A method and system for judging terrain change trends based on Cesium

Abstract

This invention relates to the field of terrain change detection technology, specifically to a method and system for judging terrain change trends based on Cesium. This invention intuitively loads the terrain oblique photography data of the target area into a target area model, allowing humans to visually identify areas of significant terrain change. Simultaneously, by utilizing target area models acquired at two different times, a terrain calculation plane is established for the terrain monitoring area to be judged. The difference in height between the two target area models relative to the terrain calculation plane can be used to determine whether there is terrain subsidence due to surface reduction and / or terrain uplift due to surface rise in the current terrain monitoring area. Therefore, terrain oblique photography data from different times can be selected as needed to determine whether terrain changes involve subsidence and / or uplift, thereby judging the terrain change trend. The operation is simple, the judgment results are highly reliable, the cost is low, and it meets practical detection needs.

Description

Technical Field

[0001] This invention relates to the field of terrain change detection technology, specifically to a method and system for judging terrain change trends based on Cesium. Background Technology

[0002] Sudden changes in terrain can cause huge losses to agricultural production and people's lives and property, and in some cases even devastating disasters. Therefore, it is necessary to effectively monitor changes in terrain so that people and property in areas with potential terrain changes can be evacuated in a timely manner to reduce losses and damage.

[0003] A landslide is a type of topographical change, referring to the natural phenomenon where soil or rock masses on a slope, influenced by factors such as river erosion, groundwater activity, rainwater soaking, earthquakes, and artificial slope cutting, slide downhill along a certain weak surface or zone under the influence of gravity, either as a whole or in parts. The moving rock (soil) mass is called a displaced body or sliding body, while the underlying rock (soil) mass that has not moved is called a sliding bed.

[0004] The most significant harms of landslides to rural areas are the destruction of farmland and houses, injury to people and livestock, damage to forests, roads, agricultural machinery and water conservancy facilities, and sometimes even devastating disasters. Landslides in towns often bury houses, injure or kill people and livestock, destroy fields, destroy factories, schools, government offices, and various facilities, causing power outages, water outages, and work stoppages, and sometimes even destroying entire towns. Landslides in industrial and mining areas can destroy mining facilities, injure or kill workers, destroy factory buildings, and force mines to shut down, often resulting in significant losses.

[0005] Currently, there are many methods for detecting landslide trends, such as regular human patrols and real-time monitoring by installing IoT sensors in designated areas. However, these methods have limited coverage areas, and considering factors such as actual economic costs and area size, sensors cannot be deployed over large areas. Alternatively, human patrols are too subjective, easily overlooked or misjudged, leading to inaccurate and untimely detection, failing to meet the time-sensitive detection requirements. Furthermore, human patrols pose a significant threat to the safety of patrol personnel. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for judging terrain change trends based on Cesium, thereby solving the problem of low testing efficiency of current multi-channel TR components.

[0007] The solution of the present invention to the above-mentioned technical problems is as follows:

[0008] A method for determining topographic change trends based on Cesium topography, characterized by the following steps:

[0009] S1. Collect and save the topographic oblique photography data of the target area according to the set collection frequency to obtain the topographic database of the target area. The topographic oblique photography data includes the collection time.

[0010] S2. Select two terrain oblique photography data from the target area terrain database and import them into Cesium. Use Cesium to obtain two target area models with different acquisition times, and stack the two target area models.

[0011] S3. Select the same terrain monitoring area on the two target area models to obtain the terrain calculation plane;

[0012] S4. Divide the terrain calculation plane into multiple grids, calculate the elevation between each grid and the two target area models, and determine the terrain change trend of the current terrain monitoring area based on the difference in elevation between each grid and the two target area models at the same location. If the terrain change is collapse and / or uplift, it is determined that the terrain of the current terrain monitoring area has a landslide trend; if the terrain change is stable, it is determined that the terrain of the current terrain monitoring area has a stable trend.

[0013] Further specifying, step S2 specifically includes the following steps:

[0014] S21. Based on the acquisition time, select two corresponding terrain oblique photography data from the target area terrain database, namely the first terrain oblique photography data and the second terrain oblique photography data. The acquisition time of the first terrain oblique photography data is earlier than the acquisition time of the second terrain oblique photography data.

