CN116429069A

CN116429069A - Underwater and near-shore integrated topographic mapping data production method

Info

Publication number: CN116429069A
Application number: CN202310285173.1A
Authority: CN
Inventors: 张宙; 吴波; 刘小鹏; 赵映帅; 连恒; 姬霖; 刘广辉; 张金刚; 魏刚; 苏航
Original assignee: Second Topographic Survey Team Of Ministry Of Natural Resources (third Surveying And Mapping Engineering Institute Of Shaanxi Province)
Current assignee: Second Topographic Survey Team Of Ministry Of Natural Resources (third Surveying And Mapping Engineering Institute Of Shaanxi Province)
Priority date: 2023-03-22
Filing date: 2023-03-22
Publication date: 2023-07-14

Abstract

The invention discloses an underwater and near-shore integrated topographic mapping data production method, and relates to the technical field of topographic mapping. The invention integrates modern geospatial information technologies such as a multi-beam sounding system, a single-beam sounding system, a mobile navigation positioning system, a low-altitude aerial photogrammetry system, a geographic information system and the like, and designs a set of digital line drawing DLG, a digital surface model DSM, a digital elevation model DEM and a digital orthophoto drawing DOM mapping data production technical method which are integrated underwater and near shore; according to the invention, the mathematical references of underwater and near-shore data are ensured to be unified by unifying ground base stations and mobile positioning reference points; the invention ensures the uniformity of the types of underwater and near-shore data by dividing the process data and the result data; the invention ensures the unification of data formats through unified data processing flow and fusion method; the invention ensures the unification of the precision of the data through the unification of the precision control flow and the sampling standard.

Description

Underwater and near-shore integrated topographic mapping data production method

Technical Field

The invention relates to the technical field of topographic mapping, in particular to an underwater and near-shore integrated topographic mapping data production method.

Background

The topographic map data typically includes digital line Drawings (DLGs), digital Surface Models (DSMs), digital Elevation Models (DEMs), digital Orthophotomaps (DOM). In the past, due to the limitations of technical level, operation condition and the like, foundation mapping is often cut off to be above a career line, and obvious leakage exists in underwater topography data.

The data result generally comprises water depth data, water level data, sound velocity data and the like, and is inconsistent with the result content, format and the like of the offshore land topography data.

The method is characterized in that the scheme is independently provided in the aspect of underwater and near-shore integrated topographic data production, no integrated data acquisition, processing and product manufacturing scheme exists between underwater data and near-shore data, and the problems of non-uniform mathematical standard, non-uniform type, non-uniform format, non-uniform precision, flares in edge connection and the like exist between the underwater data and the near-shore data.

Disclosure of Invention

The invention provides a method for producing underwater and near-shore integrated topographic mapping data, which comprises the following steps:

based on the control of the layout map root of the positioning reference station system, unifying the topography mathematical references of underwater and coastal lands;

The underwater point cloud data acquisition is carried out through the sounding system, and the underwater point cloud data is processed by combining sound velocity data and water level data acquired by the water level station, so that mapping of underwater topography is completed;

carrying out unmanned aerial vehicle aerial photogrammetry and photo control measurement on the offshore land, and creating a stereoscopic model based on measurement results;

and carrying out data edge connection and integration processing on the underwater topography mapping result and the near-shore topography mapping result to generate an underwater and near-shore integrated digital line drawing map, an underwater and near-shore integrated digital surface model, an underwater and near-shore integrated digital elevation model and an underwater and near-shore integrated digital orthophoto map.

Further, the completing the acquisition and the processing of the underwater data specifically includes:

based on Beidou navigation positioning reference station system layout map root control;

establishing a temporary water level station and acquiring water level data;

and acquiring underwater point cloud data by adopting a multi-beam sounding system and a single-beam sounding system. The multi-beam sounding system specifically comprises survey line layout, equipment installation and debugging, attitude parameter calibration, full coverage data acquisition and the like, and the single-beam sounding system specifically comprises survey line layout, equipment installation and debugging, dynamic draft measurement and stability experiment, non-full coverage data acquisition and the like;

Acquiring sound velocity profile data in different areas and different time periods;

and carrying out correction processing on the original acquired point cloud data by combining the data such as sound velocity and water level to form underwater point cloud data.

