A topographic survey system for territorial spatial planning

Abstract

The present invention discloses a topographic survey system for territorial spatial planning, which relates to the technical field of topographic survey. It includes an acquisition area division module for collecting historical topographic maps of the area to be measured, calculating the topographic complexity of each topographic survey sub-area, and determining the measurement method for each topographic survey sub-area; a measurement environment analysis module for collecting environmental data of the topographic survey sub-area during the time when lidar collects data, calculating the environmental error coefficient, and issuing an environmental error warning; a data acquisition module using a drone equipped with lidar to measure the topographic data of the topographic survey sub-area, marking the fine measurement area, and performing two measurements of the topographic data to form complete point cloud data; a topographic data analysis module for generating a measurement topographic map, comparing the initial topographic map with the measurement topographic map, identifying the different parts, and outputting them as the changed areas of the territorial spatial planning. It can accurately identify the changes in the terrain and can more reasonably adjust and optimize the planning layout.

Description

Technical Field

[0001] The present invention relates to the technical field of topographic surveying, and particularly to a topographic surveying system for territorial space planning. Background Art

[0002] Currently, topographic surveying mainly relies on a variety of technical means, including traditional geodetic surveying, aerial photogrammetry, remote sensing technology surveying, and GPS / CORS systems, etc. These methods have their own advantages and disadvantages, but all have certain limitations in practical applications. For example, although the traditional geodetic surveying method has high accuracy, its operation cycle is long and the labor intensity is high; although aerial photogrammetry has high efficiency and a wide coverage range, it has high requirements for flight conditions and post-processing technologies; remote sensing technology surveying is greatly affected by weather and ground cover; while the GPS / CORS system can overcome adverse factors such as terrain and climate, it may still be interfered in certain specific regions and environments. How to improve the surveying efficiency while ensuring the surveying accuracy is a major challenge faced by current topographic surveying. Especially in large-scale territorial space planning projects, how to quickly and accurately obtain topographic data has become a key factor restricting the project progress.

[0003] In the Chinese invention application with the application publication number CN118548821A, a high-precision measurement method for continuous changes in surface micro-topography is disclosed, which includes first making a rectangular frame with targets pasted around it, regarding the lower left corner of the frame as the coordinate origin, and sequentially obtaining the coordinates of each target; according to the size of the rectangular frame in the area to be measured, inserting 4 fixed piles into the ground, placing the frame on the fixed piles, and leveling the frame with a level; using a smartphone to take photos perpendicular to the frame from front to back, and the overlap degree of adjacent two photos needs to be greater than 70%; importing the taken photos and target coordinates into image processing software, setting the targets, aligning the photos, generating point clouds, and then generating DEM; after taking the photos, removing the rectangular frame and keeping the fixed piles in the ground, and repeating the above operations at different time nodes according to the test purpose.

[0004] In the above invention application, by adjusting the size of the rectangular frame, the high-stem vegetation and the micro-topography under the forest are measured, and through software modeling, a high-precision point cloud model and DEM of the area to be measured can be obtained, so as to monitor the continuous changes in the surface micro-topography of the area to be measured. However, the acquisition method is complex and requires continuous and uninterrupted measurement of topographic data. But the topographic data often changes little in a short period of time. Continuously collecting and processing these data will cause waste of resources, and the acquisition and processing of point cloud data are easily interfered by environmental factors. Insufficient data accuracy may lead to the lack of sufficient basis for decision-makers when formulating relevant policies and plans, affecting the scientificity and rationality of decisions.

