of the traceability detection in the present invention.

[0021] Figure 3 Shown is a schematic diagram of the backtest line segment structure of the traceability detection in the present invention. DETAILED DESCRIPTION

[0022] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0023] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0024] Combination Figure 1-Figure 3The present invention provides a method and system for tracing the trajectory of nitrogen and phosphorus pollutants. The method mainly includes the following steps: first, it is necessary to obtain the information of the water area to be detected in the GIS system (Geographic Information System), wherein the GIS system has water area information such as rivers, oceans, and lakes pre-made by remote sensing satellites and other methods, and the water area information includes map information such as the geographical location of the water area, the water flow of the water area, and the extension direction of the water area. The above map information is pre-made by the GIS system itself. The present invention only borrows the map information of the GIS system, and the method of generating the GIS system map is not repeated in this invention. Construct a vector segment according to the water body distribution map obtained by the GIS system. The present invention performs nitrogen and phosphorus pollutant concentration detection at the corresponding water area location based on the endpoints of the vector segment, and constructs a new vector segment or back-tests the vector segment based on the nitrogen and phosphorus pollutant concentration detection data of the different endpoints, wherein the vector segment is constructed by connecting the endpoints of the previous vector segment, and the back-tested vector segment is constructed based on the direction opposite to the tracing direction of the previous vector segment. The tracing direction of the vector line segment is obtained by the actual detected nitrogen and phosphorus pollutant concentration between the new short point of the current vector line segment and the previously connected endpoint. Therefore, the present invention can effectively track the pollution trajectory of the nitrogen and phosphorus pollutants in the water body, and effectively locate the nitrogen and phosphorus pollutants in the water body based on the backtest vector line segment. The backtest vector line segment can effectively reduce the number of detections of nitrogen and phosphorus pollutants at different locations in the water body, effectively improve the efficiency of tracing the trajectory of the nitrogen and phosphorus pollutants, and reduce the cost of manual detection of nitrogen and phosphorus pollutants.

[0025] Specifically, combined with reference Figure 2 and Figure 3 The present invention takes a river area with branches as an example to illustrate. Figure 2 Middle A 1 is an initialization vector segment, wherein the initialization vector segment A 1 Take O 1 As the origin, the extension direction of the river water area in the GIS system is the tracing direction. It should be noted that in the present invention, the upstream direction of the river is used as the tracing direction for the extension direction of the vector line segment. In other preferred embodiments of the present invention, the downstream direction of the river can be used as the tracing direction, and the relevant tracing rules can be adjusted to achieve the same technical effect as the present invention. The present invention will not be described in detail. The initialization vector line segment A 1 When constructing the next vector segment, it is necessary to pre-determine the two endpoints of the current initialization vector segment. 1 and O 2 The nitrogen and phosphorus pollutant concentration value at the location, such as the initialization vector segment A 1 The endpoint O 1The nitrogen and phosphorus pollutant concentration at the location is c 1 , and initialize the vector segment A 1 The endpoint O 2 The nitrogen and phosphorus pollutant concentration at the location is c 2 When the nitrogen and phosphorus pollutant concentration value c is determined 1 and c 2 When the nitrogen and phosphorus pollutant concentration value c 2 >c 1 When the initialization vector segment A 1 The endpoint O 2 The extension direction indicated is used as the source tracing direction of the nitrogen and phosphorus pollutants. Figure 2 A 2 It should be noted that the vector line segment in the present invention is set to a fixed length, for example, the vector line segment can be set to 500 meters, at which point the endpoint O 1 Position and endpoint 2 The distance between the positions is 500 meters. Therefore, the detection of the vector line segment in the present invention can effectively reduce the detection frequency along the pollution line, and only needs to detect the fixed position first and then perform backtesting to confirm.