Further, the completing the acquiring and processing of the offshore data specifically includes:

carrying out aerial photography measurement of the unmanned aerial vehicle, determining the type of the unmanned aerial vehicle, ground resolution and other aerial photography parameters according to the conditions of a measurement area range, achievement requirement precision, existing data and the like, carrying out aerial design, carrying out field survey and selection of take-off and landing sites before aerial photography flight, fully checking an unmanned aerial vehicle system during aerial photography implementation, monitoring the state of the unmanned aerial vehicle at any time in the aerial photography process, and finally obtaining images and then checking the images;

performing photo control measurement, taking a national B, C-level GPS control point as a starting point or adopting a CORS technology, performing GNSS measurement to obtain the observation information of a photo control point WGS84 coordinate system or a 2000-national geodetic coordinate system, and obtaining the plane coordinate of the 2000-national geodetic coordinate system of the photo control point and the elevation of a 1985-national elevation reference by utilizing the quasi-geodetic level refinement result elevation anomaly solution;

based on field image control point achievements, unmanned aerial vehicle aerial photography achievements, camera files and the like, the automatic aerial triangulation system adopting light beam methods such as PAT-AAT, GXP-AAT, pixel Grid and the like is adopted. And performing space three encryption according to the process flows of creating regional catalogues and related files, matching and editing connection points, measuring ground control points, regional network adjustment, encryption point edge grafting of adjacent regions, result inspection and the like, and forming near-shore space three encryption results.

Further, the generating the underwater and near shore integrated digital line drawing includes editing database data, and specifically includes:

constructing an irregular triangular network for the underwater three-dimensional point cloud data obtained after the inspection is error-free, generating underwater contour lines through interpolation, wherein the contour lines are continuous and smooth, the trend and the density degree of the underwater contour lines reflect the characteristic of the terrain distribution of a measurement area, and the design of the underwater contour distance is based on the fact that the trend and the gradient change degree of the terrain of the measurement area can be reflected;

establishing a three-dimensional relation based on the air-to-three encryption result, carrying out three-dimensional acquisition, importing three-dimensional acquisition data into editing software, and carrying out data editing and arrangement on various elements with reference to the field regulating drawing sheet;

when editing the linear elements, the density of the points is based on the principle that the geometric shape is not distorted, so that the smoothness of the lines is ensured, redundant suspension exists in data, the lines cannot be obtained from intersection, adhesion, knotting and repetition, the curves cannot be obviously deformed and broken lines, and short burrs and triangles cannot exist;

the dot elements are divided into three forms of marking points, positioning points and directed points; the directional points are used for representing punctiform drawing symbols represented according to the real direction, the acquisition starting point is a positioning point of the ground feature, the end point indicates the direction, the direction is calculated clockwise from the north direction, and the angle value is 0-360 degrees;

The line elements are divided into three forms of lines, a central line and directional lines; the element symbol main body is kept at the right side of the digital advancing direction during directional line acquisition;

the data layer without data content is not needed to generate an empty data layer;

the attribute items allowed to be empty in the attribute table are empty when no attribute value exists, namely, the attribute items are not assigned, and the attribute items are represented by a "/" interval when the attribute items have a plurality of different values;

nodes are not formed when the solid fields are intersected in a stereo mode, and the nodes are formed when the solid ground planes are intersected;

the public edges with various attributes are collected only once, and other layers of public parts are copied and generated, and respective classification codes are assigned;

after the elements of each layer are overlapped, the relationship should be kept coordinated, for example, the relationship between the water system and the landform and the relationship between the ground object and the water system, and the topological tolerance of the elements is generally not more than 0.001 meter;

the method comprises the steps of integrating the near-shore surveying and mapping result and the underwater topography surveying and mapping result, and coordinating and processing all elements of the border region of the near-shore surveying and mapping result and the underwater topography surveying and mapping result during integration, so that the graph surface is rationalized, and blank areas are avoided; in the integration treatment process, if the edge connecting area is found to be blank, the blank area needs to be subjected to complement measurement by adopting a full-field mapping mode, and the blank area is edited again to form a map.