[0005] Therefore, the present invention provides a topographic surveying system for territorial space planning. Summary of the Invention

[0006] (1) Technical problems to be solved

[0007] In view of the deficiencies of the prior art, the present invention provides a topographic survey system for territorial space planning. The present invention divides the measurement area into individual sub-areas according to topographic units, and clarifies the measurement methods for each sub-area. For different topographic units, more suitable measurement methods and accuracy requirements can be adopted, thereby improving the overall measurement accuracy. Collect environmental data of the topographic survey sub-areas during the data collection time of lidar, calculate the environmental error coefficient, issue an environmental error warning, and identify in advance the risk of measurement errors that may be caused by environmental factors to avoid data distortion. Mark the fine measurement areas and conduct two topographic data measurements to further improve the data accuracy of these areas, which helps to ensure the accuracy and reliability of the entire topographic data set. Compare the initial topographic map with the complete topographic map, identify the different parts, and output them as the changed areas of territorial space planning. The changes in natural elements such as terrain, landform, and vegetation cover can be accurately identified, and the planning layout can be adjusted and optimized more reasonably, thus solving the technical problems described in the background art.

[0008] (2) Technical solutions

[0009] To achieve the above objectives, the present invention is realized through the following technical solutions: A topographic survey system for territorial space planning, comprising:

[0010] An acquisition area division module, configured to collect historical topographic maps of the area to be measured, evenly divide the area to be measured into individual topographic survey sub-areas with equal areas according to the historical topographic maps, calculate the topographic complexity of each topographic survey sub-area, and determine the measurement method for each topographic survey sub-area;

[0011] A measurement environment analysis module, configured to collect environmental data of the topographic survey sub-areas during the data collection time of lidar, calculate the environmental error coefficient, and issue an environmental error warning;

[0012] A data acquisition module, using a drone equipped with lidar to measure the topographic data of the topographic survey sub-areas, construct a first point cloud database, project the three-dimensional point cloud data in the first point cloud database onto a two-dimensional plane, divide the two-dimensional plane into evenly sized point cloud grids with an area of 1 square meter, calculate the complexity of each point cloud grid , mark the fine measurement areas, conduct two topographic data measurements, analyze and form second point cloud data, and fuse the second point cloud data into the first point cloud database according to GPS coordinates to form complete point cloud data;

[0013] A topographic data analysis module, configured to generate a measurement topographic map based on the complete point cloud data, compare the initial topographic map with the measurement topographic map, identify the different parts, and output them as the changed areas of territorial space planning.

[0014] Further, obtain the historical topographic map of the area to be measured as the initial topographic map by accessing online platforms and databases such as the National Geospatial Data Cloud and Tianditu. Use GIS software (such as ArcGIS, QGIS, etc.) or programming tools (such as Python combined with the GeoPandas library) to divide the initial topographic map into grids of equal size. Each grid is a topographic measurement sub-region and is sequentially numbered.

[0015] Further, use GIS software to extract the number of contour lines and the elevation values of each contour line in the topographic measurement sub-region, and calculate the initial topographic complexity of each topographic measurement sub-region :

[0016]

[0017] where, a represents the sequential number of each topographic measurement sub-region, represents the maximum value of the contour line elevation values within the same topographic measurement sub-region, represents the minimum value of the contour line elevation values within the same topographic measurement sub-region.

[0018] Further, sort the topographic measurement sub-regions from largest to smallest according to the size of the initial topographic complexity . Mark the top 30% of the sorted topographic measurement sub-regions as complex terrain regions, and set the lidar to a high sampling frequency for data acquisition. Mark the last 30% of the sorted topographic measurement sub-regions as simple terrain regions, and set the lidar to a low sampling frequency for data acquisition. Mark the remaining topographic measurement sub-regions as regular terrain regions, and set the lidar to a regular sampling frequency for data acquisition.

[0019] Further, randomly set several detection points within the topographic measurement sub-region. Use a light intensity meter to detect the light intensity of each detection point, a humidity sensor to detect the humidity of each detection point, and a total suspended particulate matter concentration monitor using the light scattering method to measure the concentration of total suspended particulate matter in the atmosphere. After sorting, obtain the average light intensity , average humidity and average total suspended particulate matter concentration of each topographic measurement sub-region.

[0020] Further, obtain the average light intensity , average humidity and average total suspended particulate matter concentration of each topographic measurement sub-region, and calculate the environmental error coefficient :

[0021]

[0022] Among them, represents the light intensity threshold of the lidar, represents the humidity threshold of the lidar, represents the total suspended particulate matter concentration threshold of the lidar.

