A method for determining the true source of a river
By constructing a three-dimensional river network map within the river basin and combining various objective indicators and weight calculations, the problem of subjective dependence in determining the true source of a river is solved, and a scientific and accurate determination of the true source of a river is achieved.
Patent Information
- Application Number
- CN202610514739.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-17
- Publication Date
- 2026-06-30
AI Technical Summary
Current technologies rely too heavily on subjective judgment to determine the true source of rivers, leading to disputes and lacking a scientific, unified, and operable method for determination.
Using a basin vector boundary file and digital elevation model, the three-dimensional skeleton lines of the main stream and tributaries are determined by a three-dimensional river network map. By combining Euclidean distance, water volume contribution, flow direction straightness and altitude advantage, the weights are obtained by the analytic hierarchy process (AHP) to calculate the positive source probability of the tributaries and finally determine the positive source of the river.
It enables the scientific and objective determination of the true source of a river, eliminates subjective bias, breaks through the limitations of traditional two-dimensional planar analysis, accurately restores the true spatial structure of the river, and avoids deviations caused by topography.
Smart Images
Figure CN122310012A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of hydrological science and technology, and in particular relates to a method for determining the true source of a river. Background Technology
[0002] The source of a river is the starting point of its hydrological system and ecological life, and its scientific definition has significant value for both natural research and geographical identification. Through multiple rounds of systematic scientific investigations, the true sources of major rivers such as the Yangtze and Yellow Rivers have been successively verified. The true source of the Yangtze is the Tuotuo River, and the true source of the Yellow River is the Yueguzongliequ River. The determination of a river's true source generally follows the principle of determining the longest river. However, runoff and gradient are also important characteristics of rivers. Water volume dominates the river's hydrological morphology, the ecological support capacity of the basin, and the overall development pattern of the river system. Gradient is an auxiliary indicator for judging river morphology; the greater the gradient, the closer it is to the natural morphology of a mountainous river source, and the more likely it possesses the hydrodynamic and developmental conditions of a main river. Furthermore, the complexity of the topography and hydrological characteristics of different river basins leads to disputes over the definition of the true source of some rivers. Therefore, it is urgent to construct a scientific, unified, and operable method for determining the true source of rivers from a natural science perspective, providing professional technical support for resolving disputes over river source tracing. Summary of the Invention
[0003] In view of the above-mentioned shortcomings in the prior art, the present invention provides a method for determining the true source of a river, which solves the problem that the river source in the prior art relies too much on subjective judgment.
[0004] To achieve the aforementioned objectives, the present invention employs the following technical solution: a method for determining the true source of a river, comprising: Extract the digital elevation model within the watershed area based on the watershed vector boundary file; Based on the digital elevation model within the watershed, the three-dimensional skeleton lines of the main stream and tributaries of the river to be determined are obtained, resulting in a three-dimensional river network map; In the three-dimensional river network map, the set of distant candidate tributaries is determined based on the Euclidean distance from the confluence point of the main stream and the distance from the confluence point of the main stream in the skeleton direction, respectively. Quantify the water volume contribution of each tributary, and determine the candidate tributary set based on the water volume contribution of each tributary; Calculate the three-dimensional angle between each tributary and the main stream, quantify the straightness of each tributary's flow direction based on the three-dimensional angle, and determine the candidate tributary set based on the straightness of each tributary's flow direction. Quantify the elevation advantage of each tributary and determine the set of candidate tributaries based on the elevation advantage; Determine whether the intersection of the distant candidate tributary set, the water volume candidate tributary set, the flow direction candidate tributary set, and the altitude candidate tributary set is empty. If it is, integrate the distant candidate tributary set, the water volume candidate tributary set, the flow direction candidate tributary set, and the altitude candidate tributary set to obtain the final candidate set. Otherwise, take the intersection of the distant candidate tributary set, the water volume candidate tributary set, the flow direction candidate tributary set, and the altitude candidate tributary set as the final candidate set. Collect existing data on rivers with confirmed positive sources, and use the analytic hierarchy process (AHP) to obtain the weights of distance, water volume contribution, flow direction straightness, and elevation advantage. The probability of each tributary as a positive source in the final candidate set is calculated based on the weights of distance, water volume contribution, flow direction straightness, and altitude advantage. The tributary with the highest probability of being the primary source is taken as the primary source of the undetermined river.