[0026] Since a river may have different tributaries, the present invention needs to construct vector line segments B and C of different tributaries with the help of the geographical features of the river water area in the GIS system, such as Figure 2 As shown, there are two tributaries in the upper reaches of the river, so from the vector line segment A 2 Starting at the position, in the vector line segment A 2 The endpoints of the tracing extension direction generate two different vector line segments B 1 and C 1 Represents vector segments on different branches. Furthermore, the vector segments on different branches determine whether the area segment connected by the current vector segment needs further tracing or backtesting based on the nitrogen and phosphorus pollutant concentration values ​​actually detected at the two endpoints. Figure 2 Mid vector segment B 2 and B 3 , and the vector segment C 2 and C 3 They are all vector line segments for further tracing of nitrogen and phosphorus pollutants in corresponding river branches.

[0027] It is worth mentioning that one of the core technical points of the present invention is how to perform the backtesting task of nitrogen and phosphorus pollutant tracing. Since the endpoints of the vector segments of fixed length are used as the nitrogen and phosphorus pollutant concentration detection data in the technical solution of the present invention, the vector segments of fixed length usually need to be set at a longer distance in order to reduce the detection frequency. As a result, the possibility of the endpoints of the vector segments exceeding the corresponding nitrogen and phosphorus pollutant emission source is generated, so it is necessary to backtest the corresponding vector segments. Generally speaking, when the tracing endpoint of the vector segment exceeds the corresponding nitrogen and phosphorus pollutant emission source, the nitrogen and phosphorus pollutant concentration value actually detected by the tracing endpoint of the corresponding vector segment will produce a sudden change, such as a sudden sharp drop in concentration. Because from the detection point of view, the highest concentration of nitrogen and phosphorus pollutants is detected at the source position. With the dilution effect of upstream water, the farther the distance downstream of the nitrogen and phosphorus pollutant source is, the lower the detection result will be, but a certain nitrogen and phosphorus content will always be maintained. The concentration of nitrogen and phosphorus pollutants in the vector segments at the upstream position that is not polluted by the pollution source will be much lower than that at the pollution source or downstream position. Since it cannot be ruled out that there are new nitrogen and phosphorus pollution sources upstream, the present invention needs to set a certain nitrogen and phosphorus pollutant concentration trigger threshold for the backtest vector segment to detect whether there is a nitrogen and phosphorus pollution source within the position of the new endpoint of the corresponding vector segment. It should be noted that in the present invention, the nitrogen and phosphorus pollutant concentration trigger threshold of the backtest vector segment can be set according to the nitrogen and phosphorus pollutant concentration of the endpoint of the corresponding downstream vector segment. For example, one-third of the nitrogen and phosphorus pollutant concentration at the connection endpoint of the corresponding vector segment can be set as the nitrogen and phosphorus pollutant concentration trigger threshold of the backtest vector segment of the new endpoint of the corresponding vector segment.

[0028] For example, see Figure 3 The present invention discloses a schematic diagram of a structure for triggering the backtest vector segment. 1 The endpoint O 1 and O 2 The concentrations of nitrogen and phosphorus pollutants detected at the locations are c 1 and c 2 , if the nitrogen and phosphorus pollutant concentration trigger threshold of the backtest vector segment at the new endpoint of the vector segment is 0.3c 1 , when the c 2 <0.3c 1 , the first backtest task is triggered. Since the backtest ratio coefficient is defined as 1 / 2 in the system n , where n represents the number of backtest tasks. When performing the first backtest task, the backtest ratio coefficient is 1 / 2. Under the first backtest task, the backtest line segment is defined as the first backtest line segment, and the length of the corresponding first backtest vector line segment is the product of the connected vector line segment and the corresponding backtest ratio coefficient. Define the length of the vector line segment l, define the length of the first backtest vector segment as l 1 , the backtest ratio coefficient value is 1 / 2, then the length of the corresponding first backtest vector segment is l 1 = l* 1 / 2. The first backtest vector line segment is connected to the vector line segment A 1 The endpoint O 2 As the starting point, along the end point O 2 To endpoint O 1 Length up to l 1 The position at which 3 , position O 3 As the new endpoint of the first back-test vector line segment. Further, at the new endpoint of the first back-test vector line segment 3 The nitrogen and phosphorus pollutant concentrations are detected at the position to obtain the new endpoint O of the first backtest vector segment 3 The nitrogen and phosphorus pollutant concentration value c 3 , further determine the nitrogen and phosphorus pollutant concentration value c 3 Is it less than the nitrogen and phosphorus pollutant concentration trigger threshold of 0.3c of the backtest vector segment? 1 , if c 3 <0.3c 1 , then generate a second backtest task; the second backtest task is the new endpoint O of the first backtest vector segment 3 As the origin, along the endpoint O 2 To endpoint O 1 The backtest task endpoint is located in the direction. Since the system preset backtest ratio function is 1 / 2 n , when n=2, the corresponding backtest ratio coefficient is 1 / 4. Define the backtest vector line segment under the second backtest task as the second backtest vector line segment, and define the length of the second backtest vector line segment as l 2 , the length of the corresponding vector segment is l , the length of the second backtest vector segment l 2 = l *1 / 4. Figure 3 As shown, the new endpoint of the second backtest vector line segment is O 4 At this time, the new endpoint O of the second back-test vector segment 4 When the second back-test vector line segment new endpoint O 4 The nitrogen and phosphorus pollutant concentration on the surface is not less than the corresponding nitrogen and phosphorus pollutant concentration trigger threshold of 0.3c 1 , then locate the pollution source to the new endpoint O of the second backtest vector segment 4and the new endpoint O of the first backtest vector segment 3 between.

