Method for monitoring heavy metal pollution range of downstream of mine based on GIS (Geographic Information System) assistance

Abstract

The invention relates to the technical field of spectral analysis, in particular to a mine downstream heavy metal pollution range monitoring method based on GIS (Geographic Information System) assistance, which comprises the following steps of: firstly, correcting the initial concentration by virtue of the concentration of heavy metal substances in the neighborhood range of each monitoring point by considering that partial spectral data has errors due to shielding; determining an attenuation factor corresponding to each monitoring point by combining the corrected reference concentration distribution with a reference concentration attenuation area of each heavy metal substance in a neighborhood direction; furthermore, comprehensive analysis is carried out according to the attenuation factor of each monitoring point and the reference concentration of the heavy metal substances at each position, so that the final concentration of each heavy metal substance from each sewage draining exit in each monitoring point is determined more accurately; the pollution influence range, defined according to the final concentration, of each sewage draining exit is more accurate, and the corresponding heavy metal pollution range monitoring effect is better.

Description

Technical Field

[0001] The present invention relates to the technical field of spectral analysis, and in particular to a method for monitoring the heavy metal pollution range downstream of a mine based on GIS assistance. Background Art

[0002] The impact of mining activities on the environment is a global issue, especially heavy metal pollution. Heavy metal pollution not only affects the ecological environment, but also threatens human health. In order to effectively manage and remediate polluted areas, it is necessary to accurately monitor and assess the scope of heavy metal pollution. As a powerful spatial analysis tool, Geographic Information System (GIS) technology can provide detailed geographic location information to more accurately determine the specific scope of pollution, thereby indirectly improving the accuracy of heavy metal pollution monitoring.

[0003] Considering that the spectral information corresponding to heavy metals can be monitored through spectral data, the existing technology usually combines GIS technology with hyperspectral remote sensing technology that can reflect the heavy metal content to monitor the range of heavy metal pollution downstream of mines. That is, the range corresponding to the area where the heavy metal content monitored by hyperspectral remote sensing technology is greater than the pollution threshold or contains heavy metals is taken as the pollution range.

[0004] However, mining activities usually have multiple sewage outlets. The existing heavy metal pollution range monitoring method can only determine the observed comprehensive pollution area, but cannot clearly define the independent pollution range of each sewage outlet, which makes it difficult to formulate targeted pollution control measures, affecting the effect and efficiency of pollution prevention and control. That is, the existing method of monitoring the heavy metal pollution range downstream of mines based on GIS technology combined with hyperspectral remote sensing technology cannot effectively determine the independent pollution range of each sewage outlet, resulting in poor monitoring of the heavy metal pollution range. Summary of the invention

[0005] The present application provides a method for monitoring the range of heavy metal pollution downstream of a mine based on GIS assistance. The method first takes into account that occlusion may cause errors in some spectral data, so the initial concentration is corrected with the help of the concentration of heavy metal substances in the neighborhood range of each monitoring point, and then the attenuation factor corresponding to each monitoring point is determined through the corrected reference concentration distribution combined with the reference concentration attenuation area of ​​each heavy metal substance in the neighborhood direction; further, a comprehensive analysis is performed based on the attenuation factor of each monitoring point combined with the reference concentration of heavy metal substances at each position, so as to more accurately determine the final concentration of each heavy metal substance from each sewage outlet in each monitoring point, solving the problem that the existing method for monitoring the range of heavy metal pollution downstream of a mine based on GIS technology combined with hyperspectral remote sensing technology cannot effectively determine the independent pollution range of each sewage outlet, so that the pollution influence range of each sewage outlet defined according to the final concentration is more accurate, and the corresponding heavy metal pollution range monitoring effect is better.

[0006] The first aspect of the present application provides a GIS-assisted method for monitoring the scope of heavy metal pollution downstream of a mine, comprising:

[0007] Determine the initial concentration of each heavy metal substance corresponding to each monitoring point in the monitoring area based on the hyperspectral remote sensing data in the monitoring area centered on the mine sewage outlet;

[0008] The initial concentration is corrected according to the relative deviation of the initial concentration of various heavy metal substances in the neighborhood of each monitoring point, and the reference concentration of each heavy metal substance corresponding to each monitoring point is determined;

[0009] According to the distribution of the reference concentration, determining an attenuation factor characterizing the attenuation trend of the reference concentration of each heavy metal substance at each monitoring point in each neighborhood direction;

[0010] Determine the final concentration of each heavy metal substance from each sewage outlet at each monitoring point according to the attenuation factor on the pollution transfer path from each sewage outlet to each monitoring point in combination with the reference concentration;

[0011] The pollution impact range of each sewage outlet is determined according to the final concentration.

[0012] In an embodiment of the first aspect of the present application, the method for obtaining the reference concentration includes:

[0013] The other monitoring points within the preset neighborhood of each monitoring point are taken as the neighborhood points of each monitoring point; the initial concentration difference between each monitoring point and each corresponding neighborhood point under each heavy metal substance is calculated; the normalized value of the accumulated value of the initial concentration difference between each monitoring point and all neighborhood points under all heavy metal substances is taken as the occlusion probability of each monitoring point; the monitoring point whose corresponding occlusion probability is greater than the preset occlusion threshold is taken as the occlusion point;

[0014] The concentration of each heavy metal substance corresponding to the blocked point is interpolated according to the initial concentration of each neighborhood point corresponding to each blocked point through the Kriging interpolation method to obtain the reference concentration of each heavy metal substance at each blocked point; the initial concentration of each heavy metal substance at other monitoring points outside the blocked point is used as the corresponding reference concentration.