Further, the generating the underwater and near shore integrated digital line drawing further includes editing graphic data, specifically including:

the symbol color value of the graphic data accords with the requirements of the drawing specification, and the symbol library templates are uniformly manufactured and provided so as to ensure the uniformity of the graphic data;

the representation of the ground object elements should reflect the distribution characteristics of the ground object, the relationship among the elements is coordinated reasonably, when the elements such as the ramp, the overpass side line and the like are crossed in a three-dimensional way, the lower layer is partially broken by the upper layer according to the projection principle, and the upper layer is kept complete;

the gland relation among various elements is processed, the principle of the element relation is that the element relation does not influence the graph reading, and the element symbols are adhered, gland or gapped but do not influence the graph reading, so that editing treatment can not be carried out; the same color elements generally cannot be mutually covered, if the same color mutual cover appears, the image is affected clearly and can not be solved by displacement, and the representation can be disconnected from the relatively secondary ground object; the gland among the different color elements is represented according to the requirements of the drawing, but the gland among the marks and the independent feature symbols cannot be stamped;

the mutual relations among the elements should be consistent, and the relation between the resident places and the road, the river and the bridge, the contour lines and the ground, the landform and the water system, the boundary and the river and the road are not influenced;

The graph data is consistent with the database data in a layering manner, and redundant layers and attribute items are not allowed to be contained;

in the process of editing graphic data, if the database data is found to have a significant problem affecting graphic expression, the database data should be modified to ensure that the final result meets the requirements;

elements and attributes in database data need to be correctly represented; the elements which need to be represented in the database data but do not need to be symbolized in the graphic data; such as: the road center line, the water system structure line, the slope lower line and the like are measured according to the proportion;

independent features collected according to a planar scale generate independent symbols in the center of the plane according to the requirements of the drawing, such as: chimney, water tower, granary, pavilion, independent open-air equipment;

when the density of the independent ground object is overlarge and the symbols are mutually covered, the size of the symbols is allowed to be properly reduced, the reduction rate is not more than 0.8, or the secondary ground object symbols are moved;

various broken line element symbols should be noted that they are joined, intersect at the real part when intersecting, intersect with the inner contour line at the real part, such as time river, small road, boundary;

when the natural geographic element contradicts the artificial building element, moving the artificial building element; moving the secondary element when the primary element contradicts the secondary element; when the independent feature contradicts other elements, moving the other elements;

The stacking sequence needs to satisfy: the planar, linear and dot elements are arranged from bottom to top; the linear elements are arranged from bottom to top according to landforms, vegetation, rivers and other linear elements; the boundary element is located above all the linear elements; the independent feature symbol is above the linear symbol; text is noted over all elements; the profile is finished at the uppermost layer; the inner graph profile and the square inner network line are generated by theoretical values, and the final result is not marked;

the notation needs to satisfy: the annotation is unified to use the Chinese character library, the words which are not in the character library and are rare should be unified spelling in the graphic data editing software; the characters cannot be mutually covered, various names and marks, water-containing systems and contour marks cannot be covered by other ground object symbols; various marks do not need to cover boundaries and are marked in the corresponding government area range; various marks can not cover road intersections, resident ground entrances and other main ground objects; the various marks are not generally covered by the coordinate grids, especially the intersections of the coordinate grids;

the adjacent pictures must be connected, and the positions, the attributes and the line types of the elements should be noted when the pictures are connected;

after the graphic data is completed, the graphic data and the database data are subjected to registration inspection, and the plane positions of other feature elements are kept consistent except for the required displacement of individual features.