[0029] In one of the preferred embodiments of the present invention, it is necessary to set a backtest cutoff condition, wherein the present invention presets a backtest cutoff length l s or backtest cutoff times n s , when the length of the nth backtest vector segment of the nth backtest l n Less than the backtest cutoff length l s , or the nth backtest is greater than the backtest cutoff number n s , then the distance between the new endpoint located by the current nth backtest vector segment and the previous endpoint of the current vector segment is used as the range of pollutant trajectory tracing.

[0030] In order to expand the search direction of the vector segment and the current vector segment, the present invention performs the following processing on the nitrogen and phosphorus pollutant concentration detected at the endpoint of the current vector segment: if the nitrogen and phosphorus pollutant concentration detected at the new endpoint of the current vector segment is less than the nitrogen and phosphorus pollutant concentration at the previous endpoint, then based on the previous endpoint of the current vector segment and the water body distribution of the GIS system, new endpoints of the current vector segment with different tracing directions are regenerated; if there are at least m directions in which the nitrogen and phosphorus pollutant concentrations of the new endpoints of the current vector segment are less than the nitrogen and phosphorus pollutant concentrations of the previous endpoint of the current vector segment, then the previous endpoint of the current vector segment is taken as the origin, and the nitrogen and phosphorus pollutant tracing is performed in the water area of ​​a circular area with the current vector segment as the side length.

[0031] In one of the preferred embodiments of the present invention, the method for calculating the concentration of nitrogen and phosphorus pollutants includes: obtaining the nitrogen and phosphorus pollutant concentration by measuring the unit volume of water body at the endpoint location water area of ​​the current vector segment or the backtest vector segment, and measuring the nitrogen and phosphorus pollutant content by measuring the underwater surface soil with the same unit volume of the endpoint location water area, and adding the nitrogen and phosphorus pollutant content measured by the same unit volume of underwater surface soil to the nitrogen and phosphorus pollutant concentration measured by the unit volume of water body as the corrected nitrogen and phosphorus pollutant concentration.

[0032] The embodiments disclosed in the present invention, the process described above with reference to the flowchart can be implemented as a computer software program. The embodiments disclosed in the present invention include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program contains a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication part, and / or installed from a removable medium. When the computer program is executed by the central processing unit (CPU), the functions defined in the method of the present application are executed. It should be noted that the computer-readable medium described in the present application can be a computer-readable signal medium or a computer-readable storage medium or any combination of the two. The computer-readable storage medium can be, for example, but not limited to, a system, device or device of an electrical, magnetic, optical, electromagnetic, infrared segment, or semiconductor, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to, electrical connections with one or more wire segments, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In the present application, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, apparatus, or device. In the present application, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries a computer-readable program code. Such propagated data signals may be of various types, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless segments, wire segments, optical cables, RF, etc., or any suitable combination thereof.