[0005] Furthermore, obtaining the set of remote candidate tributaries specifically involves: Calculate the Euclidean distance between the upstream endpoint of each tributary and the confluence of the main stream; Based on the distance between the upstream endpoint of each tributary and the confluence point of the main stream in the skeleton direction:
[0006] in, for and This represents the distance along the skeletal direction. For the first The upstream endpoint of a tributary; The point where the main stream flows into the river has the following coordinates: ; For the first The x-coordinate of each river channel skeleton node; This represents the total number of nodes in the river channel framework. For the first The ordinate of each river channel skeleton node; For the first Vertical coordinates of each river channel skeleton node; Based on the length of the main stream, a distance threshold is set, and tributaries whose Euclidean distance between the upstream endpoint and the main stream confluence point or whose distance between the upstream endpoint and the main stream confluence point in the skeleton direction is greater than the distance threshold are selected to obtain the first set of tributaries. By removing tributaries from the first set of tributaries that do not meet the constraints of length, flow direction, altitude, and hydrological stability, a set of distant candidate tributaries is obtained.
[0007] Furthermore, the flow direction constraint is that the angle between the tributary flow direction and the main stream flow direction is less than a set angle threshold; the elevation constraint is that the elevation of the far end of the tributary is greater than an elevation threshold; the length constraint is that the total length of the tributary is greater than a set length threshold; and the hydrological stability constraint is that the tributary does not dry up throughout the year.
[0008] Furthermore, the expression for the water volume contribution of each tributary is as follows:
[0009] in, For the first The water volume contribution of each tributary; The weighting of the runoff ratio; For the first The average annual runoff of the tributary; The average annual runoff of the main stream; For the first The drainage area of the tributary; This represents the total area of the entire basin.
[0010] Furthermore, the determination of the candidate tributary set based on the water volume contribution of each tributary specifically involves: Tributaries whose water contribution is greater than the contribution threshold are selected as the second set of tributaries; By removing tributaries from the second tributary set that do not meet the constraints of length, flow direction, altitude, and hydrological stability, a candidate tributary set is obtained.
[0011] Furthermore, the expression for the straightness of the flow direction of each tributary is as follows:
[0012] in, For the first The straightness of the flow direction of the tributary; For the first The three-dimensional angle between the direction of flow of the tributary and the main stream; This represents the upper limit of the three-dimensional included angle; It is the inverse cosine function; For the first The three-dimensional flow direction vector of a tributary; This is the three-dimensional flow direction vector of the main stream; It is the absolute value; For the first The x-coordinate of the point where the downstream of a tributary meets the main stream; For the first The x-coordinate of the far upstream endpoint of a tributary; For the first The ordinate of the point where the downstream section of a tributary meets the main stream; For the first The ordinate of the far upstream endpoint of a tributary; For the first Vertical coordinates of the point where the downstream section of a tributary meets the main stream; For the first The vertical coordinate of the far upstream endpoint of a tributary; The x-coordinate of the point where the main stream flows into the river; The x-coordinate of the far upstream end of the main stream; The ordinate of the point where the main stream flows into the river; The ordinate is the ordinate of the far upstream end of the main stream; The vertical coordinate of the point where the main stream flows into the river; The vertical coordinate is the furthest point upstream of the main stream.
[0013] Furthermore, the determination of the candidate tributary set based on the straightness of the flow direction of each tributary specifically involves: Select tributaries whose flow straightness is greater than the lower limit of straightness as the third tributary set; By removing tributaries from the third tributary set that do not meet the length, elevation, and hydrological stability constraints, a candidate tributary set is obtained.
[0014] Furthermore, the quantification of the elevation advantage of each tributary and the determination of a set of candidate elevation tributaries based on the elevation advantage specifically involves: Quantifying the elevational advantages of each tributary:
[0015] in, For the first The elevation advantage of a tributary; Weighted by altitude; For the first The elevation of the far end of the upstream section of a tributary; It is the highest elevation in the entire basin; For the first The elevation difference between the far upstream end of a tributary and the point where it joins the main stream; This represents the maximum elevation difference across the entire basin. Select tributaries whose elevation advantage is greater than the lower limit of elevation advantage as the fourth set of tributaries; By removing tributaries from the fourth tributary set that do not meet the length constraint, flow direction constraint, and hydrological stability constraint, a flow direction candidate tributary set is obtained.
