A method for constructing an unrefined area land-sea integrated digital elevation model and a related system

Abstract

The application discloses a method for constructing a land-sea integrated digital elevation model in an unmeasured area and a related system, relates to the field of ocean surveying and mapping and land-sea integrated digital elevation model construction, and mainly comprises the following steps: delimiting the range of the unmeasured area according to land-sea integrated elevation data, extracting elevation point data within a set distance outside the periphery of the unmeasured area, performing a water depth interpolation operation on the unmeasured area by using a quadratic thin-plate spline function or a fourth-order response surface analysis function according to the extracted elevation point data within the set distance outside the periphery of the unmeasured area, constructing an irregular triangle net according to the elevation point data after the water depth interpolation operation, and manufacturing a land-sea integrated digital elevation model according to the irregular triangle net. The application can realize the construction of a land-sea integrated digital elevation model in an unmeasured area based on the elevation point data in the periphery of the unmeasured area under the condition of multi-source heterogeneous fusion.

Description

Technical Field

[0001] This invention relates to the fields of marine surveying and mapping and the construction of integrated land-sea digital elevation models, and particularly to a method and related system for constructing integrated land-sea digital elevation models in areas with inaccurate survey data. Background Technology

[0002] Currently, the construction of integrated land-sea digital elevation models is based on raw data that meets grid accuracy requirements. This is achieved through interpolation methods such as constructing Deloni irregular triangulation networks, inverse distance weighting algorithms, and Kriging interpolation. However, in current marine surveying processes, due to the complexity of sea areas, the unpredictability of underwater conditions, and the presence of ecological protection zones, prohibited measurement zones, and dangerous zones, water depth measurements cannot cover the entire sea area. Under these circumstances, the aforementioned integrated land-sea digital elevation model construction has the following shortcomings:

[0003] (1) High density of raw data is required. Only with a sufficiently high density can the construction of the land-sea integrated digital elevation model better express the seabed topography. Otherwise, the constructed digital elevation model will be seriously inconsistent with the actual terrain and the difference will be large, thus failing to meet the accuracy requirements.

[0004] (2) The digital elevation model was implemented using common interpolation methods, but outliers (such as reefs and islands) were not removed, resulting in abnormalities in the construction results of the digital elevation model.

[0005] (3) For areas where no precise survey has been conducted (due to maritime navigation safety considerations, ships cannot reach these areas), using the Deloni irregular triangular mesh interpolation method to construct a digital elevation model (DEM) for these areas would result in an unreasonable mesh shape and excessive errors. If the inverse distance weighted algorithm and Kriging interpolation method are used to construct the DEM for these areas, the influence of distance is too great, and it cannot well represent the seabed topography and geomorphology, resulting in excessive errors. Moreover, beyond a certain distance, the constructed DEM has no reference value. Based on this, for large-scale areas where no precise survey has been conducted, the main approach is to abandon them and mark them with the words "No Precise Survey Area" as an identifier. However, this approach is no longer sufficient to meet actual needs. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method and related system for constructing an integrated land-sea digital elevation model for an unrefined survey area. This method enables the construction of an integrated land-sea digital elevation model for an unrefined survey area based on elevation point data from the periphery of the unrefined survey area, under the premise of multi-source heterogeneous fusion.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides a method for constructing an integrated land-sea digital elevation model for an area with inaccurate survey data, comprising:

[0009] A depth datum conversion model is established to convert ocean depth data into land elevation data based on the 1985 National Height Datum.

[0010] Acquire land topography data and ocean topography data, and perform multi-source heterogeneous data fusion operation on the land topography data and ocean topography data to generate integrated land and sea elevation data;

[0011] The extent of the unmeasured area is determined based on the integrated land and sea elevation data.

[0012] Extract elevation data from points within a set distance outside the unmeasured area;

[0013] Based on the extracted elevation point data within a set distance outside the unmeasured area, the water depth of the unmeasured area is interpolated using a quadratic thin plate spline function or a fourth-order response surface analysis function. The elevation point data of the unmeasured area is then fused and updated based on the water depth interpolation results.