Further, the generating the underwater and near shore integrated digital surface model specifically includes:

DSM generation, DSM editing, and map splicing and cropping, wherein:

in the generation of DSM, the DSM should correctly reflect the space position and morphological characteristics of the earth surface and the natural or permanently fixed artificial ground feature elements on the earth surface, including residential land and facilities, overhead traffic, stereo pipelines and vegetation; acquiring dense point clouds based on the space-time three-encryption result by adopting an image automatic matching method, and fusing the point clouds acquired by underwater editing with characteristic points and lines with surface elevation information of houses, bridges and the like to acquire DSM conforming to the surface morphology; re-matching or interpolating the non-data area with the area range;

in the DSM editing, the DSM does not represent an air dynamic object, a temporary stacking object, a static ground object parked on the ground and a moving dynamic ground object; the ground clutter area is expressed roughly according to actual conditions, so that no rough difference is ensured; the width of the artificial ground object is not represented when the width is smaller than 2 meters; the transportation facility shall represent an overhead section; the surface features of the surface model can not be completely obtained by the grid DSM without processing, and the precision is not required; the forests should express the periphery of the crown of each tree, and the forests should express the crown tops connected together; dynamic floating objects in the water are not reserved; the underwater static elements need to be reserved;

In the process of picture splicing and cutting, before picture splicing, the heights of same-name grid points in the edge splicing overlapping zone are checked, and for the poor out-of-limit points, the data splicing is reasonable, the transition is smooth and natural according to the three-dimensional model, and the overlapping zone of a certain grid is ensured between the edge splicing data; performing data mosaic on the basis of poor DSM edge connection and meeting the specified requirements, and taking the number of each homonym lattice point Gao Chengqu participating in the edge connection as the elevation of the lattice point after the edge connection; the adjacent DSMs are inlaid, so that a crack phenomenon does not occur, and the elevation values of the overlapped parts are consistent; and cutting the data according to a specified range to generate a graph DSM.

Further, the generating the underwater and near shore integrated digital elevation model specifically includes:

extracting elements with elevation information, collecting characteristic data, generating DEM, editing DEM and splicing and cutting a drawing, wherein:

in the extraction of the information elements with the elevations, the contours and the elevations Cheng Zhuji points are extracted from the vector data, the contours and the elevations are edited, topology errors, attribute errors and elevation errors are eliminated, and mutual contradiction among the elements is processed;

the characteristic data acquisition is to acquire other characteristic points and lines required by DEM manufacture; the landform characteristic points are selected at mountainous heads, concave lands, saddle parts and landform transformation positions, and the characteristic lines comprise dam, river levee, ridge line, valley line, slope line, landform elements such as scarps, ridges, lands, sills and the like which do not reach the selected index, and the lower line of the landform elements not according to the scale; characteristic points do not need to be acquired at the equal-inclination position, and the characteristic points and the characteristic lines cannot be too close; collecting the side lines of the road according to the proportion; in order to ensure the DEM range, the characteristic line at the free edge should at least collect 10 mm on the line outside graph of the operation range;

In the DEM generation, the landform elements extracted from the vector elements and other collected characteristic points and lines are subjected to processing such as irregular triangular mesh construction, interpolation and the like to generate a DEM result; when TIN is generated, in order to ensure the precision of the image edge DEM, the range of TIN should be larger than the range of the image outline; constructing TIN by using elevation element data, checking the rationality of the relation between the triangular net and the contour line, and reconstructing the TIN after adding characteristic points in the unreasonable flat triangle; and interpolating according to the required grid size on the basis of the TIN data to generate the DEM. An irregular triangular net interpolation algorithm is generally adopted; for a flat area or a terrain breaking area with sparse contour information, a grid interpolation method based on distance change and a grid interpolation method based on terrain features are adopted;

in the DEM editing, the key points of the DEM editing comprise contour lines, such as lake and reservoir shorelines, areas with unclear image textures, areas with complicated ground features and broken landforms and model joints; the DEM is required to reflect the characteristics of landforms, including natural landforms and artificial landforms with a certain scale, and is required to cut into the ground for residential lands and forest areas; for highway bridges, railway bridges and overhead roads, the DEM shall represent ground and water surface elevations, but not bridge deck elevations; the horizontal cultivated land should be kept horizontal, and no obvious pyramid shape can appear; ensuring reasonable road and river section elevation according to the scale, wherein the elevation difference is not more than 0.5 times of the DEM Gao Chengzhong error in principle;