[0023] Furthermore, when the environmental error coefficient is greater than 0, it indicates that the external environment of the current topographic measurement sub-region has a great influence on the measurement accuracy of the laser rangefinder, and an environmental error warning is sent out to prompt to find another time to measure this topographic measurement sub-region.

[0024] Furthermore, install devices such as lidar sensors, IMUs, and GPSs on the unmanned aerial vehicle, control the flight of the unmanned aerial vehicle according to the preset flight path, and the lidar continuously emits laser pulses to the ground and receives the reflected signals during the flight, recording the emission time, reception time, reflection intensity of the laser pulses, and GPS and IMU data at each time. The GPS provides the absolute position information of the lidar, and the IMU records the angular attitude of the platform (including roll, pitch, and yaw) to determine the precise orientation of the lidar.

[0025] Calculate the distance between the laser and the target object through the emission time and reception time of the laser pulse. Combine the GPS and IMU data to transform each laser point from the local coordinate system of the lidar to the global coordinate system. Combine the calculated three-dimensional coordinates (X, Y, Z) and reflection intensity information of each laser point into point cloud data to construct the first point cloud database.

[0026] Furthermore, project the three-dimensional point cloud data in the first point cloud database onto a two-dimensional plane, divide the two-dimensional plane into evenly sized point cloud grids with an area of 1 square meter, number them, and count the number of point clouds on each point cloud grid .

[0027] Furthermore, obtain the number of point clouds on each point cloud grid , the environmental error coefficient of the point cloud grid corresponding to the topographic measurement sub-region and the initial topographic complexity , and calculate the complexity of each point cloud grid :

[0028]

[0029] Among them, c represents the sequential number of the point cloud grid within the same topographic measurement sub-region.

[0030] Furthermore, when the complexity of each point cloud grid When it is greater than 1.2 times the average grid complexity, it indicates that the spatial complexity of the area corresponding to the current grid is high, and it is necessary to improve the data and output the GPS position coordinates corresponding to the center point of the point cloud grid outward. The average grid complexity is the average of the complexities of all point cloud grids in all topographic measurement sub-areas. of all.

[0031] Furthermore, organize all the output GPS position coordinates, mark them as the fine measurement area, use a drone equipped with lidar to conduct 2 terrain data measurements on the fine measurement area, analyze and form the second point cloud data, and fuse the second point cloud data into the first point cloud database according to the GPS coordinates to form complete point cloud data.

[0032] Furthermore, use point cloud processing software (such as CloudCompare, GlobalMapper, Lidar360, etc.) to classify the complete point cloud data, distinguish different types of point cloud data such as ground points, vegetation points, building points, etc., extract elevation information from the classified ground point cloud, generate a digital elevation model (DEM), and through terrain surface reconstruction algorithms (such as TIN, Grid, etc.), convert the DEM data into a terrain surface model that is easier to represent and analyze. According to the DEM data or the terrain surface model, draw contour lines and output the measured topographic map.

[0033] Furthermore, perform georegistration on the initial topographic map and the measured topographic map to accurately align them in spatial position. According to the division of the topographic measurement sub-areas, use GIS software to extract the number of contour lines within the topographic measurement sub-areas in the measured topographic map and the elevation value of each contour line , calculate the measured terrain complexity of each topographic measurement sub-area in the measured topographic map :

[0034]

[0035] Among them, represents the maximum value of the contour line elevation values within the same topographic measurement sub-area in the measured topographic map, represents the minimum value of the contour line elevation values within the same topographic measurement sub-area in the measured topographic map.

[0036] Furthermore, obtain the measured terrain complexity of each topographic measurement sub-area in the measured topographic map and the initial terrain complexity of each topographic measurement sub-area , calculate the difference between the two. If the difference is greater than 1, it is considered that this topographic measurement sub-area is the different part and is output as the changed area of the national territorial space planning.