[0015] In an embodiment of the first aspect of the present application, the method for obtaining the attenuation factor includes:

[0016] Each neighborhood direction is taken as the target direction in turn, and each monitoring point is taken as the target point in turn; the next monitoring point of the target point in the target direction is taken as the corresponding first direction point; the previous monitoring point of the target point in the target direction is taken as the corresponding second direction point;

[0017] Under each heavy metal substance, when the reference concentration of the target point is greater than the reference concentration of the corresponding first direction point, the attenuation factor of each heavy metal substance at the target point in the target direction is obtained according to the change of the reference concentration of the target point relative to the first direction point and the second direction point;

[0018] Under each heavy metal substance, when the reference concentration of the target point is less than or equal to the reference concentration of the corresponding first direction point, the preset attenuation coefficient is used as the attenuation factor of each heavy metal substance of the target point in the target direction.

[0019] In an embodiment of the first aspect of the present application, the method for obtaining the attenuation factor of each heavy metal substance at the target point in the target direction according to the reference concentration change of the target point relative to the first direction point and the second direction point includes:

[0020] For each heavy metal substance, the ratio between the reference concentration of the target point and the corresponding reference concentration of the first direction point is taken as the first concentration ratio; the ratio between the reference concentration of the corresponding second direction point and the reference concentration of the target point is taken as the second concentration ratio; the positive correlation mapping value of the mean between the first concentration ratio and the second concentration ratio is taken as the corresponding attenuation factor.

[0021] In an embodiment of the first aspect of the present application, the method for obtaining the pollution transmission path includes:

[0022] The pollution transfer path from each sewage outlet to each monitoring point is planned using the Floyd algorithm.

[0023] In an embodiment of the first aspect of the present application, the method for obtaining the final concentration includes:

[0024] Under each heavy metal substance, the negative correlation mapping values ​​of the attenuation factors of all monitoring points in the pollution transmission path in the extension direction of the path are cumulatively multiplied and fused to determine the cumulative attenuation coefficient from each sewage outlet to each monitoring point under each heavy metal substance;

[0025] The target concentration of each heavy metal substance discharged from each sewage outlet is weighted by the cumulative attenuation coefficient to determine the final concentration of each heavy metal substance from each sewage outlet at each monitoring point.

[0026] In an embodiment of the first aspect of the present application, the method for obtaining the target concentration includes:

[0027] Under each heavy metal substance, the monitoring point where the normalized value of the reference concentration is greater than the preset exceeding standard threshold is taken as the concentration exceeding standard point corresponding to each heavy metal substance;

[0028] Under each heavy metal substance, the objective function model under each heavy metal substance is constructed based on the least square method according to the cumulative attenuation coefficient from all sewage outlets to each concentration exceeding the standard point combined with the reference concentration of the corresponding concentration exceeding the standard point;

[0029] The objective function is solved by the gradient descent method to determine the target concentration of each heavy metal substance discharged from each sewage outlet under the optimal solution.

[0030] In an embodiment of the first aspect of the present application, the objective function model includes:

[0031]

[0032] Among them, L k represents the objective function value under the kth heavy metal substance; N is the number of points where the concentration exceeds the standard; C k，i is the reference concentration of the kth heavy metal substance at the i-th concentration exceeding standard point; n is the number of sewage outlets; ρ′ k，y，i is the cumulative attenuation coefficient from the yth sewage outlet to the ith concentration exceeding standard point under the kth heavy metal substance; P k，y is the target concentration of the kth heavy metal substance discharged from the yth sewage outlet.

[0033] In an embodiment of the first aspect of the present application, the method for obtaining the pollution impact range includes:

[0034] For each heavy metal substance, the monitoring point from each sewage outlet where the final concentration is greater than the preset pollution threshold is used as the pollution monitoring point of each sewage outlet; the area formed by all the pollution monitoring points corresponding to each sewage outlet is used as the pollution impact range of each heavy metal substance discharged from each sewage outlet.

[0035] In an embodiment of the first aspect of the present application, the preset attenuation coefficient is set to 0.

[0036] In a second aspect, the present application provides a GIS-assisted system for monitoring the scope of heavy metal pollution in the downstream of a mine, the system comprising:

[0037] A data acquisition module, for determining the initial concentration of each heavy metal substance corresponding to each monitoring point in the monitoring area based on the hyperspectral remote sensing data in the monitoring area centered on the mine sewage outlet;

[0038] A concentration correction module is used to correct the initial concentration according to the relative deviation of the initial concentration of various heavy metal substances in the neighborhood of each monitoring point, and determine the reference concentration of each heavy metal substance corresponding to each monitoring point;

[0039] A first determination module is used to determine, according to the distribution of the reference concentration, an attenuation factor characterizing the attenuation trend of the reference concentration of each heavy metal substance at each monitoring point in each neighborhood direction;

[0040] A second determination module is used to determine the final concentration of each heavy metal substance from each sewage outlet at each monitoring point according to the attenuation factor on the pollution transfer path from each sewage outlet to each monitoring point in combination with the reference concentration;

[0041] The pollution impact range monitoring module is used to determine the pollution impact range of each heavy metal substance discharged from each sewage outlet according to the final concentration.

[0042] In a third aspect, the present application provides a computer device, comprising a memory and a processor. The memory is used to store computer program code, and the processor is used to call and run the computer program code from the memory to execute the method of the first aspect or any embodiment of the first aspect of the present application.

[0043] In a fourth aspect, the present application provides a computer program product, comprising a computer program code, which, when executed, performs the method of the first aspect of the present application or any embodiment of the first aspect.

