An integrated land and underwater terrain mapping method and system

Abstract

The present invention provides a method and system for integrated mapping of onshore and underwater terrain. In the method, taking the waterline terrain data as a reference benchmark, the onshore terrain data and the underwater terrain data are mapped into the same coordinate system for fusion and unification, so as to obtain three-dimensional terrain data covering both onshore and underwater areas, ensuring the integrity and accuracy of large-scale restoration of the real onshore and underwater cross-regional spatial terrain.

Description

Technical Field

[0001] The present invention relates to the field of map surveying and mapping, and in particular to a method and system for integrated surveying and mapping of land and underwater terrain. Background Art

[0002] In recent years, with the increasing demand for large-scale topographic maps in the fine design of water environment treatment and restoration projects. At present, the surveying and mapping method of large-scale topographic maps mainly relies on manual data collection in the field using devices such as GPS-RTK and total stations by manual labor, and then in-office processing and production. This operation mode has low efficiency, long time span, high cost, large manual labor intensity, there are certain safety risks, and the production progress is also affected by the weather during the operation, which can no longer meet the social needs. How to improve work efficiency, reduce production costs, and reduce the field workload is an urgent requirement for obtaining large-scale topographic maps today.

[0003] Since unmanned aerial vehicles (UAVs) have the characteristics of being flexible, economical and convenient, and can conveniently obtain high-resolution images, using UAV aerial survey to measure large-scale topographic maps has low cost, short construction period and high accuracy, which can greatly reduce the field workload, thereby improving production efficiency and shortening the construction period. However, UAVs are only suitable for the collection of land terrain data and cannot obtain effective underwater terrain data.

[0004] Underwater terrain survey of river and lake waters is a specific survey in engineering survey, which measures the plane position and elevation underwater of rivers, lakes, reservoirs, harbors and coastal waters for the surveying and mapping work of drawing underwater topographic maps. The main content is to establish a control network on land and conduct underwater topographic surveying and mapping. Underwater topographic surveying and mapping includes sounding point positioning, water depth measurement, water level observation and mapping, etc. The methods of sounding point positioning include section wire method, forward intersection method of theodolite or plane table, back intersection method of sextant, polar coordinate method of total station speedometer, radio positioning method, underwater acoustic positioning and differential GPS positioning method, etc. Water depth measurement uses instruments such as sounding rods, sounding hammers and echo sounders. The bottom elevation is calculated based on the results of water depth measurement and water level observation, and finally the underwater terrain is represented by isobaths (or contour lines).

[0005] At present, underwater terrain survey and land terrain survey are independent of each other, so effective integration cannot be carried out. Summary of the Invention

[0006] In order to solve the defect that land terrain survey and underwater terrain survey are independent of each other and cannot be integrated in the above-mentioned prior art, the present invention proposes a method and system for integrated surveying and mapping of land and underwater terrain.

[0007] The present invention provides a method for integrated mapping of onshore and underwater terrain, which can obtain three-dimensional terrain data covering both onshore and underwater areas, ensuring the integrity and accuracy of large-scale restoration of the real terrain.

[0008] A method for integrated mapping of onshore and underwater terrain includes the following steps:

[0009] S1. Obtain onshore terrain data G, waterline terrain data W, and underwater terrain data U;

[0010] G = {g1, g2, g3,..., gm,..., gM}, 1 ≤ m ≤ M, gm = [x gm , y gm , z gm

[0011] W = {w1, w2, w3,..., wn,..., wN}, 1 ≤ n ≤ N, wn = [x wn , y wn , z wn

[0012] U = {u1, u2, u3,..., uk,..., uK}, 1 ≤ k ≤ K, uk = [x uk , y uk , z uk

[0013] gm represents the coordinate points obtained from onshore mapping, (x gm , y gm ) represents the two-dimensional coordinates of the coordinate point gm on the digital map, z gm represents the elevation, M represents the number of coordinate points obtained from onshore mapping, and m represents the coordinate point serial number;