[0037] (III) Beneficial effects

[0038] The present invention provides a topographic survey system for territorial spatial planning, which has the following beneficial effects:

[0039] 1. By collecting historical topographic maps of the area to be measured, evenly dividing the area to be measured into topographic survey sub-areas with equal areas according to the historical topographic maps, calculating the topographic complexity of each topographic survey sub-area, and determining the measurement method for each topographic survey sub-area. By reasonably dividing the topographic survey sub-areas and determining the measurement method according to the topographic complexity, it is possible to avoid wasting resources on unnecessary high-precision measurements, thereby reducing the measurement cost.

[0040] 2. Collect the environmental data of the topographic survey sub-areas during the data collection time of the lidar, calculate the environmental error coefficient, and issue an environmental error warning. It is possible to understand the environmental conditions of the measurement area in real time, identify in advance the risk of measurement errors caused by environmental factors, provide warning information for the measurement personnel, so that they can adjust the measurement plan or take corresponding measures in time to avoid data distortion.

[0041] 3. Use a drone to carry a lidar to measure the topographic data of the topographic survey sub-areas, construct a first point cloud database, project the three-dimensional point cloud data in the first point cloud database onto a two-dimensional plane, divide the two-dimensional plane into evenly distributed point cloud grids with an area of 1 square meter, and calculate the complexity of each point cloud grid , mark the fine measurement areas, conduct two measurements of the topographic data, analyze and form the second point cloud data, and fuse the second point cloud data into the first point cloud database according to the GPS coordinates to form a complete point cloud data. Conducting secondary measurements on the marked fine measurement areas can further improve the data accuracy of these areas, which helps to ensure the accuracy and reliability of the entire topographic data set.

[0042] 4. Generate a measurement topographic map based on the complete point cloud data, compare the initial topographic map with the complete topographic map, identify the different parts, and output them as the changed areas of the territorial spatial planning. It is possible to accurately identify the changes in natural elements such as topography, landform, and vegetation cover, which helps to more accurately grasp the current situation and development trend of the regional natural environment. Based on the accurate topographic change information, the planning layout can be adjusted and optimized more reasonably. Description of the Drawings

[0043] Figure 1 It is a schematic structural diagram of a topographic survey system for territorial spatial planning according to the present invention. Detailed Embodiments

[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0045] Please refer to Figure 1 , the present invention provides a topographic survey system for territorial spatial planning, including:

[0046] An acquisition area division module, which is used to collect historical topographic maps of the area to be measured, evenly divide the area to be measured into topographic survey sub-areas with equal areas according to the historical topographic maps, calculate the topographic complexity of each topographic survey sub-area, and determine the measurement method for each topographic survey sub-area.

[0047] Obtain the historical topographic map of the area to be measured through accessing online platforms and databases such as the National Geospatial Data Cloud and Tianditu as the initial topographic map, use GIS software (such as ArcGIS, QGIS, etc.) or programming tools (such as Python combined with the GeoPandas library) to divide the initial topographic map into grids of equal size, each grid is a topographic survey sub-area, and number them sequentially.

[0048] Use GIS software to extract the number of contour lines within the topographic survey sub-area and the elevation value of each contour line , and calculate the initial topographic complexity of each topographic survey sub-area :

[0049]

[0050] Wherein, a represents the sequential number of each topographic survey sub-area, represents the maximum value of the contour line elevation values within the same topographic survey sub-area, represents the minimum value of the contour line elevation values within the same topographic survey sub-area.

[0051] According to the size of the initial topographic complexity , sort the topographic survey sub-areas from large to small. The top 30% of the sorted topographic survey sub-areas are marked as complex terrain areas, and the lidar is set to a high sampling frequency for data acquisition. The last 30% of the sorted topographic survey sub-areas are marked as simple terrain areas, and the lidar is set to a low sampling frequency for data acquisition. The remaining topographic survey sub-areas are marked as conventional terrain areas, and the lidar is set to a conventional sampling frequency for data acquisition.

[0052] By collecting the historical topographic maps of the area to be measured, evenly dividing the area to be measured into topographic measurement sub-areas with equal areas according to the historical topographic maps, calculating the topographic complexity of each topographic measurement sub-area, and determining the measurement method for each topographic measurement sub-area. By reasonably dividing the topographic measurement sub-areas and determining the measurement method according to the topographic complexity, it is possible to avoid wasting resources on unnecessary high-precision measurements, thereby reducing the measurement cost.