[0044] In a fifth aspect, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program code. When the computer program code is executed, the method of the first aspect or any embodiment of the first aspect of the present application is performed.

[0045] This application has the following beneficial effects:

[0046] This application takes into account the problem that the accuracy of the corresponding hyperspectral remote sensing data will be affected when the surface is blocked by vegetation, buildings and other surface covers. According to the relative deviation of the concentration of heavy metal substances in the neighborhood of each monitoring point, the initial concentration corresponding to the monitoring point is corrected to obtain a more accurate reference concentration and improve the accuracy of subsequent analysis. Further, according to the characteristic that the corresponding heavy metal substances show attenuation continuity when the pollution spreads, the corresponding attenuation factor is determined according to the change of the reference concentration of each monitoring point in each neighborhood direction, so as to conduct a comprehensive analysis based on the attenuation factors of each monitoring point combined with the reference concentration of heavy metal substances at each position, and determine the more accurate final concentration of each heavy metal substance from each sewage outlet in each monitoring point, so that the pollution impact range of each sewage outlet defined by the final concentration is more accurate, and the corresponding heavy metal pollution range monitoring effect is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 A flow chart of a method for monitoring the scope of heavy metal pollution in the downstream of a mine based on GIS assistance provided by an embodiment of the present invention;

[0049] Figure 2 A structural diagram of a GIS-assisted system for monitoring the scope of heavy metal pollution in the downstream of a mine provided by an embodiment of the present invention;

[0050] Figure 3 A schematic diagram of the structure of a computer device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0051] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the specific implementation method, structure, characteristics and effects of a GIS-assisted mine downstream heavy metal pollution range monitoring method proposed by the present invention in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment, and the specific features, structures or characteristics in one or more embodiments may be combined in any suitable form. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0052] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0053] The following is a detailed description of a specific scheme of a method for monitoring the scope of heavy metal pollution in the downstream of a mine based on GIS assistance provided by the present invention in conjunction with the accompanying drawings.

[0054] This application embodiment provides a GIS-assisted method for monitoring the scope of heavy metal pollution in the downstream of a mine. Figure 1 , which shows a flow chart of a method for monitoring the scope of heavy metal pollution in the downstream of a mine based on GIS assistance provided by an embodiment of the present invention, the method comprising:

[0055] Step S101: Determine the initial concentration of each heavy metal substance corresponding to each monitoring point in the monitoring area based on the hyperspectral remote sensing data in the monitoring area centered on the mine sewage outlet.

[0056] The scenario of the embodiment of the present invention is to monitor the scope of heavy metal pollution discharged from the mine through the sewage outlet. The main purpose is to determine the pollution impact range of each heavy metal substance discharged from each sewage outlet, so as to carry out more effective heavy metal pollution range monitoring. Considering that hyperspectral remote sensing data can intuitively observe the concentration of each heavy metal substance at each location, the initial concentration of each heavy metal substance corresponding to each monitoring point in the monitoring area centered on the mine sewage outlet is determined with the help of hyperspectral remote sensing data. In a specific implementation of the embodiment of the present invention, a circular range with a radius of 20 kilometers corresponding to the mine sewage outlet as the center is used as the corresponding monitoring area. The implementer can adjust the radius size according to the specific implementation environment; and in the monitoring area, the monitoring area is traversed by airborne remote sensing to obtain the corresponding hyperspectral remote sensing data, and the acquired hyperspectral remote sensing data of the monitoring area is input into the GIS system for subsequent analysis; wherein, the spatial resolution of the hyperspectral remote sensing data is set to 30 meters, which can be adjusted according to the specific implementation environment.

[0057] After obtaining the hyperspectral remote sensing data, the hyperspectral remote sensing data is input into the trained heavy metal concentration estimation model, and the concentration of each heavy metal substance corresponding to each monitoring point in the monitoring area is output as the initial concentration.

[0058] In a specific implementation of the embodiment of the present invention, soil corresponding to the sample points is collected in the monitoring area, and the corresponding heavy metal concentration is measured; a partial least squares regression model is selected to establish a heavy metal concentration estimation model, and the spectral data corresponding to each sample point in the hyperspectral remote sensing data is used as input, and the measured heavy metal concentration is used as output to obtain a trained heavy metal concentration estimation model, and the heavy metal concentration unit is set to mg / kg, that is, the number of milligrams of pollutants contained in each kilogram of soil. In other specific implementations of the embodiment of the present invention, water samples from each sample point can also be collected to establish a heavy metal concentration estimation model.

[0059] In a specific implementation method of an embodiment of the present invention, the monitoring area grid is processed to obtain grid data corresponding to the monitoring area, and the center point of each grid in the grid data is used as the corresponding monitoring point. The size of each grid is set to a 30-meter square and the size can be adjusted at will. No further details are given here.

[0060] In a specific implementation of an embodiment of the present invention, the types of heavy metal substances are selected from lead, mercury, copper and zinc. The implementer can select them according to the types of heavy metals in the wastewater discharged from the mine in the specific implementation environment, which will not be further elaborated here.

[0061] Step S102: correcting the initial concentration according to the relative deviation of the initial concentration of various heavy metal substances in the neighborhood of each monitoring point, and determining the reference concentration of each heavy metal substance corresponding to each monitoring point.

[0062] After obtaining the heavy metal content of different geographical locations, the heavy metal content in some areas may be affected by the ground cover such as vegetation and buildings, which may affect the acquisition and accuracy of hyperspectral data. Or when heavy metal pollution spreads through groundwater, hyperspectral data cannot directly reflect the heavy metal concentration in groundwater, which makes the obtained concentration change inaccurate. Therefore, according to the continuous characteristics of concentration diffusion, the concentration is corrected according to the relative deviation of the initial concentration in the neighborhood of each monitoring point, so as to obtain a more accurate reference concentration and improve the accuracy of subsequent analysis.