[0016] Furthermore, the expression for the positive source probability of each tributary is:
[0017] in, For the first The possibility of a positive source for a tributary; Weights for distance terms; Weighting of water volume contribution; Weighting for flow straightness; Weighting based on altitude advantage; for and Euclidean distance; for and This represents the distance along the skeletal direction. For the first The upstream endpoint of a tributary; The point where the main stream flows into the river has the following coordinates: ; For the first The water volume contribution of each tributary; For the first The straightness of the flow direction of the tributary; For the first The tributary has an elevation advantage.
[0018] The beneficial effects of this invention are as follows: It integrates four core criteria: distance, water volume, flow direction, and altitude. When extracting a single criterion, the other criteria serve as constraints, thus resolving the controversy caused by the single standard of "only distance / only size / only flow / only altitude". It eliminates subjective judgment bias: It uses a hierarchical analysis method driven by historical data to determine the weights, and objective data corrects subjective bias. It conducts full-process calculations based on a three-dimensional river network skeleton, breaking through the limitations of traditional two-dimensional planar analysis, accurately restoring the true spatial structure of the river, and avoiding river network deviation caused by plain / mountainous terrain. Attached Figure Description
[0019] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation
[0020] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.
[0021] like Figure 1 As shown, in one embodiment of the present invention, a method for determining the true source of a river includes: Extract the digital elevation model within the watershed area based on the watershed vector boundary file; Based on the digital elevation model within the watershed, the three-dimensional skeleton lines of the main stream and tributaries of the river to be determined are obtained, resulting in a three-dimensional river network map; In the three-dimensional river network map, the set of distant candidate tributaries is determined based on the Euclidean distance from the confluence point of the main stream and the distance from the confluence point of the main stream in the skeleton direction, respectively. Quantify the water volume contribution of each tributary, and determine the candidate tributary set based on the water volume contribution of each tributary; Calculate the three-dimensional angle between each tributary and the main stream, quantify the straightness of each tributary's flow direction based on the three-dimensional angle, and determine the candidate tributary set based on the straightness of each tributary's flow direction. Quantify the elevation advantage of each tributary and determine the set of candidate tributaries based on the elevation advantage; Determine whether the intersection of the distant candidate tributary set, the water volume candidate tributary set, the flow direction candidate tributary set, and the altitude candidate tributary set is empty. If it is, integrate the distant candidate tributary set, the water volume candidate tributary set, the flow direction candidate tributary set, and the altitude candidate tributary set to obtain the final candidate set. Otherwise, take the intersection of the distant candidate tributary set, the water volume candidate tributary set, the flow direction candidate tributary set, and the altitude candidate tributary set as the final candidate set. Collect existing data on rivers with confirmed positive sources, and use the analytic hierarchy process (AHP) to obtain the weights of distance, water volume contribution, flow direction straightness, and elevation advantage. The probability of each tributary as a positive source in the final candidate set is calculated based on the weights of distance, water volume contribution, flow direction straightness, and altitude advantage. The tributary with the highest probability of being the primary source is taken as the primary source of the undetermined river.
[0022] In this embodiment, the three-dimensional skeleton is a skeleton line with elevation data; the confluence point of the main stream is the location where the main stream flows into the river or sea.
[0023] The specific steps for obtaining the remote candidate tributary set are as follows: Calculate the Euclidean distance between the upstream endpoint of each tributary and the confluence of the main stream; Based on the distance between the upstream endpoint of each tributary and the confluence point of the main stream in the skeleton direction:
[0024] in, for and This represents the distance along the skeletal direction. For the first The upstream endpoint of a tributary; The point where the main stream flows into the river has the following coordinates: ; For the first The x-coordinate of each river channel skeleton node; This represents the total number of nodes in the river channel framework. For the first The ordinate of each river channel skeleton node; For the first Vertical coordinates of each river channel skeleton node; In this embodiment, the straight-line spatial distance from the tributary endpoint to the river mouth is calculated, reflecting the absolute spatial distance of the source area. This distance is accumulated segment by segment along the three-dimensional river network framework to accurately reflect the actual flow path length of the river, serving as the core quantitative indicator for "the greatest distance from the source." Simultaneously, both "absolute spatial distance" and "actual flow path" are considered to avoid misjudgments caused by a single distance. Three-dimensional calculation replaces traditional two-dimensional planar distances, closely conforming to real terrain and eliminating deviations caused by elevation.
[0025] Based on the length of the main stream, a distance threshold is set, and tributaries whose Euclidean distance between the upstream endpoint and the main stream confluence point or whose distance between the upstream endpoint and the main stream confluence point in the skeleton direction is greater than the distance threshold are selected to obtain the first set of tributaries. By removing tributaries from the first set of tributaries that do not meet the constraints of length, flow direction, altitude, and hydrological stability, a set of distant candidate tributaries is obtained.