[0033] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present invention. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0034] Those skilled in the art should understand that the embodiments of the present invention described and shown in the drawings are only examples and do not limit the present invention. The objectives of the present invention have been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments. Without departing from the principles, the implementation methods of the present invention may be deformed or modified in any way.

Claims

1. A method for tracing the source of nitrogen and phosphorus pollutants, characterized in that: The method comprises: Constructing an initialization vector line segment for the water body to be detected according to the geographical distribution of the water body, and detecting the concentrations of nitrogen and phosphorus pollutants at both ends of the initialization vector line segment respectively; Generate the tracing direction of the initialization vector line segment according to the nitrogen and phosphorus pollutant concentration detection data detected at both ends of the initialization vector line segment, generate a vector line segment connected to the initialization vector line segment according to the tracing direction, detect the nitrogen and phosphorus pollutant concentration at the new end point of the vector line segment, and compare the nitrogen and phosphorus pollutant concentration at the new end point with the nitrogen and phosphorus pollutant concentration at the previous end point to generate a new vector line segment; Preset a nitrogen and phosphorus pollutant concentration trigger threshold and a backtesting ratio coefficient of the backtesting vector segment, and determine whether to generate a backtesting vector segment according to the nitrogen and phosphorus pollutant concentration at the new endpoint of the vector segment and the nitrogen and phosphorus pollutant concentration trigger threshold of the backtesting vector segment; A backtest vector segment with a length corresponding to the proportional coefficient of the connected vector segment is generated according to the backtest proportional coefficient, wherein the tracing direction of the backtest vector segment is opposite to the tracing direction of the previous vector segment, and the new endpoint of the backtest vector segment is subjected to nitrogen and phosphorus pollutant concentration detection for tracing and locating the nitrogen and phosphorus pollutants.

2. A method for tracing the source of nitrogen and phosphorus pollutants according to claim 1, characterized in that: When the nitrogen and phosphorus pollutant concentration data at both ends of the initialization vector segment are obtained, the nitrogen and phosphorus pollutant concentrations at both ends of the initialization vector segment are determined, and one endpoint of the initialization vector segment with a larger nitrogen and phosphorus pollutant concentration is used as the endpoint of the next vector segment. The next vector segment in the extension direction of the water body is generated according to the water body distribution map, and the nitrogen and phosphorus pollutant concentration at the new endpoint of the next vector segment is calculated. The nitrogen and phosphorus pollutant concentration at the new endpoint of the next vector segment, the nitrogen and phosphorus pollutant concentration at the previous endpoint, and the nitrogen and phosphorus pollutant concentration trigger threshold of the backtest vector segment are compared respectively to determine whether to generate a backtest vector segment or a new vector segment.

3. A method for tracing the source of nitrogen and phosphorus pollutants according to claim 1, characterized in that: The method for generating the backtest vector segment includes: if the nitrogen and phosphorus pollutant concentration at the new endpoint of the current vector segment is less than a preset nitrogen and phosphorus pollutant concentration trigger threshold of the backtest vector segment, the new endpoint of the current vector segment is used as an endpoint of the backtest vector segment, and the new endpoint of the backtest vector segment is generated in the opposite direction of tracing back the current vector segment, wherein the new endpoint of the backtest vector segment is located on the current vector segment, and the new endpoint of the backtest vector segment does not coincide with the two endpoints of the current vector segment.

4. A method for tracing the source of nitrogen and phosphorus pollutants according to claim 1, characterized in that: The method for generating the backtest vector segment includes: if the new endpoint of the current vector segment is less than the preset nitrogen and phosphorus pollutant concentration trigger threshold of the backtest vector segment, then calculating the length of the backtest vector segment according to the current vector segment length and the preset backtest ratio coefficient, wherein the length of the backtest vector segment is the product of the previous vector segment length and the preset backtest ratio coefficient.