[0063] Preferably, in some possible implementations of the embodiments of the present invention, the method for obtaining the reference concentration includes:

[0064] The other monitoring points within the preset neighborhood range of each monitoring point are used as the neighborhood points of each monitoring point; the initial concentration difference between each monitoring point and each corresponding neighborhood point under each heavy metal substance is calculated; the normalized value of the accumulated value of the initial concentration difference between each monitoring point and all neighborhood points under all kinds of heavy metal substances is used as the occlusion probability of each monitoring point; the monitoring points whose corresponding occlusion probability is greater than the preset occlusion threshold are used as occlusion points; the concentration of each heavy metal substance corresponding to the occlusion point is interpolated according to the initial concentration of each neighborhood point corresponding to each occlusion point through the Kriging interpolation method, and the reference concentration of each heavy metal substance at each occlusion point is obtained; the initial concentration of each heavy metal substance at other monitoring points outside the occlusion point is used as the corresponding reference concentration. In a specific implementation method of an embodiment of the present invention, the preset neighborhood range is set to 24 neighborhood ranges, and the preset occlusion threshold is set to 0.9, which can be adjusted according to the specific implementation environment.

[0065] In the process of diffusion of heavy metal pollutants, the direction of their diffusion has a certain continuity, but when it is blocked, it will cause the measured heavy metal content to be partially discontinuous. Therefore, for each monitoring point, the greater the overall difference in initial concentration between it and each monitoring point in the neighborhood, the more likely the monitoring point is to be blocked, and the corresponding initial concentration is more likely to be unreal, that is, the more correction is needed. Therefore, according to the initial concentration difference between the monitoring point and each neighborhood point, the corresponding occlusion probability is obtained; and the occlusion points with a large occlusion probability that need to be corrected are screened out through the preset occlusion threshold. And precisely because heavy metal pollutants have a point of continuity in the process of diffusion, the Kriging interpolation method is used to interpolate according to the initial concentration of each neighborhood point, so as to obtain a reference concentration that is more in line with the actual heavy metal substance concentration. It should be noted that when all neighborhood points within the preset neighborhood range of the occlusion point are occlusion points, the reference concentration of the neighborhood point is first calculated, and the reference concentration of the neighborhood point is used as the initial concentration in the interpolation process, so as to calculate the reference concentration of the corresponding occlusion point, which will not be further elaborated here.

[0066] In a specific implementation of the embodiment of the present invention, the process of obtaining the occlusion probability is expressed by the formula:

[0067]

[0068] in, is the occlusion probability of the rth monitoring point; z is the number of heavy metal substances; ω r is the number of neighboring points corresponding to the rth monitoring point; S u，r is the initial concentration of the rth monitoring point under the uth heavy metal substance; S u，r，lis the initial concentration of the lth neighborhood point corresponding to the rth monitoring point under the uth heavy metal substance; || is the absolute value symbol; Norm() is the linear normalization function.

[0069] Step S103: According to the distribution of the reference concentration, determine the attenuation factor that characterizes the attenuation trend of the reference concentration of each heavy metal substance at each monitoring point in each neighborhood direction.

[0070] After being discharged through the sewage outlet, heavy metal substances gradually flow downstream along the river, and then cause certain pollution to the land along the way and its adjacent land due to reasons such as heavy metal sedimentation. Therefore, the concentration changes of various heavy metal substances have a certain continuity and gradually decrease in the diffusion direction or transmission direction. Since the area of ​​interest corresponding to a single spectrum in the application of hyperspectral remote sensing data is relatively small, the environmental conditions in these small ranges, such as water flow rate, water depth, and pollutant concentration, are relatively uniform, so the change of pollutant concentration in a small range can be simplified to an exponential decay model. Because the water flow velocity at different locations is different and the pH value and dissolved oxygen of the water area at different locations are different, a higher water flow velocity will accelerate the diffusion and dilution of heavy metal substances, resulting in a higher attenuation factor; and some heavy metals may form precipitation under different pH conditions, resulting in a decrease in concentration, which will also affect the corresponding attenuation factor. Therefore, due to different environmental conditions, the corresponding attenuation factors of different monitoring points are also different; therefore, the attenuation factor of each monitoring point is calculated to facilitate subsequent analysis.

[0071] Taking into account the possible diffusion of heavy metal substances in all directions, that is, the attenuation of each monitoring point in each direction is different; in each neighborhood direction of each monitoring point, the more drastic the attenuation of the corresponding reference concentration of heavy metal substances, the greater the corresponding attenuation factor. Therefore, the attenuation factor of each monitoring point in each neighborhood direction is determined according to the distribution of the reference concentration.

[0072] Preferably, in some possible implementations of the embodiments of the present invention, the method for obtaining the attenuation factor includes:

[0073] Take each neighborhood direction as the target direction in turn, and take each monitoring point as the target point in turn; take the next monitoring point of the target point in the target direction as the corresponding first direction point; take the previous monitoring point of the target point in the target direction as the corresponding second direction point; under each heavy metal substance, when the reference concentration of the target point is greater than the reference concentration of the corresponding first direction point, obtain the attenuation factor of each heavy metal substance of the target point in the target direction according to the change of the reference concentration of the target point relative to the first direction point and the second direction point; under each heavy metal substance, when the reference concentration of the target point is less than or equal to the reference concentration of the corresponding first direction point, take the preset attenuation coefficient as the attenuation factor of each heavy metal substance of the target point in the target direction. In a specific implementation of the embodiment of the present invention, the preset attenuation coefficient is set to 0 and can be adjusted automatically.