[0015] S22. Import the selected first terrain oblique photography data and second shape oblique photography data into Cesium in sequence. Through Cesium, two overlapping first target area models and second target area models are obtained in the three-dimensional interface.

[0016] Further specifying, step S3 specifically includes the following steps:

[0017] S31. Confirm the terrain monitoring area on the first target area model or the second target area model;

[0018] S32. Establish n area points P located at the same plane height in the three-dimensional interface, so that all n area points P are located on the vertical line of the outer contour of the terrain monitoring area.

[0019] S33. Connect the n regional points P in sequence to form a terrain calculation plane.

[0020] Further specifying, step S4 specifically includes the following steps:

[0021] S41. Calculate the maximum horizontal length A based on the terrain. max The terrain calculation plane is divided into multiple parts at equal intervals along its length; based on the maximum horizontal width B of the terrain calculation plane... max The terrain calculation plane is divided into multiple parts at equal intervals along the width direction to complete the grid division of the terrain calculation plane, resulting in k grids, where k is a positive integer;

[0022] S42. Draw an extension line perpendicular to the terrain calculation plane along the center of each grid, and obtain the intersection points Z1~Z ... k And the intersection points Y1~Y1 of each extended line with the second target region model. k According to the intersection points Z1~Z k The elevation H1 to H2 of each grid relative to the first target region model is obtained by comparing the height difference with the corresponding grid center. k According to the intersection points Y1~Y k The elevation h1~h1 of each grid relative to the center of the corresponding grid is obtained from the height difference between the grid and the second target region model. k Let the elevation above the terrain calculation plane be represented by a positive number, and the elevation below the terrain calculation plane be represented by a negative number;

[0023] S43, according to ΔL i =h i -H i The terrain change ΔL corresponding to each grid was calculated. i Determine ΔL i If the value is negative, it indicates a landslide trend in the current terrain monitoring area; otherwise, it indicates a negative value. i If the value is 0, it indicates that the terrain change trend in the current terrain monitoring area is stable; otherwise, it indicates that there is a landslide trend in the current terrain monitoring area, where i = 1 to k.

[0024] Furthermore, the method for determining Cesium-based terrain change trends also includes:

[0025] S5. If it is determined that there is a landslide trend in the current terrain monitoring area, the collapse volume and / or uplift volume of the current terrain monitoring area are calculated based on the area of ​​each grid and the difference in elevation between each grid and the two target area models.

[0026] Further specifying, step S5 specifically includes the following steps:

[0027] S51. If it is determined that there is a landslide trend in the current terrain monitoring area, calculate the area of ​​the grid with terrain change.

[0028] S52. Divide each topographic change into a subsidence group according to positive values ​​and a uplift group according to negative values;

[0029] S53. Calculate the product of the absolute value of the terrain change corresponding to each grid in the collapse group and the area of ​​the corresponding grid to obtain the individual collapse volume. Add up all the individual collapse volumes to obtain the collapse volume of the current terrain monitoring area.

[0030] Calculate the product of the terrain change corresponding to each grid in the uplift group and the area of ​​the corresponding grid to obtain the volume of a single uplift. Add up all the obtained individual uplift volumes to obtain the uplift volume of the current terrain monitoring area.

[0031] A system for determining terrain change trends based on Cesium, characterized in that it includes:

[0032] The terrain oblique photography data acquisition unit is used to acquire and save the terrain oblique photography data of the target area according to the set acquisition frequency, so as to obtain the terrain database of the target area. The terrain oblique photography data includes the acquisition time.

[0033] The target area model building unit is used to select two terrain oblique photography data from the target area terrain database and import them into Cesium. Through Cesium, two target area models with different acquisition times are obtained, and the two target area models are stacked.

[0034] The terrain calculation plane creation unit is used to select the same terrain monitoring area on two target area models to obtain the terrain calculation plane;

[0035] The terrain change trend judgment unit is used to divide the terrain calculation plane into multiple grids, calculate the elevation between each grid and the two target area models, and judge the terrain change trend of the current terrain monitoring area based on the difference in elevation between each grid and the two target area models at the same position. If the terrain change is collapse and / or uplift, the corresponding terrain collapse signal and / or terrain uplift signal are output, and the difference in elevation between each grid and the two target area models at the same position is sent to the terrain change calculation unit. If the terrain change is stable, the terrain stability signal is output.