[0014] wn represents the coordinate points obtained from mapping on the waterline, (x wn , y wn ) represents the two-dimensional coordinates of the coordinate point wn on the digital map, z wn represents the elevation, N represents the number of coordinate points obtained from mapping on the waterline, and n represents the coordinate point serial number; uk represents the coordinate points obtained from underwater mapping; (x uk , y uk ) represents the two-dimensional coordinates of the coordinate point uk on the digital map, z uk represents the elevation, K represents the number of coordinate points obtained from underwater mapping, and k represents the coordinate point serial number;

[0015] S2. Set the affine transformation model;

[0016] S3. Solve the parameters of the affine transformation model in S2 based on the corresponding points in the onshore terrain data G and the waterline terrain data W to obtain the first affine transformation model f1 with fixed parameters; solve the parameters of the affine transformation model set in S2 based on the corresponding points in the underwater terrain data U and the waterline terrain data W to obtain the second affine transformation model f2 with fixed parameters; that is:

[0017] When A and B are corresponding points, it means that the actual feature points corresponding to A and B are the same;

[0018] When g i ∈G, w i' ∈W and g i and w i' are corresponding points,

[0019] then

[0020] When u j ∈U, w j' ∈W and u j and w j' are corresponding points,

[0021] then

[0022] In the above formula, i, j, i', and j' all represent ordinals, 1 ≤ i ≤ M, 1 ≤ j ≤ k, 1 ≤ i' ≤ N, 1 ≤ j' ≤ N;

[0023] represents the three-dimensional coordinate measurement value of the i-th measurement point g i in the onshore terrain data G, represents the three-dimensional coordinate measurement value of the i'-th measurement point w i ' in the waterline terrain data W;

[0024] represents the three-dimensional coordinate measurement value of the j-th measurement point u j in the underwater terrain data U, represents the three-dimensional coordinate measurement value of the j'-th measurement point w j ' in the waterline terrain data W;

[0025] S4. Transform the onshore terrain data G into G' according to the first affine transformation model f1, and transform the underwater terrain data U into U' according to the second affine transformation model f2;

[0026] That is:

[0027]

[0028] S5. Combine the waterline terrain data W to divide the land area D and the water area E, and determine the land area G” and the water area U” according to the following formula;

[0029] G” = G' ∩ D, U” = U' ∩ E;

[0030] S6. Obtain the integrated mapping data A = G” ∪ U”, and draw a two-dimensional map and / or a three-dimensional map according to the data A.

[0031] Preferably, the affine transformation model set in S2 is a 7-parameter affine transformation model.

[0032] Preferably, in S3, the least squares method is used to solve the parameters of the affine transformation model in combination with the input-output error to fix the first affine transformation model and the second affine transformation model.

[0033] Preferably, the affine transformation model set in S2 is as follows:

[0034]

[0035] Among them, (x e , y e , z e ) represents the three-dimensional coordinates of any collected data point, and (x e ', y e ', z e ) represents the three-dimensional coordinates after the three-dimensional coordinates (x e , y e , z e ) are transformed by the affine transformation model; dx is the translation parameter in the x direction, dy is the translation parameter in the y direction, dz is the translation parameter in the z direction; ε x is the rotation parameter in the x direction, ε y is the rotation parameter in the y direction, ε z is the rotation parameter in the z direction, and η is the scale change parameter.

[0036] Preferably, the waterline terrain data W is obtained by surveying with a differential GPS receiving system.

[0037] Preferably, the homologous points in S3 are manually marked.

[0038] Another object of the present invention provides an integrated land and underwater terrain mapping system for implementing the above-mentioned integrated land and underwater terrain mapping method.

[0039] An integrated land and underwater terrain mapping system includes a data receiving module, a processor, and a memory. The data receiving module is used to obtain land terrain data G, water edge terrain data W, and underwater terrain data U. A computer program is stored in the memory, and the processor is respectively connected to the data receiving module and the memory. The processor is used to execute the computer program to implement the integrated land and underwater terrain mapping method.