In the process of picture splicing and cutting, before picture splicing, the heights of same-name lattice points in the joint overlapping zone are checked, and the poor out-of-limit points are modified according to a three-dimensional model, so that reasonable data splicing and smooth and natural transition are ensured; the overlapping band of a certain grid is ensured between the edge data; data mosaic is carried out on the basis that the DEM joint is poor and meets the specified requirement, and the numbers of the homonymous grid points Gao Chengqu participating in the joint are used as the grid point elevation after the joint; after the adjacent DEM is inlaid, no crack phenomenon occurs, and the elevation values of the overlapped parts are consistent; and cutting the data according to a specified range to generate a picture DEM.

Further, the generating the underwater and near shore integrated digital orthophoto map specifically includes:

DEM for image correction, image mosaic and cropping and image color adjustment, wherein:

in the DEM for image correction, the grid size and the grid point precision and the grid point range of the DEM meet the digital orthophoto correction requirement;

in the image correction, digital differential correction and image resampling are carried out on the image by using DEM data to generate a digital orthographic image; for image drawing, overhead bridges and the like, a method of locally and properly correcting the DEM can be adopted to correct the images; amplifying the orthophoto result once in a printing size state to ensure no pattern drawing phenomenon; the corrected image and the topographic map have no more overlay error than the error in the planar position of the topographic map, and elements with larger projection difference on the image do not perform overlay inspection, such as buildings, palisades and pipelines;

In the image mosaic and cutting, the edge joint difference of the same-name images after the correction of the images meets the error requirement in a specified plane; in principle, images with better image quality are selected during embedding, and the images have the conditions of cloud, shadow and the like and are replaced by adjacent images as much as possible; attention is paid to the consistency of splicing during embedding, and obvious integral visual difference is not generated; when the inlaid line is selected, artificial facilities such as large buildings, bridges and the like are avoided as much as possible; the digital orthophoto data is cut in the stipulated scope, the storage format is uncompressed tiff format, save the tfw coordinate information file at the same time; under the condition that the free image is not full, the blank part is filled with white, and RGB values are 255, 255 and 255;

in image color adjustment, the digital orthophoto image should be clear, the texture information is rich, the image between the sheets is kept uniform in tone as much as possible, the contrast is moderate, and no trace is left on the image surface due to image processing.

Compared with the prior art, the underwater and near-shore integrated topographic mapping data production method provided by the invention has the beneficial effects that:

the invention unifies the topography mathematical references of underwater and near-shore land by unifying positioning reference points; the invention ensures the uniformity of the types of underwater and near-shore data by dividing the process data and the result data; after field data acquisition, the invention ensures the unification of data formats through a unified data fusion method; the invention ensures the unification of the precision of the data through the unification of the precision control flow and the sampling standard; the invention ensures that the data has no edge connection loopholes through water level difference, measurement mode and the like.

Drawings

FIG. 1 is a flow chart of an underwater and near shore integrated topographic mapping data processing method provided by the invention;

FIG. 2 is a flowchart of a method for acquiring and processing underwater data according to an embodiment of the present invention;

FIG. 3 is a flowchart of a method for offshore data acquisition and processing according to an embodiment of the present invention;

FIG. 4 is a flow chart of a method for producing an underwater and offshore integrated digital line drawing according to an embodiment of the present invention;

FIG. 5 is a flow chart of a method for producing an integrated digital surface model on the sea and near shore according to an embodiment of the present invention;

FIG. 6 is a flow chart of a method for producing an underwater and near shore integrated digital elevation model provided by the invention;

FIG. 7 is a flow chart of the method for producing an underwater and near shore integrated digital orthographic image according to the present invention.

Detailed Description

Embodiments of the present invention will be further described with reference to fig. 1 to 7. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.

Example 1: as shown in fig. 1-7, the invention provides an underwater and near-shore integrated topographic mapping data processing method, which specifically comprises the following steps:

1. Underwater data acquisition and processing technical method

1.1 production technical Process

The flow of the underwater data acquisition and processing production technology is shown in figure 2.