[0036] The terrain change calculation unit is used to calculate the collapse volume and / or uplift volume of the current terrain monitoring area based on the area of ​​each grid and the difference in elevation between each grid and the two target area models.

[0037] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the above-described method when executing the computer program.

[0038] A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, which, when executed by a processor, implements the above-described method.

[0039] A computer program product, characterized in that the computer program product includes a computer program, which, when executed by a processor, implements the method described above.

[0040] The beneficial effects of this invention are as follows:

[0041] 1. This invention is based on the open-source Cesium and combines it with a topographic oblique photography data acquisition method. It can intuitively load the topographic oblique photography data of the target area into a target area model, allowing people to visually identify areas with significant terrain changes. At the same time, by using the target area models acquired at two different times, a terrain calculation plane is established for the terrain monitoring area to be judged. The difference in height between the two target area models relative to the terrain calculation plane can be used to determine whether there is terrain subsidence caused by surface reduction and / or terrain uplift caused by surface rise in the current terrain monitoring area. Thus, it is possible to select topographic oblique photography data from different times as needed to determine whether there is subsidence and / or uplift in terrain changes, thereby judging the trend of terrain change. The operation is simple, the judgment results are highly reliable, the cost is low, and it meets the actual detection needs.

[0042] 2. This invention can also calculate the change in terrain, i.e., the collapse volume and / or uplift volume, between two data collections when a landslide trend exists in the terrain monitoring area. This allows for early or timely warnings when the terrain change is small. It can also increase the frequency of image collection in the target area to achieve more frequent and detailed detection of terrain changes, further improving the accuracy and reliability of the judgment of terrain change trends. In addition, it can also be used to calculate the volume of earthwork and collapse generated by landslides after landslides, thereby enabling more accurate and efficient subsequent processing and accelerating the reconstruction of landslide-affected areas. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the process for determining the terrain change trend based on Cesium in Embodiment 1 of the present invention;

[0044] Figure 2 An interface map is determined for the terrain monitoring area of ​​this invention; Figure 2 a is a top view of the terrain monitoring area. Figure 2 b is an isometric map of the terrain monitoring area;

[0045] Figure 3 This is a schematic diagram of the terrain calculation plane of the present invention, wherein... Figure 3 a is a schematic diagram of the terrain calculation plane. Figure 3 b is a schematic diagram showing the maximum length and maximum width of the terrain calculation plane; Figure 3 c is a schematic diagram of the planar grid division for terrain calculation;

[0046] Figure 4 This is a schematic diagram illustrating the calculation of the grid and corresponding terrain region model elevation in this invention;

[0047] Figure 5 This is a schematic diagram of the judgment process based on Cesium terrain change trend in Embodiment 2 of the present invention;

[0048] Figure 6 This is a schematic diagram of the Cesium-based terrain change trend judgment system in Embodiment 3 of the present invention. Detailed Implementation

[0049] Example 1

[0050] refer to Figure 1 This embodiment provides a method for determining the trend of terrain change based on Cesium, including the following steps:

[0051] S1. Collect and save the topographic oblique photography data of the target area according to the set collection frequency to obtain the topographic database of the target area. The topographic oblique photography data includes the collection time.

[0052] Specifically, drones or satellites can typically be used to collect images of a certain area, obtaining topographic oblique photography data of that area. This topographic oblique photography data includes the acquisition time and three-dimensional data of the target area.

[0053] Topographic oblique photography data of the target area can be collected at set times, such as once a week, or once an hour when needed. The collection frequency can be adjusted as needed, and the collection area can also be adjusted according to the detection requirements. When judging the trend of terrain change, at least two sets of topographic oblique photography data collected at different times are required. The topographic oblique photography data collected each time is saved to form a topographic database of the target area, so that the terrain changes of the target area or a certain area of ​​the target area can be manually compared over a large time range later.

[0054] S2. Select two terrain oblique photography data from the target area terrain database and import them into Cesium. Use Cesium to obtain two target area models with different acquisition times, and stack the two target area models.

[0055] S3. Select the same terrain monitoring area on the two target area models to obtain the terrain calculation plane;

[0056] S4. Divide the terrain calculation plane into multiple grids, calculate the elevation between each grid and the two target area models, and determine the terrain change trend of the current terrain monitoring area based on the difference in elevation between each grid and the two target area models at the same location. If the terrain change is collapse and / or uplift, it is determined that the terrain of the current terrain monitoring area has a landslide trend; if the terrain change is stable, it is determined that the terrain of the current terrain monitoring area has a stable trend.