[0014] Based on the merged and updated elevation point data, an irregular triangular network is constructed, and a land-sea integrated digital elevation model is created based on the irregular triangular network.

[0015] Secondly, this invention provides a system for constructing an integrated land-sea digital elevation model for an area with inaccurate survey data, comprising:

[0016] The data acquisition unit is used to perform the following steps:

[0017] A depth datum conversion model is established to convert ocean depth data into land elevation data based on the 1985 National Height Datum.

[0018] Acquire land topography data and ocean topography data, and perform multi-source heterogeneous data fusion operation on the land topography data and ocean topography data to generate integrated land and sea elevation data;

[0019] The data processing unit is used to perform the following steps:

[0020] The extent of the unmeasured area is determined based on the integrated land and sea elevation data.

[0021] Extract elevation data from points within a set distance outside the unmeasured area;

[0022] Based on the extracted elevation point data within a set distance outside the unmeasured area, the water depth of the unmeasured area is interpolated using a quadratic thin plate spline function or a fourth-order response surface analysis function. The elevation point data of the unmeasured area is then fused and updated based on the water depth interpolation results.

[0023] Based on the merged and updated elevation point data, an irregular triangular network is constructed, and a land-sea integrated digital elevation model is created based on the irregular triangular network.

[0024] Thirdly, the present invention also provides an electronic device, including a processor and a memory;

[0025] The memory is used to store programs;

[0026] The processor executes the program to implement the method described above.

[0027] Fourthly, the present invention also provides a computer-readable storage medium storing a program that is executed by a processor to implement the methods described above.

[0028] Fifthly, the present invention also provides a computer program product or computer program comprising computer instructions stored in a computer-readable storage medium. A processor of a computer device can read the computer instructions from the computer-readable storage medium and execute the computer instructions to cause the computer device to perform the preceding method.

[0029] Compared with the prior art, the beneficial effects of this invention are as follows: Based on the multi-source heterogeneous fusion, this invention can realize the construction of a land-sea integrated digital elevation model for the unrefined survey area based on the elevation point data of the periphery of the unrefined survey area. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a flowchart illustrating the method for constructing an integrated land-sea digital elevation model in an area not accurately surveyed according to an embodiment of the present invention.

[0032] Figure 2 This is a schematic diagram of the unprecise measurement area under multi-source heterogeneous fusion according to an embodiment of the present invention;

[0033] Figure 3 This is a flowchart of the method for delineating unprecise survey areas in the land-sea integrated system according to an embodiment of the present invention;

[0034] Figure 4 This is a flowchart of the elevation value interpolation method for unmeasured areas according to an embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of the system structure in an embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of an electronic device in an embodiment of the present invention. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0038] Example:

[0039] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, in the embodiments of this invention are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0040] Example 1

[0041] Please see the appendix Figure 1 The implementation examples will be based on the appendix. Figure 1 A detailed explanation is provided. A method for constructing an integrated land-sea digital elevation model for an area with inaccurate survey data may specifically include the following steps:

[0042] Step 101: Establish a depth datum conversion model to convert ocean depth data into land elevation data based on the 1985 National Height Datum.

[0043] This step mainly aims to unify the elevation datum. In daily surveying and mapping work, different elevation datums are used for land and sea. The land part uses the 1985 National Elevation Datum, while the sea part uses the depth datum. Therefore, in the process of building an integrated land and sea digital elevation model, the water depth data is converted into elevation data based on the 1985 National Elevation Datum through the depth datum conversion model, thus completing the unification of the elevation datum.

[0044] Step 102: Acquire land topography data and ocean topography data, and perform multi-source heterogeneous data fusion operation on the land topography data and ocean topography data to generate integrated land and sea elevation data.

[0045] In this step, land topographic data and marine topographic data are inconsistent in terms of data acquisition and data structure. The two different types of data are converted into formats and processed into physical entities to complete the fusion processing of multi-source heterogeneous land and sea data.