5. A method for tracing the source of nitrogen and phosphorus pollutants according to claim 1, characterized in that: Set the backtest scale factor of the backtest vector segment to 1 / 2 n , wherein n in the backtest ratio coefficient represents the number of backtests of the corresponding vector segment, and different backtest vector segments are generated according to the backtest ratio coefficient and the number of backtests. The specific steps include: defining the nitrogen and phosphorus pollutant concentration of the new endpoint of the current vector segment to be less than the nitrogen and phosphorus pollutant concentration trigger threshold of the backtest vector segment, then the current is the first backtest, n=1, at this time the backtest ratio coefficient is 1 / 2, defining the backtest vector segment of the first backtest as the first backtest vector segment, and defining the length of the current vector segment as l, Then the length of the backtest vector segment of the first backtest is l 1 = l *1 / 2, from the new endpoint of the current vector segment to the current vector segment l 1 The position is used as the new endpoint of the first backtest vector line segment, and the nitrogen and phosphorus pollutant concentration detection is performed at the new endpoint of the first backtest vector line segment.

6. A method for tracing the source of nitrogen and phosphorus pollutants according to claim 5, characterized in that: After the first backtest, the nitrogen and phosphorus pollutant concentration data of the new endpoint of the first backtest vector line is obtained. If the nitrogen and phosphorus pollutant concentration data of the new endpoint of the first backtest vector line segment is less than the nitrogen and phosphorus pollutant concentration trigger threshold of the backtest vector line segment, a second backtest is performed. At this time, the backtest ratio coefficient value of the second backtest is 1 / 2. 2 =1 / 4, define the backtest vector line segment of the second backtest as the second backtest vector line segment, the second backtest vector line segment uses the new endpoint of the first backtest vector line segment as the connected endpoint, and uses the opposite direction of the current vector line segment tracing back to extend the direction as the second backtest vector line segment tracing back to extend the direction, the length of the second backtest vector line segment is l 2 = l *1 / 4, locating the new endpoint of the second backtest vector line segment on the vector line segment, and performing the nitrogen and phosphorus pollutant concentration detection at the new endpoint of the second backtest vector line segment; The nitrogen and phosphorus pollutant trajectory tracing method includes: presetting the backtest cutoff length l s or backtest cutoff times n s , when the length of the nth backtest vector segment of the nth backtest l n Less than the backtest cutoff length l s , or the nth backtest is greater than the backtest cutoff number n s , then the distance between the new endpoint located by the current nth backtest vector segment and the previous endpoint of the current vector segment is used as the range of pollutant trajectory tracing.

7. A method for tracing the source of nitrogen and phosphorus pollutants according to claim 1, characterized in that: If the nitrogen and phosphorus pollutant concentration detected at the new endpoint of the current vector segment is lower than that at the previous endpoint, the new endpoint of the current vector segment in different tracing directions is regenerated based on the previous endpoint of the current vector segment and the water body distribution of the GIS system. If there are at least m directions in which the nitrogen and phosphorus pollutant concentrations of the new endpoint of the current vector segment are lower than those of the previous endpoint of the current vector segment, the previous endpoint of the current vector segment is taken as the origin, and the nitrogen and phosphorus pollutants are traced in the circular area waters with the current vector segment as the side length.

8. A method for tracing the source of nitrogen and phosphorus pollutants according to claim 1, characterized in that: The method for calculating the nitrogen and phosphorus pollutant concentration includes: obtaining the nitrogen and phosphorus pollutant concentration per unit volume of water body at the endpoint location water area of ​​the current vector line segment or the backtest vector line segment, and measuring the nitrogen and phosphorus pollutant content with the same unit volume of underwater surface soil in the endpoint location water area, and adding the nitrogen and phosphorus pollutant content measured by the same unit volume of underwater surface soil to the nitrogen and phosphorus pollutant concentration measured by the unit volume of water body as the corrected nitrogen and phosphorus pollutant concentration.

9. A nitrogen and phosphorus pollutant traceability system, characterized in that: The system implements a nitrogen and phosphorus pollutant traceability method as described in any one of claims 1-8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and the computer program is executed by a processor to implement a nitrogen and phosphorus pollutant traceability method as described in any one of claims 1-8.

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