[0057] Step S2 specifically includes the following steps:

[0058] S21. Based on the acquisition time, select two corresponding terrain oblique photography data from the target area terrain database, namely the first terrain oblique photography data and the second terrain oblique photography data. The acquisition time of the first terrain oblique photography data is earlier than the acquisition time of the second terrain oblique photography data.

[0059] The data collection time can be selected according to needs. For example, if timely updates to the terrain of a target area or a specific area within a target area are required, the latest topographic oblique photography data can be selected from the target area's terrain database each time. Alternatively, if it is necessary to determine the terrain change trend of a target area or a specific area within a target area, the two most recent topographic oblique photography data can be selected initially. Then, when determining the terrain trend change in the second assessment, the later topographic oblique photography data can be discarded, and the latest topographic oblique photography data can be selected. At this point, the terrain change trend between the two collection time intervals can be determined. By repeating this process, even when there are minor terrain changes at each collection time, the latest topographic oblique photography data can be compared with the earliest topographic oblique photography data, thereby enabling timely detection of terrain change trends, timely and effective disaster early warning, and ensuring accurate and reliable judgments.

[0060] It is also possible to select topographic oblique photography data from any two acquisition time points as needed to compare the degree of topographic change or development changes before and after a disaster.

[0061] To facilitate the differentiation between the two topographic oblique photography data, the two selected topographic oblique photography data are distinguished by the first topographic oblique photography data and the second topographic oblique photography data. The first topographic oblique photography data was acquired earlier than the second topographic oblique photography data. The distinction between the first and second topographic oblique photography data is only for any two selected topographic oblique photography data and does not refer to the order of topographic oblique photography data in the target area topographic database.

[0062] S22. Import the selected first terrain oblique photography data and second shape oblique photography data into Cesium in sequence. Through Cesium, two overlapping first target area models and second target area models are obtained in the three-dimensional interface.

[0063] The selected first topographic oblique photography data and second topographic oblique photography data can be imported into Cesium in sequence.

[0064] The first topographic oblique photographic data and the second shape oblique photographic data imported into Cesium are displayed in the form of a 3D model in the 3D interface of Cesium. The first topographic oblique photographic data is loaded by Cesium to obtain the first target area model, and the second shape oblique photographic data is loaded by Cesium to obtain the second target area model.

[0065] Since most of the terrain in the target area is usually stable, the first and second terrain oblique photographic data are mostly the same in 3D. The two target area models loaded will also have a large degree of overlap. Therefore, the first and second target area models are displayed in a stacked manner in the 3D interface. To facilitate the calculation of terrain changes, the first imported terrain oblique photographic data can be used as the first terrain oblique photographic data, and the subsequently imported terrain oblique photographic data can be used as the second terrain oblique photographic data. This is usually used to calculate the amount of change rather than to determine the trend of change. Typically, the terrain oblique photographic data collected earlier is used as the first terrain oblique photographic data, and the terrain oblique photographic data collected later is used as the second terrain oblique photographic data, so that the terrain change trend of the second terrain oblique photographic data compared with the first terrain oblique photographic data can be determined.

[0066] refer to Figure 2 Step S3 specifically includes the following steps:

[0067] S31. Confirm the terrain monitoring area on the first target area model or the second target area model;

[0068] Since the first and second target area models cover a wide area and have many overlapping areas, the computational load increases and the practical significance is small. Therefore, depending on the specific needs, the areas that need to be judged in the first or second target area model are usually circled as the terrain monitoring area. Subsequently, only the terrain change trend within the terrain monitoring area will be judged, thereby reducing the computational load, reducing the computation time, and improving the effectiveness of the judgment.

[0069] Therefore, the location of the terrain monitoring area on the first target area model or the second target area model can be determined first, based on the requirements.

[0070] S32. Establish n area points P located at the same plane height in the three-dimensional interface, so that all n area points P are located on the vertical line of the outer contour of the terrain monitoring area.

[0071] refer to Figure 2 a and Figure 2 b, where n area points P of equal height can be established at the edge of the defined terrain monitoring area. At this time, each area point P is scattered at the edge of the terrain monitoring area. As needed, the position of any area point P in the horizontal direction can be dragged to change the shape, size and / or position of the terrain monitoring area formed by the n area points P, thereby meeting the actual use requirements.