[0040] Preferably, it further includes an onshore UAV mapping subsystem, a water area mapping subsystem, and a differential GPS receiving system;

[0041] The onshore UAV mapping subsystem is used for onshore mapping to obtain land terrain data G; the water area mapping subsystem is used for water area mapping to obtain underwater terrain data U; the differential GPS receiving system is used for mapping the water edge area to obtain water edge terrain data W;

[0042] The data receiving module is respectively connected to the UAV mapping subsystem, the water area mapping subsystem, and the differential GPS receiving system to collect the land terrain data G collected by the UAV mapping subsystem, the water edge terrain data W collected by the water area mapping subsystem, and the underwater terrain data U collected by the differential GPS receiving system.

[0043] The advantages of the present invention are as follows:

[0044] (1) Currently, land terrain data is generally obtained by UAV orthophoto mapping, and underwater terrain data is generally obtained through acoustic devices carried by shipborne or unmanned vessels. Through the present invention, with the water edge terrain data as the coordinate reference, the land terrain data and the underwater terrain data are mapped into the same coordinate system for fusion and unification, and finally three-dimensional terrain data covering both land and water is obtained, making map mapping more unified and accurate.

[0045] (2) In the present invention, a 7-parameter affine transformation model is designed to transform the land terrain data and the underwater terrain data, taking into account the translation and rotation during the coordinate data transformation, thus ensuring the accuracy of the coordinate transformation and laying a foundation for the accuracy of the finally obtained map.

[0046] (3) In the present invention, both the first affine transformation model and the second affine transformation model are obtained based on the 7-parameter affine transformation model, which is conducive to the unification of the transformed coordinate data; and the parameter solution of the first affine transformation model and the parameter solution of the second affine transformation model are independent of each other, ensuring the accurate mapping of the land terrain data and the underwater terrain data.

[0047] (4) In the present invention, the water edge terrain data W is obtained by mapping through the differential GPS receiving system. With the high-precision water edge terrain data W, the accurate transformation of the land terrain data and the underwater terrain data is ensured, thereby ensuring the accuracy of the finally obtained integrated mapping data A.

[0048] (5) In the present invention, homologous points are manually marked, and then the first affine transformation model and the second affine transformation model are solved based on the homologous points, with high reliability.

[0049] (6) Through the present invention, onshore terrain data and underwater terrain data obtained in any manner can be unified and fused, with a wide range of applications. Description of the Drawings

[0050] Figure 1 is a flowchart of a method for integrated mapping of onshore and underwater areas proposed by the present invention;

[0051] Figure 2 is a diagram of the parameter settings for UAV aerial photography in the experimental area of Example 1;

[0052] Figure 2 In which, P represents the forward overlap part, and Q represents the side overlap part;

[0053] Figure 3 (a) in is a diagram of the parallel route settings for underwater terrain detection in Example 2;

[0054] Figure 3 (b) in is a diagram of the "zigzag" route settings for underwater terrain detection in Example 2;

[0055] Figure 4 is a diagram of the layout of water edge terrain measurement points in Example 3;

[0056] Figure 5 is a diagram of homologous points in different data planes and the water edge area in Example 4;

[0057] Figure 6 (a) in is a diagram of the onshore terrain data G" after affine transformation in Example 4;

[0058] Figure 6 (b) in is a diagram of the underwater terrain data U" after affine transformation in Example 4;

[0059] Figure 6 (c) in is a diagram of the integrated mapping data A in Example 5;

[0060] Figure 6 (d) in is a 3D map constructed according to the integrated mapping data A in Example 5. Detailed Embodiments

[0061] Glossary of Terms:

[0062] Homonymous points: Assume that the land terrain data G contains a land measurement point A, and the water edge terrain data W contains a measurement point B on the water edge. If the measurement point A and the measurement point B correspond to the same feature point in the real scene map, then the measurement point A and the measurement point B are homonymous points; similarly, assume that the underwater terrain data U contains an underwater measurement point C, and the water edge terrain data W contains a measurement point D on the water edge. If the measurement point C and the measurement point D correspond to the same feature point in the real scene map, then the measurement point C and the measurement point D are homonymous points.