[0046] It should be noted that the land topographic data corresponds to elevation data, and the datum is the 1985 National Elevation Datum; the marine topographic data corresponds to water depth data, and the datum is the depth datum; the depth datum conversion model is used to convert the depth datum to the 1985 National Elevation Datum.

[0047] For example, based on step 101, multi-source heterogeneous data fusion is performed. Since land topographic data is acquired in various ways, including but not limited to UAV (manned aircraft) airborne laser measurement, field GPS measurement, and total station analytical measurement, etc., and marine depth measurement commonly uses methods such as depth sounding rods, single-beam measurement, and multi-beam measurement, the different data acquisition methods result in differences in coordinate systems, storage methods, and data structures between land and marine topographic data. Therefore, multi-source heterogeneous data fusion processing is required. Since this embodiment of the invention focuses on multi-source heterogeneous data fusion of integrated land and sea topographic data, and in the surveying and mapping geographic information industry, elevation points are commonly used to represent topographic data, the work required at the level of multi-source heterogeneous topographic data fusion includes:

[0048] The first step is to unify the plane coordinate system and the elevation coordinate system. Specific methods include the Bursa three-dimensional seven-parameter method and the Bursa two-dimensional seven-parameter method to transform land and ocean elevation data into a unified plane coordinate system.

[0049] Furthermore, data structure conversion is required. Since land elevation point data can be stored in various formats such as las, dwg, txt, and shp, resulting in diverse data structures, while seabed bathymetry data is mostly stored in las and txt formats, data structure conversion is used to unify the storage of land elevation point data and seabed bathymetry data into a unified shp or database data structure.

[0050] Furthermore, the attribute structure is unified, and the land elevation point data and seabed bathymetry data are stored through the (X,Y,Z) attribute structure, where X represents the horizontal coordinate, Y represents the vertical coordinate, and Z represents the normal height based on the 1985 National Height Datum.

[0051] Furthermore, data merging involves combining land elevation point data and seabed bathymetry data after unifying their attribute structures, thereby achieving the fusion of multi-source heterogeneous land and sea data.

[0052] In some embodiments, the order of steps 101 and 102 can be interchanged.

[0053] Step 103: Delineate the area of ​​the unmeasured zone based on the integrated land and sea elevation data.

[0054] This step mainly involves delineating the area of ​​the inaccurate survey. Please refer to the appendix. Figure 2 A schematic diagram of the unresolved survey area under multi-source heterogeneous fusion. Combined with the land-sea integrated elevation data after multi-source heterogeneous data fusion in step 102, the unresolved survey area is identified according to the following formula (1). When the distance between two elevation points is... When the spacing is less than or equal to the required spacing of the mapping scale, the area is considered a normal area; when the distance between two elevation points... When the spacing exceeds the required spacing of the mapping scale, the area is considered an area where inaccurate surveying has occurred.

[0055] Formula (1)

[0056] Represents the distance between two elevation points. For mapping scale.

[0057] Furthermore, the delineation of the unrefined survey area is based on formula (1). Please refer to the appendix. Figure 3 The flowchart for delineating the inaccurate survey area of ​​the integrated land and sea survey is as follows: There are two methods for delineating the inaccurate survey area of ​​the integrated land and sea survey: one is to manually draw the area by professional technicians according to the judgment principle of formula (1). This method requires high technical skills, involves a large workload, and may result in omissions. However, this method is fast and accurate when dealing with the delineation of the inaccurate survey area in a small local area. The other method is to automatically obtain the area by computer, which is suitable for delineating the inaccurate survey area in a large area. The work required includes:

[0058] The first step is to extract the outer boundary of the integrated land-sea elevation data, which can be determined by the work area or automatically obtained by a computer.

[0059] Furthermore, the integrated land-sea elevation data buffer processing involves buffering each point in the integrated land-sea elevation data, with the distance reference for the buffer being... (in (Consistent with the above formula (1)).

[0060] Furthermore, the buffer merging process merges the above-mentioned land-sea integrated elevation data buffer processing results to form the area covered by the land-sea integrated elevation data (normal area). This area meets the relevant mapping requirements and can be treated as a normal area.