[0072] When establishing n region points with the same height, the height of each region point P can be arbitrarily selected. After all n region points are established, the height can be adjusted according to the height of any region point to make the height of each region point P the same, or the height of the first region point can be used as a reference and the height of the remaining region points can be the same as the height of the first region point.

[0073] The height of the first area point can be adjusted by changing the viewpoint of the 3D interface, allowing the first area point to move along the Z-axis perpendicular to the ground surface, thereby achieving height adjustment of the area point.

[0074] S33. Connect the n regional points P in sequence to form a terrain calculation plane.

[0075] refer to Figure 3 a, whereby by connecting the established regional points P1 to P13 in sequence, a contour of the terrain calculation plane is formed that is vertically aligned with the contour of the terrain monitoring area. The area surrounded by the contour of the terrain calculation plane is taken as the terrain calculation plane. The terrain calculation plane is parallel to the horizontal plane. After obtaining the terrain calculation plane, the height of the terrain calculation plane can be adjusted. Therefore, the terrain calculation plane can intersect with and / or not intersect with the first target area model and / or the second target area model.

[0076] Step S4 specifically includes the following steps:

[0077] S41. Calculate the maximum horizontal length A based on the terrain. max The terrain calculation plane is divided into multiple parts at equal intervals along its length; based on the maximum horizontal width B of the terrain calculation plane... max The terrain calculation plane is divided into multiple parts at equal intervals along the width direction to complete the grid division of the terrain calculation plane, resulting in k grids, where k is a positive integer;

[0078] refer to Figure 3 b and Figure 3c. Since the surfaces of the first and second target region models are usually uneven, the height difference between them cannot be directly calculated. Usually, the terrain calculation plane is divided into multiple grids. The more grids there are, the more accurate the calculation results will be, but the more computational load will be generated. For example, the terrain calculation plane is divided into 100α parts at equal intervals along the length direction and 100α parts at equal intervals along the width direction. Therefore, the size of the grid obtained by the grid division can be selected by the division precision α. ​​The larger the division precision α, the more accurate the final judgment result will be. In order to meet the needs of a wide range of applications, the minimum precision of the division is set to 1. At the same time, in order to ensure the accuracy and reliability of the judgment, the grid is divided according to the maximum length and maximum width of the terrain calculation plane in the horizontal direction.

[0079] Calculate the maximum horizontal length A based on the terrain. max The terrain calculation plane is divided into 100α equal parts along its length; the maximum horizontal width B of the terrain calculation plane is determined. max The terrain calculation plane is divided into 100α parts at equal intervals along the width direction to complete the grid division of the terrain calculation plane, resulting in k grids. The k grids refer to the grids located in the terrain calculation plane. Since the terrain calculation plane usually has angles that are not equal to 90°, the size of each grid is not entirely the same.

[0080] Furthermore, since the maximum length and maximum width of each terrain calculation plane may not be equal, the length and width of grids of the same size may not be equal.

[0081] S42. Draw an extension line perpendicular to the terrain calculation plane along the center of each grid, and obtain the intersection points Z1~Z ... k And the intersection points Y1~Y1 of each extended line with the second target region model. k According to the intersection points Z1~Z k The elevation H1 to H2 of each grid relative to the first target region model is obtained by comparing the height difference with the corresponding grid center. k According to the intersection points Y1~Y k The elevation h1~h1 of each grid relative to the center of the corresponding grid is obtained from the height difference between the grid and the second target region model. k Let the elevation above the terrain calculation plane be represented by a positive number, and the elevation below the terrain calculation plane be represented by a negative number;

[0082] refer to Figure 4Each grid is a triangle, rectangle, or pentagon. Each triangle or pentagon is treated as a quadrilateral with the same area for calculation. The center of each grid is selected, and an extension line is drawn through the center of each grid using Cesium. The extension line of each grid center is perpendicular to the terrain calculation plane. The extension line of each grid center extends in two directions along the center of the corresponding grid: upward and downward along the terrain calculation plane.