[0053] The measurement environment analysis module is used to collect the environmental data of the topographic measurement sub-area during the time when the lidar collects data, calculate the environmental error coefficient, and issue an environmental error warning.

[0054] Randomly set several detection points within the topographic measurement sub-area, use a light intensity meter to detect the light intensity of each detection point, a humidity sensor to detect the humidity of each detection point, and a total suspended particulate matter concentration monitor using the light scattering method to measure the concentration of total suspended particulate matter in the atmosphere. After sorting, obtain the average light intensity of each topographic measurement sub-area and average humidity and average total suspended particulate matter concentration .

[0055] Obtain the average light intensity and average humidity and average total suspended particulate matter concentration of each topographic measurement sub-area, and calculate the environmental error coefficient :

[0056]

[0057] Among them, represents the light intensity threshold of this lidar, represents the humidity threshold of this lidar, represents the total suspended particulate matter concentration threshold of this lidar.

[0058] The influence of light intensity on the accuracy of laser ranging is not linear. Within a certain range, the increase in light intensity may gradually reduce the ranging accuracy, but when the light intensity exceeds a certain threshold, due to the saturation of the receiver or other physical limitations, the ranging accuracy will drop sharply. During the experiment, gradually increase the light intensity and observe the change of the ranging accuracy. When the ranging accuracy starts to drop sharply, it can be considered that the light intensity has exceeded the threshold of this laser rangefinder at this time.

[0059] When the environmental error coefficient is greater than 0, it means that the external environment of the current topographic measurement sub-area has a great influence on the measurement accuracy of the lidar, and an environmental error warning is sent outwards to prompt to find another time to measure this topographic measurement sub-area.

[0060] Collect the environmental data of the topographic measurement sub-region during the data collection time of the lidar, calculate the environmental error coefficient, and issue an environmental error warning, so as to understand the environmental conditions of the measurement area in real time, identify in advance the measurement error risks that may be caused by environmental factors, provide warning information for the measurement personnel, and enable them to adjust the measurement plan or take corresponding measures in a timely manner to avoid data distortion.

[0061] The data acquisition module uses a drone carrying a lidar to measure the topographic data of the topographic measurement sub-region, constructs a first point cloud database, projects the three-dimensional point cloud data in the first point cloud database onto a two-dimensional plane, divides the two-dimensional plane into uniform point cloud grids with an area of 1 square meter, and calculates the complexity of each point cloud grid , mark the fine measurement area, conduct two topographic data measurements, analyze and form the second point cloud data, and fuse the second point cloud data into the first point cloud database according to the GPS coordinates to form complete point cloud data.

[0062] Install devices such as lidar sensors, IMUs, and GPSs on the drone, control the drone to fly according to the preset route, the lidar continuously emits laser pulses to the ground and receives the reflected signals during flight, and records the emission time, reception time, reflection intensity of the laser pulses, and GPS and IMU data at each time. GPS provides the absolute position information of the lidar, and the IMU records the angular attitude of the platform (including roll, pitch, and yaw) to determine the accurate orientation of the lidar.

[0063] Calculate the distance between the laser and the target object through the emission time and reception time of the laser pulse. Combine the GPS and IMU data to convert each laser point from the local coordinate system of the lidar to the global coordinate system. Combine the calculated three-dimensional coordinates (X, Y, Z) and reflection intensity information of each laser point into point cloud data to construct a first point cloud database.

[0064] Project the three-dimensional point cloud data in the first point cloud database onto a two-dimensional plane, divide the two-dimensional plane into uniform point cloud grids with an area of 1 square meter, number them, and count the number of point clouds on each point cloud grid .

[0065] Obtain the number of point clouds on each point cloud grid 、the environmental error coefficient of the point cloud grid corresponding to the topographic measurement sub-region and the initial topographic complexity , calculate the complexity of each point cloud grid :

[0066]

[0067] Among them, cIndicates the sequential number of point cloud grids within the same topographic survey sub-region.