1.2 Water level measurement

(1) Water level station layout

The temporary water level stations are arranged near the upper, middle and downstream sides of the measuring section as much as possible according to the actual situation of the site. If there is a long-term or permanent water level station in the area, the actual measurement data of the station can be directly transcribed, but the high-level point must be simultaneously measured.

(2) Water level stand height Cheng Liance

The working level point elevation of the temporary water level station is measured in a branch line mode by utilizing the high-grade level point near the temporary water level station according to the three-level measurement requirement. The zero elevation of the water gauge is executed by adopting the requirement of four equal levels, and joint measurement is carried out from the working level point of the temporary water level station.

(3) Water level observation

The water level observation of the water level station is synchronous to be carried out 30 minutes before the beginning of the daily water depth measurement and 30 minutes after the end of the water depth measurement, so that the synchronism of the water depth measurement and the water level observation is ensured.

1.3 Multi-beam underwater topography measurements

(1) Line layout

The main line layout direction is selected to be parallel to one of the trend of the equal-depth line, the flow direction of the tide, the axis direction of the channel or the longest edge of the area according to the requirement of the project. The distance between the measuring lines is not more than 80% of the effective depth measurement width, and in important navigation water bodies, the distance between the measuring lines is not more than 50% of the effective depth measurement width.

(2) System installation and debugging

The underwater equipment includes a transducer, a surface acoustic velocity meter. The water plant comprises a POS-MV, deck control unit. And performing assembly calibration on the assembly.

(3) Sound velocity measurement

The sound velocity profile should be measured in a representative water area in the area before each operation, the radius of the control area of each sound velocity profile is not more than 20km, and the use time of each sound velocity profile data is not more than 1 day.

(4) Data acquisition

After the equipment calibration is completed, the data acquisition stage can be entered. Before data are collected, the previously designed partition measuring lines are imported into control collection software, and a driver runs strictly according to the measuring lines in the collection process. Simultaneously, three display screens are arranged to respectively display the underwater signal receiving condition, the real-time relative position condition of the ship and the survey line, the acquired data coverage and the working state condition of each device. In the measurement process, the ship speed control is important, and is generally controlled within 4-5 knots (1 knot=1.813 km/h) according to the system requirement. The recorded data files are named according to the starting time of each measuring line, and in order to ensure the measurement accuracy, it is noted that the recording of data is forbidden in the process of turning around the measuring ship.

1.4 Single Beam underwater topography measurements

(1) Line layout

When the single-beam depth finder is used for underwater topography mapping, the main depth finding line direction is perpendicular to the shoreline direction, the main depth finding line interval is 20 meters, the depth finding locating point interval is 5 meters, and the water depth finding abnormal position is used for encryption mapping.

(2) Installation of equipment

The underwater measurement system consists of a GPS receiver, a sounding instrument, a navigation system, a data acquisition system and a water depth data processing system. And performing assembly calibration on the assembly.

(3) Draft determination

The vessel for underwater topography mapping must perform a mobile draft determination for depth correction in subsequent water depth measurements, the determination method being as follows:

1) The transducer of the depth finder is fixed at the center or on the side of the ship.

2) The method selects the area with flat water bottom, hard substrate and representative water depth, and can meet various speed requirements of dynamic draft measurement.

3) And throwing a buoy in the measuring area, stopping the ship beside the buoy, accurately measuring the water depth by using a depth measuring instrument, measuring the water depth at the same position by using the ship at various different speeds, measuring more than 3 groups of depths at the same speed, and taking an average value after eliminating the influence of water level fluctuation.

4) The difference between the measured depth of the ship at different speeds and the measured depth at rest is the dynamic draft of the ship at that speed.

5) Under the condition that the wave is relatively small, the measuring ship enters the measuring route after the ship speed is stable, so that the influence of factors such as acceleration, deceleration, stormy waves and the like on the determination of the draft is avoided.

(4) Data acquisition

And (3) arranging a planned measuring line on the AutoCAD, introducing a submerged measuring system, setting parameters such as measuring point spacing and the like, and carrying out measuring point positioning and sounding.