[0083] At this point, the extension line of each grid center, whether on or below the terrain calculation plane, will intersect with the first target region model and the second target region model respectively, resulting in the intersection points Z1~Z2 of the extension line of each grid with the first target region model. k The intersection points Y1~Y2 of the extension line of each grid and the second target region model are obtained. k Intersection points Z1~Z k All of these are points corresponding to the first target region model, with intersection points Y1 to Y2. k These are all points corresponding to the second target region model, thus allowing us to obtain the intersection points Z1 to Z2. k Intersection points Y1~Y k By calculating the vertical height value and the horizontal height value based on the terrain, the elevation H1~H1000 between each grid center and the first target area model can be obtained. k The elevations h1 to h2 of each grid center relative to the second target region model are obtained. k .

[0084] To facilitate the calculation of terrain changes between two target region models at the same location, the elevations of the first and second target region models located above the terrain calculation plane and their corresponding grid centers are represented by positive values. The elevations of the first and second target region models located below the terrain calculation plane and their corresponding grid centers are represented by negative values. That is, the terrain calculation plane is the horizontal axis, values ​​below the axis are negative, and values ​​above the axis are positive. The positive and negative values ​​are only used to indicate the position relative to the terrain calculation plane. When the elevation is within the terrain calculation plane, the elevation is 0, and the positive and negative values ​​are not distinguished.

[0085] S43, according to ΔL i =h i -H i The terrain change ΔL corresponding to each grid was calculated. i Determine ΔL i If the value is negative, it indicates a landslide trend in the current terrain monitoring area; otherwise, it indicates a negative value. iIf the value is 0, then the current terrain monitoring area is considered to be in a stable trend; otherwise, the current terrain monitoring area is considered to be in a landslide trend, where i = 1 to k.

[0086] Among them, the elevation h of the i-th grid and the second target region model is used. i The elevation H of the i-th grid and the first target region model i By subtracting the values, we obtain the height difference ΔL between the second target region model and the first target region model in the vertical direction at the i-th grid center. i The elevation difference can be used to determine the topographic changes between the second target area model and the first target area model in that numerical direction. If the elevation difference is negative, it means that the second target area model is lower than the first target area model at the same location, which means that the surface at that location has dropped and there may be a risk of collapse. The topographic changes in this area show a tendency to landslide. If the elevation difference is 0, it means that the elevation has not changed, so the topographic changes in this area are stable. If the elevation difference is positive, it means that the elevation in this area has increased and the topography has risen. The topography in this area also shows a tendency to landslide.

[0087] Therefore, determine ΔL i If the value is negative, it indicates a landslide trend in the current terrain monitoring area; otherwise, it indicates a negative value. i If the value is 0, it indicates that the current terrain monitoring area is in a stable trend; otherwise, it indicates that the terrain monitoring area is in a landslide trend. Here, i represents the i-th grid among k grids.

[0088] Example 2

[0089] refer to Figure 5 Based on Embodiment 1, but differing from Embodiment 1, this embodiment provides a method for determining Cesium-based terrain change trends that further includes the following steps:

[0090] S5. If it is determined that there is a landslide trend in the current terrain monitoring area, the collapse volume and / or uplift volume of the current terrain monitoring area are calculated based on the area of ​​each grid and the difference in elevation between each grid and the two target area models.

[0091] Step S5 specifically includes the following steps:

[0092] S51. If it is determined that there is a landslide trend in the current terrain monitoring area, calculate the area of ​​the grid with terrain change.

[0093] S52. Divide each topographic change into a subsidence group according to positive values ​​and a uplift group according to negative values;

[0094] S53. Calculate the product of the absolute value of the terrain change corresponding to each grid in the collapse group and the area of ​​the corresponding grid to obtain the individual collapse volume. Add up all the individual collapse volumes to obtain the collapse volume of the current terrain monitoring area.

[0095] Calculate the product of the terrain change corresponding to each grid in the uplift group and the area of ​​the corresponding grid to obtain the volume of a single uplift. Add up all the obtained individual uplift volumes to obtain the uplift volume of the current terrain monitoring area.

[0096] When it is found that there is a landslide trend in the current terrain monitoring area, the current collapse volume and uplift volume can be further calculated. Due to geological changes, there may be a situation where there is an uplift volume but no collapse volume, and there may also be a situation where there is a collapse volume but no uplift volume. Moreover, when the uplift volume and collapse volume exist at the same time, there may also be a situation where the two are not equal.