[0063] The integrated land and underwater topographic mapping method provided by this embodiment needs to collect land terrain data G, water edge terrain data W, and underwater terrain data U, and then perform affine transformation on the land terrain data G and the underwater terrain data U and fuse them according to the Figure 1 flow chart shown.

[0064] Example 1: Acquisition of land terrain data G

[0065] The main applicable object of the integrated land and underwater topographic mapping method provided by this embodiment is small water bodies. Therefore, in this embodiment, a light and small unmanned aerial vehicle is selected to collect land terrain data.

[0066] In this embodiment, the acquisition of land terrain data strictly complies with the relevant regulations of the national airspace control. The specific flight parameter requirements are as follows: the heading overlap is between 60% and 80%, the side overlap is 30% to 50%, the flight altitude is 50 to 120 meters, the ground resolution value is better than 20 cm, and the flight line design is Figure 2 the parallel flight line shown, as Figure 2 shown. Specifically, when implementing, the flight line can also adopt a "zigzag" flight line.

[0067] The land terrain data G consists of M land measurement points, denoted as: G = {g1, g2, g3,..., gm,..., gM}; where gm = [x gm , y gm , z gm , m represents the serial number, 1 ≤ m ≤ M, gm represents the m-th land measurement point, and [x gm , y gm , z gm represents the xyz three-dimensional coordinate measurement value of the measurement point gm.

[0068] Example 2: Acquisition of underwater terrain data U

[0069] In this embodiment, the underwater terrain data is collected by a ship or an unmanned ship. Specifically, a ship or an unmanned ship device with longitude and latitude measurement and depth sounding functions is selected, such as an unmanned ship equipped with an acoustic device for depth sounding. Specifically, when implementing, the on-site collection route of the unmanned ship needs to lay out a depth collection route according to the actual situation of the water body to be collected. The recommended route setting is a parallel route (asFigure 3 (a) in Figure 3 and the "zigzag" route (such as

[0070] The underwater terrain data consists of K underwater measurement points, denoted as: U = {u1, u2, u3, …, uk, …, uK}; where, uk = [x uk , y uk , z uk , k represents the serial number, 1 ≤ k ≤ K, uk represents the kth underwater measurement point, and [x uk , y uk , z uk represents the xyz three-dimensional coordinate measurement value of the measurement point uk.

[0071] Example 3: Acquisition of waterline terrain data W

[0072] In this example, a differential GPS receiving system is used to obtain the geodetic elevation of the waterline, and then the normal height of the measurement point is obtained through the seven-parameter or elevation fitting method. Regarding the measurement and acquisition of the normal height, it is necessary to follow the relevant operation standards and specifications of the surveying and mapping industry. Here, the layout principles and methods for collecting waterline terrain data are mainly introduced. In this example, the measurement points of the waterline terrain data need to be evenly distributed on the waterline of the measured water body. Measurement points need to be densely arranged at key inflection points and areas with large terrain amplitude changes. The number of measurement points needs to be greater than 9. The specific distribution of the waterline terrain data measurement points can refer to Figure 4 . The data set of the waterline elevation measurement points, that is, the waterline terrain data, is denoted as W = {w1, w2, w3, …, wn, …, wN}, where, wn = [x wn , y wn , z wn , 1 ≤ n ≤ N, n represents the ordinal number, N represents the number of waterline elevation measurement points, wn represents the nth measurement point on the waterline, and [x wn , y wn , z wn represents the xyz three-dimensional coordinate measurement value of the measurement point wn.