[0026] The flow direction constraint is that the angle between the tributary flow direction and the main stream flow direction is less than a set angle threshold; the elevation constraint is that the elevation of the far end of the tributary is greater than an elevation threshold; the length constraint is that the total length of the tributary is greater than a set length threshold; and the hydrological stability constraint is that the tributary does not dry up throughout the year.
[0027] The expression for the water volume contribution of each tributary is as follows:
[0028] in, For the first The water volume contribution of each tributary; The weighting of the runoff ratio; For the first The average annual runoff of the tributary; The average annual runoff of the main stream; For the first The drainage area of the tributary; This represents the total area of the entire basin.
[0029] It integrates two core indicators: runoff (directly reflecting water volume contribution) and watershed area (indirectly reflecting water collection capacity); it eliminates the influence of dimensions through normalization and quantifies the water volume contribution of tributaries to the main stream as the contribution degree in the [0,1] interval; the weighting coefficient is 0.6 by default, giving priority to reflecting the core role of runoff, and can be adjusted according to the characteristics of the watershed, such as increasing it to 0.7 in plain areas.
[0030] It covers both direct and indirect water flow, avoiding the limitations of a single flow indicator in areas without data; after normalization, tributaries of different basins and scales can be compared horizontally; the weights can be adaptively adjusted to suit basins with different recharge types such as glacial meltwater and rainwater.
[0031] The process of determining the candidate tributary set based on the water volume contribution of each tributary is as follows: Tributaries whose water contribution is greater than the contribution threshold are selected as the second set of tributaries; By removing tributaries from the second tributary set that do not meet the constraints of length, flow direction, altitude, and hydrological stability, a candidate tributary set is obtained.
[0032] The expression for the straightness of the flow direction of each tributary is:
[0033] in, For the first The straightness of the flow direction of the tributary; For the first The three-dimensional angle between the direction of flow of the tributary and the main stream; This represents the upper limit of the three-dimensional included angle; It is the inverse cosine function; For the first The three-dimensional flow direction vector of a tributary; This is the three-dimensional flow direction vector of the main stream; It is the absolute value; For the first The x-coordinate of the point where the downstream of a tributary meets the main stream; For the first The x-coordinate of the far upstream endpoint of a tributary; For the first The ordinate of the point where the downstream section of a tributary meets the main stream; For the first The ordinate of the far upstream endpoint of a tributary; For the first Vertical coordinates of the point where the downstream section of a tributary meets the main stream; For the first The vertical coordinate of the far upstream endpoint of a tributary; The x-coordinate of the point where the main stream flows into the river; The x-coordinate of the far upstream end of the main stream; The ordinate of the point where the main stream flows into the river; The ordinate is the ordinate of the far upstream end of the main stream; The vertical coordinate of the point where the main stream flows into the river; The vertical coordinate is the furthest point upstream of the main stream.
[0034] Based on a three-dimensional river network framework, three-dimensional flow direction vectors of tributaries and main streams are constructed. The three-dimensional angle is calculated using the vector dot product to quantify the consistency of flow direction between tributaries and main streams. After normalization, straightness is obtained; the smaller the three-dimensional angle, the higher the straightness, and the more it conforms to the "flow direction follows the grain" criterion. This method breaks through the limitations of traditional two-dimensional planar angles and accurately reflects the consistency of flow direction under real terrain conditions. A 90° angle can directly eliminate false sources such as those with backflow or sharp turns, thus improving the rationality of the candidate set.
[0035] The determination of the candidate tributary set based on the straightness of the flow direction of each tributary is specifically as follows: Select tributaries whose flow straightness is greater than the lower limit of straightness as the third tributary set; By removing tributaries from the third tributary set that do not meet the length, elevation, and hydrological stability constraints, a candidate tributary set is obtained.
[0036] The process of quantifying the elevation advantage of each tributary and determining a set of candidate tributaries based on these advantages is as follows: Quantifying the elevational advantages of each tributary:
[0037] in, For the first The elevation advantage of a tributary; Weighted by altitude; For the first The elevation of the far end of the upstream section of a tributary; It is the highest elevation in the entire basin; For the first The elevation difference between the far upstream end of a tributary and the point where it joins the main stream; This represents the maximum elevation difference across the entire basin. It integrates two major indicators: absolute altitude (source elevation, reflecting "altitude as the only factor") and relative elevation difference (the difference in elevation from the source to the confluence point, reflecting the potential energy of the water flow); after normalization, the altitude advantage is obtained, with a default weighting coefficient of 0.7, which prioritizes the core role of absolute altitude, and can be adjusted to 0.8 for glacier areas.