[0061] Furthermore, spatial analysis (intersection inversion) is performed by combining the outer boundary of the integrated land and sea elevation data and the area covered by the integrated land and sea elevation data (normal area). This means extracting the areas where the two are different. These areas represent abnormal areas within the outer boundary of the integrated land and sea elevation data where the elevation point data does not meet the relevant mapping requirements.

[0062] Furthermore, the abnormal region buffering process involves performing buffering on the abnormal regions obtained from the spatial analysis (intersection inversion) described above. The distance reference for the buffer is... (in (In accordance with the above formula (1), this is to offset the anomalies caused by the above land and sea integrated elevation data buffer processing, and to obtain the accurate range of the unrefined survey area;

[0063] Furthermore, by combining manual data collection methods by professional technicians and automatic acquisition methods by computers, the delineation of the unresolved survey area can be obtained. Users can choose the appropriate method according to their actual situation.

[0064] Step 104: Extract elevation data within a set distance outside the unrefined survey area as control data for known elevation points.

[0065] This step primarily involves extracting elevation point data from the periphery of the inaccurate survey area. Based on the inaccurate survey area defined in step 103, a vector surface for extracting elevation point data from the periphery of the inaccurate survey area is created. This vector surface is obtained by buffering the inaccurate survey area, with the buffer distance being no less than [amount missing]. (in (In accordance with the formula (1) above), users can adjust it according to the actual situation.

[0066] Furthermore, based on the elevation point data of the outer perimeter of the unrefined survey area, the land-sea integrated elevation data is extracted from the vector surface, thus completing the work of extracting the elevation point data of the outer perimeter of the unrefined survey area.

[0067] Step 105: Based on the extracted elevation point data within a set distance outside the unmeasured area, perform water depth interpolation on the unmeasured area using a quadratic thin plate spline function or a fourth-order response surface analysis function, and update the elevation point data of the unmeasured area based on the water depth interpolation results.

[0068] This step mainly involves interpolating elevation values ​​in areas where the measurements were not precise. Please refer to the appendix. Figure 4The flowchart for interpolating elevation values ​​in the unrefined survey area is as follows: Based on the aforementioned elevation point data from the periphery of the unrefined survey area, vector surfaces are extracted, and the elevation point data from the periphery of the unrefined survey area is used to complete the interpolation of elevation values ​​in the unrefined survey area. The required tasks include: counting the number N of vector surfaces extracted from the periphery elevation point data of the unrefined survey area; extracting vector surfaces i one by one from the periphery elevation point data of the unrefined survey area; extracting the relevant periphery elevation point data from the traversed vector surfaces i; and then completing the interpolation of elevation values ​​in the unrefined survey area using different interpolation methods. Specifically, the following two methods are used for spatial interpolation of land and sea integrated elevation data:

[0069] First, interpolation of land-sea integrated elevation data based on the response surface is performed within the vector surface range of elevation point data extraction outside the un-precision surveyed area. Refer to the following formula (2) for details. The interpolation interval shall not be less than (in To maintain consistency with the requirements represented by the above formula (1), users can make adjustments according to the actual situation.

[0070] Formula (2)

[0071] Note: In formula (2), represent In the equation, P represents the iteration order, indicating that the number of elevation points calculated based on the iteration order must not be less than this value; X represents the longitude value; and Y represents the latitude value. Represents coordinates The elevation value at that location is calculated using existing elevation data from the outer perimeter of the unrefined survey area. , , , , , , , , , Then, the response surface analysis function of the area is obtained, and the elevation value of any point can be obtained by substituting it into the location, thus completing the interpolation of the land and sea integrated elevation data.

[0072] Second, interpolation of land-sea integrated elevation data using thin-plate spline: Within the vector surface range of elevation point data extraction in the unmeasured area, interpolation of land-sea integrated elevation data is performed based on the thin-plate spline function. Refer to the following formulas (3) and (4) for details. The interpolation interval should not be less than [missing information]. (in To maintain consistency with the requirements represented by the above formula (1), users can make adjustments according to the actual situation.