[0068] When the complexity of each point cloud grid is greater than 1.2 times the average grid complexity, it indicates that the regional spatial complexity corresponding to the current grid is high, and data needs to be improved. The GPS position coordinates corresponding to the center point of the point cloud grid are output outward, where the average grid complexity is the average of the complexities of all point cloud grids in all topographic survey sub-regions .

[0069] Sort out all the output GPS position coordinates, mark them as fine measurement areas, use a drone equipped with lidar to conduct 2 terrain data measurements on the fine measurement areas, analyze and form the second point cloud data, and fuse the second point cloud data into the first point cloud database according to the GPS coordinates to form complete point cloud data.

[0070] Use a drone equipped with lidar to measure the terrain data of the topographic survey sub-region, construct the first point cloud database, project the three-dimensional point cloud data in the first point cloud database onto a two-dimensional plane, divide the two-dimensional plane into uniform point cloud grids with an area of 1 square meter, and calculate the complexity of each point cloud grid , mark the fine measurement areas, conduct 2 terrain data measurements, analyze and form the second point cloud data, fuse the second point cloud data into the first point cloud database according to the GPS coordinates to form complete point cloud data. Conducting secondary measurements on the marked fine measurement areas can further improve the data accuracy of these areas, which helps to ensure the accuracy and reliability of the entire topographic data set.

[0071] The topographic data analysis module generates a measurement topographic map based on the complete point cloud data, compares the initial topographic map with the measurement topographic map, identifies the different parts, and outputs them as the changed areas of the national territorial space planning.

[0072] Use point cloud processing software (such as CloudCompare, GlobalMapper, Lidar360, etc.) to classify the complete point cloud data, distinguish different types of point cloud data such as ground points, vegetation points, building points, etc., extract elevation information from the classified ground point clouds, generate a digital elevation model (DEM), and through terrain surface reconstruction algorithms (such as TIN, Grid, etc.), convert the DEM data into a terrain surface model that is easier to represent and analyze. According to the DEM data or the terrain surface model, draw contour lines and output the measurement topographic map.

[0073] Geometrically register the initial topographic map and the measurement topographic map to make them accurately aligned in spatial position. According to the division of the topographic survey sub-region, use GIS software to extract the number of contour lines within the topographic survey sub-region in the measurement topographic map and the elevation value of each contour line , calculate the measured topographic complexity of each topographic measurement sub-region in the measured topographic map :

[0074]

[0075] Among them, represents the maximum value of the contour elevation values within the same topographic measurement sub-region in the measured topographic map, represents the minimum value of the contour elevation values within the same topographic measurement sub-region in the measured topographic map.

[0076] Obtain the measured topographic complexity of each topographic measurement sub-region in the measured topographic map and the initial topographic complexity of each topographic measurement sub-region , calculate the difference between the two. If the difference is greater than 1, it is considered that this topographic measurement sub-region is the different part, and the output is the changed area of the national territorial space planning.

[0077] Generate a measured topographic map based on the complete point cloud data, compare the initial topographic map with the complete topographic map, identify the different parts, and the output is the changed area of the national territorial space planning. It can accurately identify the changes in natural elements such as terrain, landform, and vegetation coverage, which helps to more accurately grasp the current situation and development trend of the regional natural environment. Based on the accurate terrain change information, the planning layout can be adjusted and optimized more reasonably.

[0078] The above embodiments can be implemented in whole or in part by software, hardware, firmware, or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution.

[0079] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0080] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should be covered within the protection scope of the present application.