[0074] Since the more drastic the attenuation of the reference concentration of heavy metal substances in each neighborhood direction, the greater the attenuation factor in the corresponding neighborhood direction. However, in the corresponding neighborhood direction, if the reference concentration does not decay but increases or remains unchanged, it means that attenuation does not exist in the corresponding direction. Therefore, when the reference concentration of the target point is less than or equal to the reference concentration of the corresponding first direction point, the corresponding attenuation factor is set to 0. The more drastic or obvious the change of the reference concentration in the corresponding neighborhood direction, the greater the corresponding attenuation factor. Therefore, the attenuation factor is determined according to the change of the reference concentration of the target point relative to the first direction point and the second direction point.

[0075] Preferably, in some possible implementations of the embodiments of the present invention, the process of obtaining the attenuation factor of each heavy metal substance at the target point in the target direction according to the reference concentration change of the target point relative to the first direction point and the second direction point includes:

[0076] For each heavy metal substance, the ratio between the reference concentration of the target point and the reference concentration of the corresponding first direction point is taken as the first concentration ratio; the ratio between the reference concentration of the corresponding second direction point and the reference concentration of the target point is taken as the second concentration ratio; the positive correlation mapping value of the mean between the first concentration ratio and the second concentration ratio is taken as the corresponding attenuation factor. That is, when the reference concentration of the target point is greater than the reference concentration of the first direction point, the attenuation factor is measured according to the reference concentration change ratio from the second direction point to the target point and from the target point to the first direction point in the corresponding neighborhood direction. The larger the mean between the corresponding first concentration ratio and the second concentration ratio, the faster the attenuation in the corresponding neighborhood direction, and the larger the corresponding attenuation factor.

[0077] In a specific implementation of the embodiment of the present invention, a method for obtaining the attenuation factor includes:

[0078]

[0079] Among them, φ v，u，r is the attenuation factor corresponding to the uth heavy metal substance at the rth monitoring point in the vth neighborhood direction; C u，r is the reference concentration of the u-th heavy metal substance corresponding to the r-th monitoring point; C″ v，u，r C′ is the reference concentration of the u-th heavy metal substance at the second direction point corresponding to the r-th monitoring point in the v-th neighborhood direction; v，u，r is the reference concentration of the uth heavy metal substance at the first direction point corresponding to the rth monitoring point in the vth neighborhood direction; lb() is a logarithmic function with a natural constant as the base. It should be noted that in order to be more in line with objective facts, when the reference concentration of the corresponding heavy metal substance at any of the target point, the corresponding first direction point and the second direction point is 0, the attenuation factor corresponding to the target point is set to 0 to prevent the denominator from being 0, which will not be further elaborated here.

[0080] Step S104: Determine the final concentration of each heavy metal substance from each sewage outlet at each monitoring point according to the attenuation factor on the pollution transfer path from each sewage outlet to each monitoring point in combination with the reference concentration.

[0081] For each sewage outlet, the concentration of the corresponding heavy metal substance is only obtained from the spectral data. In the corresponding local range, the reference concentration of the heavy metal substance not only includes its own emission amount, but also includes the concentration of heavy metal substances from other sewage outlets upstream of the sewage outlet. Therefore, the reference concentration of the monitoring point corresponding to each sewage outlet cannot represent the true concentration of each heavy metal substance discharged from the sewage outlet. However, considering that the reference concentration of heavy metal substances at each monitoring point is obtained by the joint influence of multiple sewage outlets, and the attenuation factor and the reference concentration of each monitoring point on the corresponding pollution transmission path are known, the objective function can be constructed based on these data to obtain the true concentration of each heavy metal substance discharged from each sewage outlet, so as to determine the more accurate final concentration of each heavy metal substance from each sewage outlet at each monitoring point based on the true concentration combined with the attenuation factor on the pollution transmission path.

[0082] Preferably, in some possible implementations of the embodiments of the present invention, the method for obtaining the pollution transfer path includes: planning the pollution transfer path from each sewage outlet to each monitoring point through the Floyd algorithm. That is, the shortest attenuation path corresponding to each sewage outlet pointing to each monitoring point is obtained as the corresponding pollution transfer path through the Floyd algorithm, so that the actual concentration of each heavy metal substance discharged from the sewage outlet is obtained according to the attenuation factor of each monitoring point on the path in the path direction. The total attenuation degree of each monitoring point is obtained, so that the objective function constructed according to this feature is more intuitive.

[0083] Preferably, in some possible implementations of the embodiments of the present invention, the method for obtaining the final concentration includes:

[0084] Under each heavy metal substance, the negative correlation mapping values ​​of the attenuation factors of all monitoring points in the pollution transmission path in the extension direction are cumulatively multiplied and fused to determine the cumulative attenuation coefficient from each sewage outlet to each monitoring point under each heavy metal substance; the target concentration of each heavy metal substance discharged from each sewage outlet is weighted by the cumulative attenuation coefficient to determine the final concentration of each heavy metal substance from each sewage outlet in each monitoring point. And in the method for obtaining the final concentration, the method for obtaining the target concentration includes: under each heavy metal substance, the monitoring point with a normalized value of the reference concentration greater than the preset exceeding threshold is used as the concentration exceeding point corresponding to each heavy metal substance; under each heavy metal substance, based on the least squares method, the cumulative attenuation coefficient from all sewage outlets to each concentration exceeding point is combined with the reference concentration of the corresponding concentration exceeding point to construct the objective function model under each heavy metal substance; the objective function is solved by the gradient descent method to determine the target concentration of each heavy metal substance discharged from each sewage outlet under the optimal solution. In a specific implementation of an embodiment of the present invention, the normalization method of the reference concentration adopts linear normalization, and the preset exceeding standard threshold is set to 0.8. The implementer may also use the monitoring point where the reference concentration is greater than the concentration exceeding standard threshold according to the a priori concentration exceeding standard threshold according to the specific implementation environment as the concentration exceeding standard point, which will not be further elaborated here.