[0073]

[0074] Formula (4)

[0075] Note: In formulas (3) and (4), The elevation value at point (X, Y) represents the elevation value. , , Represents the constant after the solution is obtained, in formula (3) In the corresponding formula (4) After solving the equation coefficients, the elevation value of any point can be obtained by substituting them into formula (4).

[0076] Furthermore, the interpolated elevation point data of the un-precisely surveyed area in the i-th region is obtained through the above spatial interpolation method. Then, this data is fused with the original data. The following steps are required: First, the original elevation point data is removed based on the vector surface of the elevation point data of the outer perimeter of the un-precisely surveyed area in the i-th region. Second, the interpolated elevation point data of the un-precisely surveyed area in the i-th region is mosaicked and fused to complete the processing of the elevation point data of the un-precisely surveyed area in the i-th region (or the data fusion operation can be performed after all un-precisely surveyed areas have been interpolated). The above work is repeated until all the elevation point data of the un-precisely surveyed areas are fused and updated, forming a unified land-sea integrated elevation data without un-precisely surveyed areas.

[0077] Step 106: Based on the merged and updated elevation point data, construct an irregular triangular network, and then create a land-sea integrated digital elevation model based on the irregular triangular network.

[0078] This step mainly involves constructing an integrated land-sea digital elevation model. Based on the integrated land-sea elevation data obtained in step 105, an irregular triangular network (TIN) is constructed. Then, according to actual needs, the grid size of the integrated land-sea digital elevation model is determined. After interpolation processing based on the TIN, the grid is transformed into raster data to obtain the integrated land-sea digital elevation model.

[0079] Example 2

[0080] See Figure 5 Based on the same inventive concept, embodiments of the present invention also provide a system for constructing an integrated land-sea digital elevation model for areas without precise surveying, comprising:

[0081] The data acquisition unit is used to perform the following steps:

[0082] A depth datum conversion model is established to convert ocean depth data into land elevation data based on the 1985 National Height Datum.

[0083] Acquire land topography data and ocean topography data, and perform multi-source heterogeneous data fusion operation on the land topography data and ocean topography data to generate integrated land and sea elevation data;

[0084] The data processing unit is used to perform the following steps:

[0085] The extent of the unmeasured area is determined based on the integrated land and sea elevation data.

[0086] Extract elevation data from points within a set distance outside the unmeasured area;

[0087] Based on the extracted elevation point data within a set distance outside the unmeasured area, the water depth of the unmeasured area is interpolated using a quadratic thin plate spline function or a fourth-order response surface analysis function. The elevation point data of the unmeasured area is then fused and updated based on the water depth interpolation results.

[0088] Based on the merged and updated elevation point data, an irregular triangular network is constructed, and a land-sea integrated digital elevation model is created based on the irregular triangular network.

[0089] Since this system corresponds to the method for constructing an integrated land-sea digital elevation model in the unrefined survey area according to the embodiments of the present invention, and the principle of solving the problem in this system is similar to that of this method, the implementation of this system can refer to the implementation process of the above method embodiments, and the repeated parts will not be described again.

[0090] Example 3

[0091] See Figure 6 Based on the same inventive concept, this embodiment of the invention also provides an electronic device, which includes a processor and a memory. The memory stores at least one instruction, at least one program, a code set, or an instruction set. The at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by the processor to realize the method for constructing an integrated land and sea digital elevation model for the unrefined survey area as described above.

[0092] It is understood that the memory may include random access memory (RAM) or read-only memory. Optionally, the memory may include non-transitory computer-readable storage medium. The memory can be used to store instructions, programs, code, code sets, or instruction sets. The memory may include a stored program area and a stored data area, wherein the stored program area may store instructions for implementing an operating system, instructions for at least one function, instructions for implementing the various method embodiments described above, etc.; the stored data area may store data created according to the use of the server, etc.

[0093] A processor may include one or more processing cores. The processor connects to various parts of the server via various interfaces and lines, performing various server functions and processing data by running or executing instructions, programs, code sets, or instruction sets stored in memory, and by accessing data stored in memory. Optionally, the processor may be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The processor may integrate one or more of a Central Processing Unit (CPU) and a modem. The CPU primarily handles the operating system and applications; the modem handles wireless communication. It is understood that the modem may also be implemented as a separate chip without being integrated into the processor.