[0038] It eliminates pseudo-sources that are "high in altitude but short in distance and have small elevation difference", and only retains source areas with high altitude and sufficient water catchment potential energy; it takes into account both absolute elevation and water catchment potential energy; the weight can be adapted to different terrains such as glacier areas, mountainous areas, and plains.
[0039] Select tributaries whose elevation advantage is greater than the lower limit of elevation advantage as the fourth set of tributaries; By removing tributaries from the fourth tributary set that do not meet the length constraint, flow direction constraint, and hydrological stability constraint, a flow direction candidate tributary set is obtained.
[0040] The expression for the positive source probability of each tributary is:
[0041] in, For the first The possibility of a positive source for a tributary; Weights for distance terms; Weighting of water volume contribution; Weighting for flow straightness; Weighting based on altitude advantage; for and Euclidean distance; for and This represents the distance along the skeletal direction. For the first The upstream endpoint of a tributary; The point where the main stream flows into the river has the following coordinates: ; For the first The water volume contribution of each tributary; For the first The straightness of the flow direction of the tributary; For the first The tributary has an elevation advantage.
[0042] In this embodiment, existing data on rivers with confirmed positive sources are collected. Based on this data, the weights of distance, water volume contribution, flow direction straightness, and elevation advantage are obtained using the Analytic Hierarchy Process (AHP). The average contribution of the four criteria is calculated based on historical data of undisputed positive source rivers globally and nationally. The objective contribution ratio is used to replace the traditional subjective scoring of 1-9 in the AHP, and a pairwise comparison judgment matrix is constructed.
Claims
1. A method for determining the true source of a river, characterized in that, include: Extract the digital elevation model within the watershed area based on the watershed vector boundary file; Based on the digital elevation model within the watershed, the three-dimensional skeleton lines of the main stream and tributaries of the river to be determined are obtained, resulting in a three-dimensional river network map; In the three-dimensional river network map, the set of distant candidate tributaries is determined based on the Euclidean distance from the confluence point of the main stream and the distance from the confluence point of the main stream in the skeleton direction, respectively. Quantify the water volume contribution of each tributary, and determine the candidate tributary set based on the water volume contribution of each tributary; Calculate the three-dimensional angle between each tributary and the main stream, quantify the straightness of each tributary's flow direction based on the three-dimensional angle, and determine the candidate tributary set based on the straightness of each tributary's flow direction. Quantify the elevation advantage of each tributary and determine the set of candidate tributaries based on the elevation advantage; Determine whether the intersection of the distant candidate tributary set, the water volume candidate tributary set, the flow direction candidate tributary set, and the altitude candidate tributary set is empty. If it is, integrate the distant candidate tributary set, the water volume candidate tributary set, the flow direction candidate tributary set, and the altitude candidate tributary set to obtain the final candidate set. Otherwise, take the intersection of the distant candidate tributary set, the water volume candidate tributary set, the flow direction candidate tributary set, and the altitude candidate tributary set as the final candidate set. Collect existing data on rivers with confirmed positive sources, and use the analytic hierarchy process (AHP) to obtain the weights of distance, water volume contribution, flow direction straightness, and elevation advantage. The probability of each tributary as a positive source in the final candidate set is calculated based on the weights of distance, water volume contribution, flow direction straightness, and altitude advantage. The tributary with the highest probability of being the primary source is taken as the primary source of the undetermined river.
2. The method for determining the true source of a river according to claim 1, characterized in that, The specific steps for obtaining the remote candidate tributary set are as follows: Calculate the Euclidean distance between the upstream endpoint of each tributary and the confluence of the main stream; Based on the distance between the upstream endpoint of each tributary and the confluence point of the main stream in the skeleton direction: in, for and This represents the distance along the skeletal direction. For the first The upstream end of a tributary; The point where the main stream flows into the river has the following coordinates: ; For the first The x-coordinate of each river channel skeleton node; This represents the total number of nodes in the river channel framework. For the first The ordinate of each river channel skeleton node; For the first Vertical coordinates of each river channel skeleton node; Based on the length of the main stream, a distance threshold is set, and tributaries whose Euclidean distance between the upstream endpoint and the main stream confluence point or whose distance between the upstream endpoint and the main stream confluence point in the skeleton direction is greater than the distance threshold are selected to obtain the first set of tributaries. By removing tributaries from the first set of tributaries that do not meet the constraints of length, flow direction, altitude, and hydrological stability, a set of distant candidate tributaries is obtained.