[0085] First, since the reference concentration of heavy metal substances is regarded as exponential decay during the diffusion and propagation process, and considering the attenuation factor as a suppression coefficient, it is necessary to perform negative correlation mapping in advance when integrating the cumulative attenuation coefficient, so that the larger the overall attenuation factor is, the smaller the final concentration after weighting the target concentration in combination with the cumulative attenuation coefficient is; therefore, by combining the negative correlation mapping values ​​of all attenuation factors in the path extension direction in the form of cumulative multiplication, a more accurate cumulative attenuation coefficient of each sewage outlet pointing to each monitoring point is determined; and the corresponding path extension direction is the neighborhood direction corresponding to the path extension direction, so that the attenuation factor of each monitoring point can be obtained. Secondly, the true concentration of each heavy metal substance discharged from each sewage outlet is unknown, that is, the target concentration is unknown, but the cumulative attenuation coefficient of each sewage outlet pointing to each monitoring point and the reference concentration of each concentration exceeding point are truly known. Therefore, the least squares method can be used to construct the objective function model based on the cumulative attenuation coefficient from all sewage outlets to each concentration exceeding point combined with the corresponding reference concentration of the concentration exceeding point, so as to analyze the objective function in combination with the gradient descent method to determine the target concentration of each heavy metal substance discharged from each sewage outlet under the optimal solution.

[0086] Because the cumulative attenuation coefficient is known, the different target concentrations corresponding to all sewage outlets, after being propagated to each monitoring point in combination with the cumulative attenuation coefficient, the greater the deviation between the corresponding attenuated heavy metal concentration and the reference concentration, the greater the residual corresponding to the objective function, and the less likely it is to be the optimal solution; therefore, after constructing the objective function, the gradient descent method is used for iteration to obtain the target concentration under the optimal solution with the smallest residual and the most practical situation. In a specific implementation of an embodiment of the present invention, the initialization variable of the gradient descent method is set to the mean of the reference concentrations of all monitoring points adjacent to each sewage outlet, and the upper limit of the number of iterations is set to 200 to prevent the situation where the iteration cannot be stopped. It should be noted that the least squares method and the gradient descent method are prior arts well known to those skilled in the art, and are not further defined or elaborated herein.

[0087] In a specific implementation of the embodiment of the present invention, the process of obtaining the cumulative attenuation coefficient is expressed by the formula:

[0088]

[0089] Among them, ρ′ k，h，t is the cumulative attenuation coefficient from the hth sewage outlet to the tth monitoring point under the tth heavy metal substance, D h，t is the number of monitoring points on the pollution transmission path from the hth sewage outlet to the tth monitoring point; φ′ k，h，t，d is the attenuation factor of the dth monitoring point on the pollution transfer path from the hth sewage outlet to the tth monitoring point under the kth heavy metal substance in the path extension direction; exp( ) is an exponential function with a natural constant as the base; Π is the multiplication symbol.

[0090] Preferably, in some possible implementations of the embodiments of the present invention, the objective function model includes:

[0091]

[0092] Among them, L k represents the objective function value under the kth heavy metal substance; N is the number of points where the concentration exceeds the standard; C k，i is the reference concentration of the kth heavy metal substance at the i-th concentration exceeding standard point; n is the number of sewage outlets; ρ′ k，y，i is the cumulative attenuation coefficient from the yth sewage outlet to the ith concentration exceeding standard point under the kth heavy metal substance; P k，y is the target concentration of the kth heavy metal substance discharged from the yth sewage outlet.

[0093] The construction principle of the objective function based on the least squares method, C k，i is the true value,

[0094] The objective function is constructed for the estimated value. Since the reference concentration of each heavy metal substance at each concentration exceeding the standard point is obtained by the comprehensive influence of each sewage outlet, the corresponding estimated value is obtained by accumulation. It should be noted that since the least square method is a prior art well known to those skilled in the art, the significance of its objective function construction will not be further elaborated here. Further, based on the constructed objective function, the target concentration of each heavy metal substance discharged from each sewage outlet in the optimal solution is obtained by the gradient descent method. The target concentration of each heavy metal substance discharged from each sewage outlet is further weighted by the cumulative attenuation coefficient to determine the final concentration of each heavy metal substance from each sewage outlet in each monitoring point.

[0095] In a specific implementation of the embodiment of the present invention, the process of obtaining the final concentration is expressed in the formula:

[0096] Q k,h，t =ρ′ k，h，t ×P′ k，h

[0097] Among them, Q k，h，t is the final concentration of the kth heavy metal substance from the hth sewage outlet at the tth monitoring point; ρ′ k，h，t is the cumulative attenuation coefficient from the hth sewage outlet to the tth monitoring point under the kth heavy metal substance; P′ k，h It is the target concentration of the kth heavy metal substance discharged from the hth sewage outlet.

[0098] Step S105: Determine the pollution impact range of each heavy metal substance discharged from each sewage outlet according to the final concentration.