[0094] Since this electronic device is the electronic device corresponding to the method for constructing an integrated land and sea digital elevation model in the unrefined survey area according to the embodiments of the present invention, and the principle of solving the problem by this electronic device is similar to that of this method, the implementation of this electronic device can refer to the implementation process of the above method embodiments, and the repeated parts will not be described again.

[0095] Example 4

[0096] Based on the same inventive concept, embodiments of the present invention also provide a computer-readable storage medium storing at least one instruction, at least one program, code set, or instruction set, wherein the at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by a processor to realize the method for constructing an integrated land-sea digital elevation model for an inaccurate survey area as described above.

[0097] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, including read-only memory (ROM), random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), one-time programmable read-only memory (OTPROM), electrically-Erasable Programmable Read-Only Memory (EEPROM), compactdisc read-only memory (CD-ROM) or other optical disc storage, disk storage, magnetic tape storage, or any other computer-readable medium capable of carrying or storing data.

[0098] Since the storage medium is the storage medium corresponding to the method for constructing an integrated land and sea digital elevation model in the unrefined survey area according to the embodiments of the present invention, and the principle of the storage medium in solving the problem is similar to that of the method, the implementation of the storage medium can refer to the implementation process of the above method embodiments, and the repeated parts will not be described again.

[0099] Example 5

[0100] In some possible implementations, various aspects of the methods of the embodiments of the present invention can also be implemented as a program product, comprising program code that, when run on a computer device, causes the computer device to perform the steps of the method for constructing an integrated land-sea digital elevation model in an unrefined survey area according to various exemplary embodiments of this application, as described above. The executable computer program code or "code" used to perform the various embodiments can be written in high-level programming languages ​​such as C, C++, C#, Smalltalk, Java, JavaScript, Visual Basic, Structured Query Language (e.g., Transact-SQL), Perl, or in various other programming languages.

[0101] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0102] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0103] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for constructing an integrated land-sea digital elevation model for an area with inaccurate survey data, characterized in that, include: A depth datum conversion model is established to convert ocean depth data into land elevation data based on the 1985 National Height Datum. Acquire land topography data and ocean topography data, and perform multi-source heterogeneous data fusion operation on the land topography data and ocean topography data to generate integrated land and sea elevation data; The scope of the un-precisely surveyed area is delineated based on the integrated land-sea elevation data, specifically including: buffering each point of the integrated land-sea elevation data; simultaneously obtaining the outer boundary of the integrated land-sea elevation data; merging the buffer processing results of the integrated land-sea elevation data to form the coverage area of ​​the integrated land-sea elevation data; combining the obtained outer boundary of the integrated land-sea elevation data and the coverage area of ​​the integrated land-sea elevation data, performing spatial analysis, which involves extracting the areas where the two differ. These areas represent abnormal regions within the outer boundary of the integrated land-sea elevation data where the elevation point data does not meet the relevant mapping requirements; based on the abnormal regions obtained from the above spatial analysis, buffer processing is performed; and the scope of the un-precisely surveyed area is delineated based on the buffer processing results. Extract elevation data from points within a set distance outside the unmeasured area; Based on the extracted elevation point data within a set distance outside the unmeasured area, the water depth of the unmeasured area is interpolated using a quadratic thin plate spline function or a fourth-order response surface analysis function. The elevation point data of the unmeasured area is then fused and updated based on the water depth interpolation results. Based on the merged and updated elevation point data, an irregular triangular network is constructed, and a land-sea integrated digital elevation model is created based on the irregular triangular network.

2. The method for constructing an integrated land-sea digital elevation model for unrefined survey areas according to claim 1, characterized in that, The multi-source heterogeneous data fusion operation specifically includes, in sequence: unifying the plane coordinate system and the elevation coordinate system, data structure conversion, attribute structure unification, and data merging.