3. The method for determining the true source of a river according to claim 2, characterized in that, The flow direction constraint is that the angle between the tributary flow direction and the main stream flow direction is less than a set angle threshold; the elevation constraint is that the elevation of the far end of the tributary is greater than an elevation threshold; the length constraint is that the total length of the tributary is greater than a set length threshold; and the hydrological stability constraint is that the tributary does not dry up throughout the year.
4. The method for determining the true source of a river according to claim 1, characterized in that, The expression for the water volume contribution of each tributary is as follows: in, For the first The water volume contribution of each tributary; The weighting of the runoff ratio; For the first The average annual runoff of the tributary; The average annual runoff of the main stream; For the first The drainage area of the tributary; This represents the total area of the entire basin.
5. The method for determining the true source of a river according to claim 4, characterized in that, The process of determining the candidate tributary set based on the water volume contribution of each tributary is as follows: Tributaries whose water contribution is greater than the contribution threshold are selected as the second set of tributaries; By removing tributaries from the second tributary set that do not meet the constraints of length, flow direction, altitude, and hydrological stability, a candidate tributary set is obtained.
6. The method for determining the true source of a river according to claim 1, characterized in that, The expression for the straightness of the flow direction of each tributary is as follows: in, For the first The straightness of the flow direction of the tributary; For the first The three-dimensional angle between the direction of flow of the tributary and the main stream; This represents the upper limit of the three-dimensional included angle; It is the inverse cosine function; For the first The three-dimensional flow direction vector of a tributary; This represents the three-dimensional flow direction vector of the main stream; It is the absolute value; For the first The x-coordinate of the point where the downstream of a tributary meets the main stream; For the first The x-coordinate of the far upstream endpoint of a tributary; For the first The ordinate of the point where the downstream section of a tributary meets the main stream; For the first The ordinate of the far upstream endpoint of a tributary; For the first Vertical coordinates of the point where the downstream section of a tributary meets the main stream; For the first The vertical coordinate of the far upstream endpoint of a tributary; The x-coordinate of the point where the main stream flows into the river; The x-coordinate of the far upstream end of the main stream; The ordinate of the point where the main stream flows into the river; The ordinate is the ordinate of the far upstream end of the main stream; The vertical coordinate of the point where the main stream flows into the river; The vertical coordinate is the furthest point upstream of the main stream.
7. The method for determining the true source of a river according to claim 1, characterized in that, The determination of the candidate tributary set based on the straightness of the flow direction of each tributary is specifically as follows: Select tributaries whose flow straightness is greater than the lower limit of straightness as the third tributary set; By removing tributaries from the third tributary set that do not meet the length, elevation, and hydrological stability constraints, a candidate tributary set is obtained.
8. The method for determining the true source of a river according to claim 1, characterized in that, The process of quantifying the elevation advantage of each tributary and determining a set of candidate tributaries based on these advantages is as follows: Quantifying the elevational advantages of each tributary: in, For the first The elevation advantage of a tributary; Weighted by altitude; For the first The elevation of the far end of the upstream section of a tributary; It is the highest elevation in the entire basin; For the first The elevation difference between the far upstream end of a tributary and the point where it joins the main stream; This represents the maximum elevation difference across the entire basin. Select tributaries whose elevation advantage is greater than the lower limit of elevation advantage as the fourth set of tributaries; By removing tributaries from the fourth tributary set that do not meet the length constraint, flow direction constraint, and hydrological stability constraint, a flow direction candidate tributary set is obtained.
9. The method for determining the true source of a river according to claim 1, characterized in that, The expression for the positive source probability of each tributary is: in, For the first The possibility of a positive source for a tributary; Weights for distance terms; Weighting of water volume contribution; Weighting for flow straightness; Weighting based on altitude advantage; for and Euclidean distance; for and This represents the distance along the skeletal direction. For the first The upstream end of a tributary; The point where the main stream flows into the river has the following coordinates: ; For the first The water volume contribution of each tributary; For the first The straightness of the flow direction of the tributary; For the first The tributary has an elevation advantage.