[0099] After obtaining the final concentration of each heavy metal substance from each sewage outlet at each monitoring point, the pollution impact range of each heavy metal substance discharged from each sewage outlet can be determined according to all the final concentrations corresponding to each sewage outlet, so as to carry out targeted pollution prevention and control, making the pollution prevention and control more effective and efficient, and improving the effect of heavy metal pollution range monitoring.

[0100] Preferably, in some possible implementations of the embodiments of the present invention, the method for obtaining the pollution impact range includes:

[0101] Under each heavy metal substance, the monitoring point from each sewage outlet whose final concentration is greater than the preset pollution threshold is used as the pollution monitoring point of each sewage outlet; the area formed by all pollution monitoring points corresponding to each sewage outlet is used as the pollution impact range of each heavy metal substance discharged from each sewage outlet. In a specific implementation of an embodiment of the present invention, the preset pollution threshold is set to 0.15 mg / kg. After obtaining the pollution impact range, the sewage discharge from each sewage outlet is targeted for treatment according to the size of the pollution impact range of each heavy metal substance and the concentration distribution of heavy metal substances in the pollution impact range, so as to achieve better pollution prevention and control.

[0102] In summary, a GIS-assisted method for monitoring the scope of heavy metal pollution downstream of mines first takes into account that occlusion will cause errors in some spectral data, so the initial concentration is corrected with the help of the concentration of heavy metal substances in the neighborhood of each monitoring point, and then the attenuation factor corresponding to each monitoring point is determined through the corrected reference concentration distribution, combined with the reference concentration attenuation area of ​​each heavy metal substance in the neighborhood direction; further, a comprehensive analysis is carried out based on the attenuation factor of each monitoring point combined with the reference concentration of heavy metal substances at each position, so as to more accurately determine the final concentration of each heavy metal substance from each sewage outlet in each monitoring point, so that the pollution impact range of each sewage outlet defined by the final concentration is more accurate, and the corresponding heavy metal pollution range monitoring effect is better.

[0103] This application also provides a GIS-assisted monitoring system for heavy metal pollution in the downstream of mines. Figure 2 , which shows a structural diagram of a GIS-assisted mine downstream heavy metal pollution range monitoring system provided by an embodiment of the present invention, the system includes: a data acquisition module 201, a concentration correction module 202, a first determination module 203, a second determination module 204 and a pollution impact range monitoring module 205.

[0104] The data acquisition module 201 is used to determine the initial concentration of each heavy metal substance corresponding to each monitoring point in the monitoring area based on the hyperspectral remote sensing data in the monitoring area centered on the mine sewage outlet;

[0105] The concentration correction module 202 is used to correct the initial concentration according to the relative deviation of the initial concentration of various heavy metal substances in the neighborhood of each monitoring point, and determine the reference concentration of each heavy metal substance corresponding to each monitoring point;

[0106] The first determination module 203 is used to determine the attenuation factor representing the attenuation trend of the reference concentration of each heavy metal substance at each monitoring point in each neighborhood direction according to the distribution of the reference concentration;

[0107] The second determination module 204 is used to determine the final concentration of each heavy metal substance from each sewage outlet at each monitoring point according to the attenuation factor on the pollution transfer path from each sewage outlet to each monitoring point combined with the reference concentration;

[0108] The pollution impact range monitoring module 205 is used to determine the pollution impact range of each heavy metal substance discharged from each sewage outlet according to the final concentration.

[0109] It should be noted that the system provided in the above embodiment is only illustrated by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer device is divided into different functional modules to complete all or part of the functions described above. In addition, the GIS-assisted downstream mine heavy metal pollution range monitoring system and the GIS-assisted downstream mine heavy metal pollution range monitoring method embodiment provided in the above embodiment belong to the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0110] The present application also provides a computer device. Figure 3 , which shows a schematic diagram of the structure of a computer device provided by an embodiment of the present invention, the computer device includes a memory 301, a processor 302, and a computer program 303 stored in the memory 301 and running on the processor 302, wherein when the processor 302 executes the computer program 303, the computer device can execute any one of the GIS-assisted mine downstream heavy metal pollution range monitoring methods introduced above.

[0111] An embodiment of the present application also provides a computer program product. When the computer program product is run on a computer device, the computer device can execute any of the GIS-assisted methods for monitoring the scope of heavy metal pollution downstream of a mine as described above.

[0112] An embodiment of the present application also provides a computer-readable storage medium, in which a computer program code is stored. When the computer program code is executed on a computer device, the computer device can execute any one of the GIS-assisted methods for monitoring the range of heavy metal pollution in the downstream of a mine as described above.

[0113] In the embodiments provided in the present application, it should be understood that the provided computer device, computer program product and computer-readable storage medium are all used to execute the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the methods provided above and will not be repeated here.

[0114] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0115] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A GIS-assisted method for monitoring the scope of heavy metal pollution in the downstream of a mine, characterized in that: The method comprises: Determine the initial concentration of each heavy metal substance corresponding to each monitoring point in the monitoring area based on the hyperspectral remote sensing data in the monitoring area centered on the mine sewage outlet; The initial concentration is corrected according to the relative deviation of the initial concentration of various heavy metal substances in the neighborhood of each monitoring point, and the reference concentration of each heavy metal substance corresponding to each monitoring point is determined; According to the distribution of the reference concentration, determining an attenuation factor characterizing the attenuation trend of the reference concentration of each heavy metal substance at each monitoring point in each neighborhood direction; Determine the final concentration of each heavy metal substance from each sewage outlet at each monitoring point according to the attenuation factor on the pollution transfer path from each sewage outlet to each monitoring point in combination with the reference concentration; The pollution impact range of each heavy metal substance discharged from each sewage outlet is determined according to the final concentration.