3. The method for constructing an integrated land-sea digital elevation model for unrefined survey areas according to claim 1, characterized in that, The area of ​​the unmeasured zone is delineated according to the established formula (1), where the distance between two elevation points is... When the spacing is less than or equal to the required spacing of the mapping scale, the area is considered a normal area; when the distance between two elevation points... When the spacing exceeds the required interval of the mapping scale, this area is considered an area of ​​inaccurate surveying. Official (1) Represents the distance between two elevation points. For mapping scale.

4. The method for constructing an integrated land-sea digital elevation model for unrefined survey areas according to claim 1, characterized in that, Water depth interpolation operations specifically include: The vector surface is extracted, which is obtained by buffering the unmeasured area. The number of vector surfaces N extracted from the elevation point data of the periphery of the unrefined survey area is counted. Vector surfaces i are extracted one by one from the elevation point data of the periphery of the unrefined survey area. Based on the traversed vector surfaces i, the elevation point data of the periphery of the unrefined survey area involved are extracted. Then, the elevation values ​​of the unrefined survey area are interpolated using different interpolation methods. Among them, the different interpolation methods include response surface land-sea integrated elevation data interpolation and thin plate spline land-sea integrated elevation data interpolation. The interpolated elevation point data of the unmeasured area in the i-th region is obtained through the above spatial interpolation method. Then, the data is fused with the original data. The data fusion process includes: removing the original elevation point data based on the vector surface of the elevation point data of the outer perimeter of the unmeasured area in the i-th region; and updating the obtained interpolated elevation point data of the unmeasured area in the i-th region by mosaicking and fusion. Repeat the above process until all elevation point data in the unrefined survey areas are merged and updated, forming a unified land-sea integrated elevation data without unrefined survey areas.

5. A system for constructing an integrated land-sea digital elevation model for an area with inaccurate survey data, characterized in that: include: The data acquisition unit is used to perform the following steps: A depth datum conversion model is established to convert ocean depth data into land elevation data based on the 1985 National Height Datum. Acquire land topography data and ocean topography data, and perform multi-source heterogeneous data fusion operation on the land topography data and ocean topography data to generate integrated land and sea elevation data; The data processing unit is used to perform the following steps: The scope of the un-precisely surveyed area is delineated based on the integrated land-sea elevation data, specifically including: buffering each point of the integrated land-sea elevation data; simultaneously obtaining the outer boundary of the integrated land-sea elevation data; merging the buffer processing results of the integrated land-sea elevation data to form the coverage area of ​​the integrated land-sea elevation data; combining the obtained outer boundary of the integrated land-sea elevation data and the coverage area of ​​the integrated land-sea elevation data, performing spatial analysis, which involves extracting the areas where the two differ. These areas represent abnormal regions within the outer boundary of the integrated land-sea elevation data where the elevation point data does not meet the relevant mapping requirements; based on the abnormal regions obtained from the above spatial analysis, buffer processing is performed; and the scope of the un-precisely surveyed area is delineated based on the buffer processing results. Extract elevation data from points within a set distance outside the unmeasured area; Based on the extracted elevation point data within a set distance outside the unmeasured area, the water depth of the unmeasured area is interpolated using a quadratic thin plate spline function or a fourth-order response surface analysis function. The elevation point data of the unmeasured area is then fused and updated based on the water depth interpolation results. Based on the merged and updated elevation point data, an irregular triangular network is constructed, and a land-sea integrated digital elevation model is created based on the irregular triangular network.

6. An electronic device, characterized in that, The electronic device includes a processor and a memory. The memory stores at least one instruction, at least one program, a code set, or an instruction set. The at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by the processor to implement the method for constructing an integrated land-sea digital elevation model for unrefined survey areas as described in any one of claims 1 to 5.

7. A computer-readable storage medium, characterized in that, The storage medium stores at least one instruction, at least one program, code set, or instruction set, wherein the at least one instruction, the at least one program, the code set, or instruction set is loaded and executed by a processor to implement the method for constructing an integrated land-sea digital elevation model for unrefined survey areas as described in any one of claims 1 to 5.

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