[0073] Topographic mapping on land, underwater topographic mapping, and waterline extraction are all conventional technical means in the art. The acquisition of these three is not the innovation point of the present invention. The innovation point of the present invention lies in the fusion of the land terrain data G obtained by topographic mapping on land and the underwater terrain data U obtained by underwater topographic mapping. Therefore, the present invention does not elaborate on the acquisition of the land terrain data G, the underwater terrain data U, and the waterline terrain data W. Those skilled in the art should know that the integrated land and underwater topographic mapping method provided by the present invention is applicable to the land terrain data G and the underwater terrain data U obtained by any method.

[0074] As can be seen from Embodiment 1 and Embodiment 3, due to different topographic environments, different mapping methods are used for onshore mapping and underwater mapping. Therefore, onshore mapping and underwater mapping actually correspond to two different map systems. In this embodiment, the onshore topographic data G and the underwater topographic data U are affine-transformed with the water edge topographic data W as a transition, so as to map the onshore topographic data G and the underwater topographic data U into the same map system, realizing integrated onshore and underwater mapping.

[0075] Embodiment 4: Establishment of an affine model

[0076] In this embodiment, according to the homologous points in the onshore topographic data G and the water edge topographic data W, a first affine transformation model f1 that can map the onshore topographic data G to the three-dimensional coordinate system where the water edge topographic data W is located is determined. According to the homologous points in the underwater topographic data U and the water edge topographic data W, a second affine transformation model f2 that can map the underwater topographic data U to the three-dimensional coordinate system where the water edge topographic data W is located is determined.

[0077] The solution process of the first affine transformation model f1 is as follows:

[0078] Obtain a homologous point data set T1 in the onshore topographic data G and the water edge topographic data W. The homologous point data set T1 is composed of multiple data point pairs (g i , w i' ), where g i ∈G, w i' ∈W and g i and w i' are homologous points.

[0079] Then

[0080] The error of the first affine transformation model is:

[0081]

[0082] In this embodiment, the first affine transformation model adopts a 7-parameter affine transformation model, and formula (1) is specifically expressed as follows:

[0083]

[0084] In formula (1), dx is the translation parameter in the x direction, dy is the translation parameter in the y direction, and dz is the translation parameter in the z direction; ε x is the rotation parameter in the x direction, ε y is the rotation parameter in the y direction, ε z is the rotation parameter in the z direction, and η is the scale change parameter.

[0085] Combining formula (2) and formula (1-1), it can be seen that:

[0086]

[0087] Combining the errors (E xi , E yi , E zi ) corresponding to all homologous points in the homologous point dataset T1, E xi , E yi , E zi respectively represent the offset errors of the coordinate points before and after transformation in the xyz-axis directions; the seven parameters in formula (1-1) are solved using the least squares method, and the solution results are: d x = d x1 , d y = d y1 , d z = d z1 , η = η1, ε x = ε x1 , ε y = ε y1 , ε z = ε z1 , that is, the first affine transformation model is determined as:

[0088]

[0089] In formula (1-2), (x gm , y gm , z gm ) are the three-dimensional coordinate measurement values of the measurement point g m in the land terrain data G, and (x gm ', y gm ', z gm ) represent the three-dimensional coordinate data of the measurement point g m after affine transformation, denoted as g m = (x gm , y gm , z gm ), g m ' = (x gm ', y gm ', z gm ').

[0090] In this way, according to the above formula (1-2), the land terrain data G can be mapped into the coordinate system of the water edge terrain data W to obtain the land terrain data G' with the same coordinate system as the water edge terrain data W, G' = {g1', g2', g3', ……, gM'}.

[0091] The solution process of the second affine transformation model f2:

[0092] Obtain the dataset T2 of corresponding points in the underwater terrain data U and the waterline terrain data W. The dataset T2 of corresponding points consists of multiple data point pairs (u j , w j' ), where u j ∈U, w j' ∈W and u j and w j are corresponding points.