Claims

1. A land space planning topographic survey system, characterized by: include: The acquisition area division module is used to collect the historical topographic map of the area to be measured, divide the area to be measured evenly into topographic measurement sub-areas of equal area according to the historical topographic map, calculate the terrain complexity of each topographic measurement sub-area, and determine the measurement method of each topographic measurement sub-area; The measurement environment analysis module is used to collect environmental data of the topographic measurement sub-area within the laser radar data collection time, calculate the environmental error coefficient, and issue an environmental error warning; The data acquisition module uses a drone equipped with a laser radar to measure the topographic data of the topographic survey sub-area, builds the first point cloud database, projects the three-dimensional point cloud data in the first point cloud database onto a two-dimensional plane, and divides the two-dimensional plane into uniform point cloud grids with an area of ​​1 square meter, and calculates the complexity of each point cloud grid. , mark the fine measurement area, conduct two terrain data measurements, analyze and form the second point cloud data, and merge the second point cloud data into the first point cloud database according to the GPS coordinates to form a complete point cloud data; Get the number of points on each point cloud grid , Environmental error coefficient of the point cloud grid corresponding to the topographic measurement sub-area and initial terrain complexity , calculate the complexity of each point cloud grid : in, c Indicates the sequential number of point cloud grids in the same topographic survey sub-area; The terrain data analysis module generates a survey topographic map based on the complete point cloud data, compares the initial topographic map with the survey topographic map, identifies the differences, and outputs them as the land space change area.

2. A land space planning topographic survey system according to claim 1, characterized in that: Extracting the number of contour lines within a topographic survey sub-area using GIS software and the elevation value of each contour line , calculate the initial terrain complexity of each topographic survey sub-area : in, a represents the sequential number of each topographic survey sub-area, It represents the maximum value of the contour elevation value in the same topographic measurement sub-area. Indicates the minimum value of the contour elevation within the same topographic measurement sub-area.

3. A land space planning topographic survey system according to claim 2, characterized in that: Based on the initial terrain complexity The topographic measurement sub-areas are sorted from large to small according to their size. The topographic measurement sub-areas in the first 30% are marked as complex terrain areas, and the lidar is set with a high sampling frequency for data collection. The bottom 30% are marked as simple terrain areas, and the lidar is set with a low sampling frequency for data collection. The remaining topographic measurement sub-areas are marked as regular terrain areas, and the lidar is set with a regular sampling frequency for data collection.

4. A land space planning topographic survey system according to claim 1, characterized in that: Several detection points are randomly set in the topographic measurement sub-area. The light intensity of each detection point is detected by a light meter, the humidity sensor is used to detect the humidity of each detection point, and the light scattering monitor is used to measure the total suspended particulate matter concentration in the atmosphere. After sorting, the average light intensity of each topographic measurement sub-area is obtained. , average humidity and the average total suspended particulate matter concentration .

5. A land space planning topographic survey system according to claim 4, characterized in that: Get the average light intensity for each topographic sub-area , average humidity and the average total suspended particulate matter concentration , calculate the environmental error coefficient : in, Represents the light intensity threshold of the laser radar. Indicates the humidity threshold of the lidar, Indicates the total suspended particulate matter concentration threshold of the lidar; When the environmental error coefficient When it is greater than 0, an environmental error warning is issued.

6. A land space planning topographic survey system according to claim 1, characterized in that: Project the 3D point cloud data in the first point cloud database onto a 2D plane, divide the 2D plane into uniform point cloud grids with an area of ​​1 square meter, and count the number of point clouds on each point cloud grid. .

7. The land space planning topographic survey system according to claim 1, characterized in that: When the complexity of each point cloud grid When the grid complexity is greater than 1.2 times the mean value, the GPS position coordinates corresponding to the center point of the point cloud grid are output, where the mean value of the grid complexity is the complexity of all point cloud grids in all terrain measurement sub-areas. The mean of .

8. The land space planning topographic survey system according to claim 1, characterized in that: Geo-reference the initial topographic map with the survey topographic map and use GIS software to extract the number of contour lines within the topographic sub-area in the survey topographic map and the elevation value of each contour line , calculate the measurement terrain complexity of each topographic measurement sub-area in the measurement terrain map .

9. A land space planning topographic survey system according to claim 8, characterized in that: Get the measured terrain complexity of each topographic survey sub-area in the measured terrain map and the initial terrain complexity of each topographic sub-area , calculate the difference between the two, if the difference is greater than 1, the topographic survey sub-area is considered to be the difference part, and the output is the land space change area.

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