[0097] When calculating the volume of a bulge or a collapse, the volume of the bulge or collapse on the current grid can be calculated by using the area of ​​the grid with terrain changes and the corresponding terrain changes.

[0098] To calculate the total subsidence and uplift volumes of the current terrain monitoring area, we need to collect all terrain changes with positive values ​​to form an uplift group and all terrain changes with negative values ​​to form a subsidence group. The total uplift volume is obtained by adding the product of the area of ​​each grid in the uplift group and the corresponding terrain change. Similarly, the total subsidence volume is obtained by adding the product of the area of ​​each grid in the subsidence group and the corresponding terrain change. Thus, we obtain the subsidence and uplift volumes of the current terrain monitoring area.

[0099] Because there are situations where errors can be offset when calculating the collapse and uplift volumes, the actual calculated topographic changes are chosen when calculating topographic changes; that is, when 0 ≤ |ΔL| i When |≤l, ΔL i =ΔL i Meanwhile, the calculated collapse group value is negative, and the collapse volume is taken as its absolute value.

[0100] Example 3

[0101] refer to Figure 6 Based on the methods described in Examples 1 and 2, this embodiment provides a system for determining Cesium-based terrain change trends, including:

[0102] The terrain oblique photography data acquisition unit is used to acquire and save the terrain oblique photography data of the target area according to the set acquisition frequency, so as to obtain the terrain database of the target area. The terrain oblique photography data includes the acquisition time.

[0103] The target area model building unit is used to select two terrain oblique photography data from the target area terrain database and import them into Cesium. Through Cesium, two target area models with different acquisition times are obtained, and the two target area models are stacked.

[0104] The terrain calculation plane creation unit is used to select the same terrain monitoring area on two target area models to obtain the terrain calculation plane;

[0105] The terrain change trend judgment unit is used to divide the terrain calculation plane into multiple grids, calculate the elevation between each grid and the two target area models, and judge the terrain change trend of the current terrain monitoring area based on the difference in elevation between each grid and the two target area models at the same position. If the terrain change is collapse and / or uplift, the corresponding terrain collapse signal and / or terrain uplift signal are output, and the difference in elevation between each grid and the two target area models at the same position is sent to the terrain change calculation unit. If the terrain change is stable, the terrain stability signal is output.

[0106] The terrain change calculation unit is used to calculate the collapse volume and / or uplift volume of the current terrain monitoring area based on the area of ​​each grid and the difference in elevation between each grid and the two target area models.

[0107] This embodiment also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the methods described in Embodiment 1 and / or Embodiment 2.

[0108] This embodiment also provides a computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, which, when executed by a processor, implements the methods described in Embodiment 1 and / or Embodiment 2.

[0109] This embodiment also provides a computer program product, characterized in that the computer program product includes a computer program, which, when executed by a processor, implements the methods described in Embodiment 1 and / or Embodiment 2.

Claims

1. A method for determining the trend of terrain change based on Cesium, characterized in that, Includes the following steps: S1. Collect and save the topographic oblique photography data of the target area according to the set collection frequency to obtain the topographic database of the target area. The topographic oblique photography data includes the collection time. S2. Select two terrain oblique photography data from the target area terrain database and import them into Cesium. Use Cesium to obtain two target area models with different acquisition times, and stack the two target area models. S3. Select the same terrain monitoring area on the two target area models to obtain the terrain calculation plane; Step S3 specifically includes the following steps: S31. Confirm the terrain monitoring area on the first target area model or the second target area model; S32. Establish n area points P located at the same plane height in the three-dimensional interface, so that all n area points P are located on the vertical line of the outer contour of the terrain monitoring area. S33. Connect the n regional points P in sequence to form a terrain calculation plane; S4. Divide the terrain calculation plane into multiple grids, calculate the elevation between each grid and the two target area models, and determine the terrain change trend of the current terrain monitoring area based on the difference in elevation between each grid and the two target area models at the same location. If the terrain change is collapse and / or uplift, it is determined that the terrain of the current terrain monitoring area has a landslide trend; if the terrain change is stable, it is determined that the terrain of the current terrain monitoring area has a stable trend. Step S4 specifically includes the following steps: S41. Calculate the maximum horizontal length A based on the terrain. max The terrain calculation plane is divided into multiple parts at equal intervals along its length; based on the maximum horizontal width B of the terrain calculation plane... max The terrain calculation plane is divided into multiple parts at equal intervals along the width direction to complete the grid division of the terrain calculation plane, resulting in k grids, where k is a positive integer; S42. Draw an extension line perpendicular to the terrain calculation plane along the center of each grid, and obtain the intersection points Z1~Z1~Z2 of each extension line with the first target area model. k And the intersection points Y1~Y1 of each extended line with the second target region model. k According to the intersection points Z1~Z k The elevation H1~H of each grid relative to the first target region model is obtained by comparing the height difference with the corresponding grid center. k According to the intersection points Y1~Y k The elevation h1~h of each grid relative to the center of the corresponding grid is obtained from the height difference between the grid and the second target region model. k Let the elevation above the terrain calculation plane be represented by a positive number, and the elevation below the terrain calculation plane be represented by a negative number; S43, according to ΔL i =h i -H i The terrain change ΔL corresponding to each grid was calculated. i Determine ΔL i If the value is negative, it indicates a landslide trend in the current terrain monitoring area; otherwise, it indicates a negative value. i If the value is 0, it indicates that the terrain change trend in the current terrain monitoring area is stable; otherwise, it indicates that the terrain in the current terrain monitoring area has a landslide trend, where i = 1~k.