[0093] Then

[0094] The error of the first affine transformation model is:

[0095]

[0096] In this embodiment, the second affine transformation model adopts a 7-parameter affine transformation model, and formula (3) is specifically expressed as follows:

[0097]

[0098] In formula (3), dx is the translation parameter in the x direction, dy is the translation parameter in the y direction, and dz is the translation parameter in the z direction; ε x is the rotation parameter in the x direction, ε y is the rotation parameter in the y direction, ε z is the rotation parameter in the z direction, and η is the scale change parameter.

[0099] Combining formula (4) and formula (3-1) shows that:

[0100]

[0101] Combining the errors (E xj , E xj , E xj ) corresponding to all the corresponding points in the dataset T2 of corresponding points. E xi , E yi , and E zi respectively represent the offset errors of the coordinate points before and after the transformation in the xyz axis directions. Using the least squares method to solve the 7 parameters in formula (3-1), the solution results are: d x = d x2 , d y = d y2 , d z = d z2 , η = η2, ε x = ε x2 , ε y = ε y2 , ε z = ε z2, that is, determining the second affine transformation model as:

[0102]

[0103] In formula (3-2), [x uk , y uk , z uk is the three-dimensional coordinate measurement value of the measurement point u k in the underwater terrain data U, [x uk ', y uk ', z uk '] represents the three-dimensional coordinate data of the measurement point u k after affine transformation, denoted as uk = [x uk , y uk , z uk , uk' = [x uk ', y uk ', z uk '].

[0104] In this way, according to the above formula (3-2), the underwater terrain data U can be mapped into the coordinate system of the waterline terrain data W to obtain the underwater terrain data U' with the same coordinate system as the waterline terrain data W, U' = {u1', u2', u3', …, uK'}.

[0105] Specifically, the parameters of the first affine transformation model and the second affine transformation model obtained by specific solution according to the acquisition parameters in the embodiments shown in the drawings of the present invention are shown in Table 1 below:

[0106] Table 1: Parameter statistics table of the models in the embodiments shown in the drawings

[0107]

[0108]

[0109] Example 5: Fusion of land terrain data G and underwater terrain data U

[0110] The land terrain data G obtained from land mapping is transformed into G' through the first affine transformation model f1 shown in formula (1-2), G' = {g1', g2', g3', …, gm', …, gM'}, gm' = [x gm ', y gm ', z gm '], 1 ≤ m ≤ M.

[0111] The underwater terrain data U obtained from underwater mapping is transformed into U' through the second affine transformation model f2 shown in formula (3-2), U' = {u1', u2', u3', …, uk', …, uK'}, uk' = [x uk',y uk ',z uk '], 1 ≤ k ≤ K.

[0112] In this way, the onshore terrain data G' and the underwater terrain data U' are in the same three-dimensional coordinate system, laying a foundation for the fusion of the two.

[0113] In this embodiment, in order to ensure the accurate fusion of the onshore terrain data G' and the underwater terrain data U', it is necessary to remove duplicates from the onshore terrain data G' and the underwater terrain data U' first.

[0114] In this embodiment, according to the waterline terrain data W, the onshore area D and the water area E are determined, and it is further determined that only the data points belonging to the onshore area D in the onshore terrain data G' are valid onshore terrain data, and it is determined that only the data points in the data domain water area E in the underwater terrain data U' are valid underwater terrain data. The valid onshore terrain data is denoted as the onshore area G”, that is, the onshore area G” is composed of the data points existing in the onshore terrain data G and located outside or on the closed coil surrounded by the waterline terrain data W. For details, please refer to Figure 6 (a) in. The valid underwater terrain data is denoted as the water area U”, that is, the water area U” is composed of the data points existing in the underwater terrain data U and located inside the closed coil surrounded by the waterline terrain data W. For details, please refer to Figure 6 (b) in.