2. Technical method for acquiring and processing offshore data

2.1 production technical Process

The flow of the offshore data acquisition and processing production technology is shown in figure 3.

2.2 unmanned aerial vehicle aerial photography

(1) Aerial photography partition

1) The aerial photography subareas are divided according to factors such as the maximum flight time limit of the aircraft, the flight direction of the aerial route, the average altitude difference of the areas and the like.

2) The span of the aerial photography zone should be as large as possible, and the aerial photography zone should not be broken too much. While taking into account the associated requirements of encryption and point placement schemes.

3) According to the endurance time of different unmanned aerial vehicle platforms, the integrity of a single route is guaranteed as much as possible, and if the single route needs to be split, the overlapping degree of at least 3 baselines needs to be guaranteed between the partitions.

4) If the flight heights of adjacent airlines in different subareas are inconsistent, at least one airline needs to be ensured to be laid in an overlapping manner between airlines.

(2) Route laying

1) The course coverage exceeds the shot boundary by not less than two base lines, and the lateral coverage exceeds the shot boundary by not less than 50% of the image frame. When the oblique image is acquired, the aerial photography range is reasonably set according to the specific condition of the sensor, the integrity of the model in the result range is ensured, the general course coverage exceeds the border of the aerial photography region by not less than three base lines, and the lateral coverage exceeds the border of the aerial photography region by not less than three routes.

2) The flight direction of the air course should be laid along the whole range of the area, if the area is covered with relatively straight valleys or hills, the flight direction of the air course should be laid along the valleys or hills as much as possible, and the flight direction of the air course can be along the east-west or the south-north direction when approaching east-west or north-south direction, if the flight direction of the air course is not affected obviously, the air direction can be referenced, so that the flight direction is parallel to the general wind direction of the area.

3) When laying the route, the main point should be avoided from falling into water as much as possible.

4) When the height difference of the area is large, the course laying should pay attention to that the heading overlapping degree of the highest point in the partition is not lower than 58%, and the side overlapping degree is not lower than 20%; the ground resolution of the lowest point of the forward photographic image in the subarea is better than 0.05 m, and the ground resolution of the lowest point of the oblique image looking down is better than 0.05 m.

(3) Aerial time

1) Aerial photography is carried out under the most favorable meteorological conditions, adverse effects of cloud shadows, snow, fog, haze and the like on photography and mapping are avoided or reduced as much as possible, and aerial photography images can be ensured to truly show details of the ground.

2) In order to avoid excessive contrast of the image brightness, the aerial photography flight is preferably selected to fly in cloudy weather or the aerial photography flight is preferably performed in the maximum period of the solar altitude, and the shadow multiple is preferably less than 1.

(4) Aerial image requirements

1) In order to ensure the imaging precision, the image result should be clear, fine and smooth and the tone should be clear.

2) The shooting sites POS data are in one-to-one correspondence with the photo numbers.

3) The ground resolution of the lowest point of the positive photographic image is better than 0.05 m, and the ground resolution of the lowest point of the oblique image is better than 0.05 m.

(5) Supplement and re-shoot

Absolute loopholes, relative loopholes and other serious defects in the aerial shooting process must be timely supplemented. The supplementary shooting should be carried out by adopting the same aerial shooting instrument. And (3) the whole route needs to be supplemented by the supplementary shooting in the aerial zone, such as the whole subarea needs to be supplemented by the supplementary shooting if holes exist among the aerial zones.

2.3 photo control measurement

(1) Requirement of image control point and point position

The target image of the control point should be clear, easy to distinguish, and the accuracy of in-situ recognition is not more than 20cm. If the point-shaped ground object center with the image smaller than 0.3mm is selected at the fine linear ground object intersection point with good intersection angle, the point-shaped ground object center with the image smaller than 0.3mm is obviously ground object corner points, and meanwhile, the point-shaped ground object center is a place with small elevation change; for positioning and measurement; the occluded ground object, the arc-shaped ground object, the shadow and the like should not be selected as point targets.