2. The method for determining the trend of terrain change based on Cesium as described in claim 1, characterized in that, Step S2 specifically includes the following steps: S21. Based on the acquisition time, select two corresponding terrain oblique photography data from the target area terrain database, namely the first terrain oblique photography data and the second terrain oblique photography data. The acquisition time of the first terrain oblique photography data is earlier than the acquisition time of the second terrain oblique photography data. S22. Import the selected first terrain oblique photography data and second shape oblique photography data into Cesium in sequence. Through Cesium, two overlapping first target area models and second target area models are obtained in the three-dimensional interface.

3. The method for determining the trend of terrain change based on Cesium as described in claim 1, characterized in that, The method for determining Cesium-based terrain change trends also includes: S5. If it is determined that there is a landslide trend in the current terrain monitoring area, the collapse volume and / or uplift volume of the current terrain monitoring area are calculated based on the area of ​​each grid and the difference in elevation between each grid and the two target area models.

4. The method for determining the trend of terrain change based on Cesium as described in claim 3, characterized in that, Step S5 specifically includes the following steps: S51. If it is determined that there is a landslide trend in the current terrain monitoring area, calculate the area of ​​the grid with terrain changes. S52. Divide each topographic change into a subsidence group according to positive values ​​and a uplift group according to negative values; S53. Calculate the product of the absolute value of the terrain change corresponding to each grid in the collapse group and the area of ​​the corresponding grid to obtain the individual collapse volume. Add up all the individual collapse volumes to obtain the collapse volume of the current terrain monitoring area. Calculate the product of the terrain change corresponding to each grid in the uplift group and the area of ​​the corresponding grid to obtain the volume of a single uplift. Add up all the obtained individual uplift volumes to obtain the uplift volume of the current terrain monitoring area.

5. A system for determining the trend of terrain change based on Cesium, characterized in that, include: The terrain oblique photography data acquisition unit is used to acquire and save the terrain oblique photography data of the target area according to the set acquisition frequency, so as to obtain the terrain database of the target area. The terrain oblique photography data includes the acquisition time. The target area model building unit is used to select two terrain oblique photography data from the target area terrain database and import them into Cesium. Through Cesium, two target area models with different acquisition times are obtained, and the two target area models are stacked. The terrain calculation plane creation unit is used to select the same terrain monitoring area on two target area models to obtain the terrain calculation plane; The terrain change trend judgment unit is used to divide the terrain calculation plane into multiple grids, calculate the elevation between each grid and the two target area models, and judge the terrain change trend of the current terrain monitoring area based on the difference in elevation between each grid and the two target area models at the same position. If the terrain change is collapse and / or uplift, the corresponding terrain collapse signal and / or terrain uplift signal are output, and the difference in elevation between each grid and the two target area models at the same position is sent to the terrain change calculation unit. If the terrain change is stable, the terrain stability signal is output. The terrain change calculation unit is used to calculate the collapse volume and / or uplift volume of the current terrain monitoring area based on the area of ​​each grid and the difference in elevation between each grid and the two target area models.

6. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method according to any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method according to any one of claims 1 to 4.

8. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the method according to any one of claims 1 to 4.

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