[0115] That is: G” = G' ∩ D, U” = U' ∩ E (5)

[0116] In this embodiment, the finally obtained integrated surveying and mapping data A = G” ∪ U”, as shown in Figure 6 (c) in. In this way, the onshore terrain data included in G” and the underwater terrain data included in U” are in the same coordinate system space, that is, the coordinate system space where the waterline terrain data W is located, ensuring the same benchmark of the finally obtained integrated surveying and mapping data A, and ensuring the integrity and accuracy of the large-scale restoration of the real terrain; at the same time, the duplicate removal process of the fusion data is realized through formula (5), ensuring the uniqueness of the surveying and mapping points in the integrated surveying and mapping data A, and further ensuring the accuracy and reliability of the integrated surveying and mapping data A.

[0117] In this way, after obtaining the integrated surveying and mapping data A, a two-dimensional map and the three-dimensional map shown in Figure 6 (d) in can be drawn according to the integrated surveying and mapping data A to realize the high-precision modeling reproduction of the real map.

[0118] Embodiment 6: An onshore and underwater terrain integrated mapping system

[0119] An integrated land and underwater topographic mapping system proposed in this embodiment includes a data receiving module, a processor, and a memory. The data receiving module is used to collect land topographic data G, water edge line topographic data W, and underwater topographic data U. A computer program is stored in the memory. The processor is respectively connected to the data receiving module and the memory. The processor is used to execute the computer program to implement the integrated land and underwater topographic mapping method, so as to obtain integrated mapping data A, and draw two-dimensional maps and three-dimensional maps according to requirements.

[0120] In this embodiment, the land topographic data G can be provided by the land UAV mapping subsystem, and the land UAV mapping subsystem can be specifically implemented as a mapping UAV. The underwater topographic data U can be provided by the water area mapping subsystem, and the water area mapping subsystem can be specifically implemented as a mapping unmanned ship equipped with an acoustic sounding device. The water edge line topographic data W is used as a reference datum. In this embodiment, in order to ensure the accuracy of the coordinates of the water edge line topographic data W, a differential GPS receiving system is used to map the water edge line area. The data receiving module respectively collects the data collected by the UAV mapping subsystem, the water area mapping subsystem, and the differential GPS receiving system, that is: land topographic data G, water edge line topographic data W, and underwater topographic data U.

[0121] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An integrated land and underwater topographic mapping method, characterized in that, It includes the following steps: S1. Obtain the land terrain data G, the waterline terrain data W, and the underwater terrain data U; G = {g1, g2, g3, …, gm, …, gM}, 1 ≤ m ≤ M, gm = [x gm , y gm , z gm ​ W = {w1, w2, w3, …, wn, …, wN}, 1 ≤ n ≤ N, wn = [x wn , y wn , z wn ​ U = {u1, u2, u3, …, uk, …, uK}, 1 ≤ k ≤ K, uk = [x uk , y uk , z uk ​ gm represents the coordinate points obtained from land surveying and mapping, (x gm , y gm ) represents the two-dimensional coordinates of the coordinate point gm on the digital map, z gm represents the elevation, M represents the number of coordinate points obtained from land surveying and mapping, and m represents the coordinate point serial number; wn represents the coordinate points obtained from mapping on the water edge line, (x wn , y wn ) represents the two-dimensional coordinates of the coordinate point wn on the digital map, z wn represents the elevation, N represents the number of coordinate points obtained from mapping on the water edge line, n represents the serial number of the coordinate point; uk represents the coordinate points obtained from underwater mapping; (x uk , y uk ) represents the two-dimensional coordinates of the coordinate point uk on the digital map, z uk represents the elevation, K represents the number of coordinate points obtained from underwater mapping, k represents the serial number of the coordinate point; S2. Set up an affine transformation model; S3. Solve the parameters of the affine transformation model in S2 according to the homologous point pairs in the land terrain data G and the waterline terrain data W to obtain the first affine transformation model f1 with fixed parameters; solve the parameters of the affine transformation model set in S2 according to the homologous point pairs in the underwater terrain data U and the waterline terrain data W to obtain the second affine transformation model f2 with fixed parameters; that is: When A and B are homologous points, it means that the corresponding real scene feature points of A and B are the same; When g i ∈ G, w i' ∈ W and g i and w i' are homologous points, Then When u j ∈U, w j' ∈W and u j and w j' are homologous points, Then In the above formula, i, j, i', and j' all represent ordinals, 1 ≤ i ≤ M, 1 ≤ j ≤ k, 1 ≤ i' ≤ N, 1 ≤ j' ≤ N; Denote the three-dimensional coordinate measurement value of the i-th measurement point g in the onshore terrain data G i ; Denote the three-dimensional coordinate measurement value of the i'-th measurement point w in the waterline terrain data W i' ; Denote the three-dimensional coordinate measurement value of the j-th measurement point u in the underwater terrain data U j . Denote the three-dimensional coordinate measurement value of the j'-th measurement point w' in the waterline terrain data W j ; S4. Transform the land terrain data G into G' according to the first affine transformation model f1, and transform the underwater terrain data U into U' according to the second affine transformation model f2; That is: S5. Divide the land area D and the water area E in combination with the waterline terrain data W, and determine the land area G” and the water area U” according to the following formula; G” = G' ∩ D, U” = U' ∩ E; S6. Obtain the integrated surveying and mapping data A = G” ∪ U”, and draw a two-dimensional map and / or a three-dimensional map according to the data A.