2. A GIS-assisted method for monitoring the scope of heavy metal pollution in the downstream of a mine according to claim 1, characterized in that: The method for obtaining the reference concentration includes: The other monitoring points within the preset neighborhood of each monitoring point are taken as the neighborhood points of each monitoring point; the initial concentration difference between each monitoring point and each corresponding neighborhood point under each heavy metal substance is calculated; the normalized value of the accumulated value of the initial concentration difference between each monitoring point and all neighborhood points under all heavy metal substances is taken as the occlusion probability of each monitoring point; the monitoring point whose corresponding occlusion probability is greater than the preset occlusion threshold is taken as the occlusion point; The concentration of each heavy metal substance corresponding to the blocked point is interpolated according to the initial concentration of each neighborhood point corresponding to each blocked point through the Kriging interpolation method to obtain the reference concentration of each heavy metal substance at each blocked point; the initial concentration of each heavy metal substance at other monitoring points outside the blocked point is used as the corresponding reference concentration.

3. The GIS-assisted method for monitoring the scope of heavy metal pollution in the downstream of a mine according to claim 1 is characterized in that: The method for obtaining the attenuation factor includes: Each neighborhood direction is taken as the target direction in turn, and each monitoring point is taken as the target point in turn; the next monitoring point of the target point in the target direction is taken as the corresponding first direction point; the previous monitoring point of the target point in the target direction is taken as the corresponding second direction point; Under each heavy metal substance, when the reference concentration of the target point is greater than the reference concentration of the corresponding first direction point, the attenuation factor of each heavy metal substance at the target point in the target direction is obtained according to the change of the reference concentration of the target point relative to the first direction point and the second direction point; Under each heavy metal substance, when the reference concentration of the target point is less than or equal to the reference concentration of the corresponding first direction point, the preset attenuation coefficient is used as the attenuation factor of each heavy metal substance of the target point in the target direction.

4. A GIS-assisted method for monitoring the scope of heavy metal pollution in the downstream of a mine according to claim 3, characterized in that: The method for obtaining the attenuation factor of each heavy metal substance at the target point in the target direction according to the reference concentration change of the target point relative to the first direction point and the second direction point includes: For each heavy metal substance, the ratio between the reference concentration of the target point and the corresponding reference concentration of the first direction point is taken as the first concentration ratio; the ratio between the reference concentration of the corresponding second direction point and the reference concentration of the target point is taken as the second concentration ratio; the positive correlation mapping value of the mean between the first concentration ratio and the second concentration ratio is taken as the corresponding attenuation factor.

5. The GIS-assisted method for monitoring the scope of heavy metal pollution in the downstream of a mine according to claim 1 is characterized in that: The method for obtaining the pollution transmission path includes: The pollution transfer path from each sewage outlet to each monitoring point is planned using the Floyd algorithm.

6. A GIS-assisted method for monitoring the scope of heavy metal pollution in the downstream of a mine according to claim 1, characterized in that: The method for obtaining the final concentration includes: Under each heavy metal substance, the negative correlation mapping values ​​of the attenuation factors of all monitoring points in the pollution transmission path in the extension direction of the path are cumulatively multiplied and fused to determine the cumulative attenuation coefficient from each sewage outlet to each monitoring point under each heavy metal substance; The target concentration of each heavy metal substance discharged from each sewage outlet is weighted by the cumulative attenuation coefficient to determine the final concentration of each heavy metal substance from each sewage outlet at each monitoring point.

7. A GIS-assisted method for monitoring the scope of heavy metal pollution in the downstream of a mine according to claim 6, characterized in that: The method for obtaining the target concentration includes: Under each heavy metal substance, the monitoring point where the normalized value of the reference concentration is greater than the preset exceeding standard threshold is taken as the concentration exceeding standard point corresponding to each heavy metal substance; Under each heavy metal substance, the objective function model under each heavy metal substance is constructed based on the least square method according to the cumulative attenuation coefficient from all sewage outlets to each concentration exceeding the standard point combined with the reference concentration of the corresponding concentration exceeding the standard point; The objective function is solved by the gradient descent method to determine the target concentration of each heavy metal substance discharged from each sewage outlet under the optimal solution.

8. A GIS-assisted method for monitoring the scope of heavy metal pollution in the downstream of a mine according to claim 7, characterized in that: The objective function model includes: Among them, L k represents the objective function value under the kth heavy metal substance; N is the number of points where the concentration exceeds the standard; C k，i is the reference concentration of the kth heavy metal substance at the i-th concentration exceeding standard point; n is the number of sewage outlets; ρ′ k，y，i is the cumulative attenuation coefficient from the yth sewage outlet to the ith concentration exceeding standard point under the kth heavy metal substance; P k，y is the target concentration of the kth heavy metal substance discharged from the yth sewage outlet.

9. The GIS-assisted method for monitoring the scope of heavy metal pollution in the downstream of a mine according to claim 1, characterized in that: The method for obtaining the pollution impact range includes: For each heavy metal substance, the monitoring point from each sewage outlet where the final concentration is greater than the preset pollution threshold is used as the pollution monitoring point of each sewage outlet; the area formed by all the pollution monitoring points corresponding to each sewage outlet is used as the pollution impact range of each heavy metal substance discharged from each sewage outlet.

10. The GIS-assisted method for monitoring the scope of heavy metal pollution in the downstream of a mine according to claim 3, characterized in that: The preset attenuation coefficient is set to 0.

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