2. The integrated land and underwater topographic mapping method according to claim 1, characterized in that, The affine transformation model set in S2 is a seven-parameter affine transformation model.

3. The integrated land and underwater topographic mapping method according to claim 2, characterized in that, In S3, the least squares method is used to solve the parameters of the affine transformation model in combination with the input-output error to fix the first affine transformation model and the second affine transformation model.

4. The integrated land and underwater topographic mapping method according to claim 2, characterized in that, The affine transformation model set in S2 is as follows: Among them, (x e , y e , z e ) represents the three-dimensional coordinates of any data point collected, (x e ', y e ', z e ) represents the three-dimensional coordinates after the three-dimensional coordinates (x e , y e , z e ) are transformed by the affine transformation model; dx is the translation parameter in the x direction, dy is the translation parameter in the y direction, and dz is the translation parameter in the z direction; ε x is the rotation parameter in the x direction, ε y is the rotation parameter in the y direction, ε z is the rotation parameter in the z direction, and η is the scale change parameter.

5. The integrated land and underwater topographic mapping method according to claim 1, characterized in that, The waterline terrain data W is obtained by surveying with a differential GPS receiving system.

6. The integrated land and underwater topographic mapping method according to claim 1, characterized in that, In S3, the homologous points are manually marked.

7. An integrated land and underwater topographic mapping system, characterized in that, It includes a data receiving module, a processor, and a memory. The data receiving module is used to obtain the land terrain data G, the waterline terrain data W, and the underwater terrain data U. A computer program is stored in the memory. The processor is respectively connected to the data receiving module and the memory. The processor is used to execute the computer program to implement the land and underwater terrain integrated mapping method according to any one of claims 1 to 6.

8. The integrated land and underwater topographic mapping system according to claim 7, wherein It further includes a land unmanned aerial vehicle surveying and mapping subsystem, a water area surveying and mapping subsystem, and a differential GPS receiving system; The land unmanned aerial vehicle surveying and mapping subsystem is used for land surveying to obtain the land terrain data G; the water area surveying and mapping subsystem is used for water area surveying to obtain the underwater terrain data U; the differential GPS receiving system is used for surveying the waterline area to obtain the waterline terrain data W; The data receiving module is respectively connected to the unmanned aerial vehicle surveying and mapping subsystem, the water area surveying and mapping subsystem, and the differential GPS receiving system to collect the land terrain data G collected by the unmanned aerial vehicle surveying and mapping subsystem, the waterline terrain data W collected by the water area surveying and mapping subsystem, and the underwater terrain data U collected by the differential GPS receiving system.

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