When the target condition contradicts the photo condition, the target condition should be considered seriously.

If the large-scale image control point selection of the area is difficult, target points should be properly distributed before aerial photography so as to meet the point selection requirement.

The field control point of the current test should meet the requirements of plane and elevation control at the same time.

(2) Image control point layout scheme

According to the arrangement scheme of the image control points, firstly, according to the unmanned aerial vehicle aerial photographing system, if the unmanned aerial vehicle is used to carry a PPK or RTK system, the necessary image control points are arranged according to different system conditions under the condition of rare control or no control, if the common unmanned aerial vehicle system is used, the regional domain network method is generally adopted to arrange the photo control points, the arranged image control points are all flat high points, and the baseline interval between the control points is not more than 8. Checkpoints should be deployed in the area network center (where accuracy is the weakest).

(3) Basic requirements for observing image control points and check points

The photo control point measurement is conditionally suitable to be combined with the CORS station system of I province, the GPS-RTK mode is adopted for measurement, and the quick static measurement mode meeting the precision requirement can also be adopted.

When RTK image control point is measured, the number of calendar elements is larger than 20, the coordinate of each observation plane is poorer, the elevation difference is not larger than 10cm, and the number of the measured calendar elements is taken as the final result. The field collected data of RTK measurement should be backed up and checked in time. When the image control point adopts GPS static mode measurement, the elevation adopts GPS elevation point conversion measurement. The maximum distance of the GPS baseline should not exceed 10km when using GPS elevation point conversion measurements.

The surrounding of the observation point of the rapid static measurement of the GPS is convenient for arranging receiving equipment and operating, the visual field is wide, and the height angle of the obstacle in the visual field is generally smaller than 15 degrees. Remote from high-power radio emission sources (such as television stations, microwave stations and the like), the distance is not less than 200m; away from the high voltage transmission line, the distance must not be less than 100m. Objects which are not interfered with the received satellite signals strongly are not needed near the point location, and a large area of water area is avoided as much as possible. During observation, the radio station must not be used within 50 meters of the antenna, and the intercom must not be used within 10 meters.

2.4 aerial triangulation

Based on field image control point achievements, unmanned aerial vehicle aerial photography achievements, camera files and the like, the automatic aerial triangulation system adopting light beam methods such as PAT-AAT, GXP-AAT, pixel Grid and the like is adopted. The method is carried out according to the technological processes of creating regional catalogues and related files, matching and editing connection points, measuring ground control points, regional network adjustment, encryption point edge grafting of adjacent regions, result inspection and the like.

3. Underwater and coastal integrated digital line Drawing (DLG)

3.1 production technical Process

The flow of the integrated Digital Line Graph (DLG) production technology under water and near shore is shown in figure 4.

3.2 database data editing

(1) And constructing an irregular triangular net for the underwater three-dimensional point cloud data obtained after the inspection is correct, and generating underwater contour lines through interpolation, wherein the contour lines are continuous and smooth. The trend and the density degree of the underwater contour line reflect the characteristics of the terrain distribution of the area, and the design of the underwater contour distance is based on the trend and the gradient change degree of the terrain of the area.

(2) And importing the three-dimensional acquisition data into editing software, and editing and arranging the data of various elements with reference to the field regulating drawing sheet.

(3) Data layering, element attribute items, attribute item definitions of the data layering, element selection and representation and the like are strictly executed according to relevant data specifications.

(4) The data item of which the data type is TEXT in the attribute value, wherein the characters of numerals, letters, "-" (middle bar line), "()" (bracket) and "/" (oblique line) and the like are all English half angles.

(5) The final data results are not marked.

(6) The inner contour lines and kilometer lines are generated by theoretical values, the coordinate network layer stores the complete inner contour lines generated by the theoretical values, other data layers do not store the complete inner contour lines, and if elements are intersected with the contour lines and closed to form polygons, only the section of inner contour lines which form closed polygons are copied and collected.

(7) When editing the linear elements, the density of the points is based on the principle that the geometric shape is not distorted, so that the smoothness of the lines is ensured, redundant suspension exists in the data, and the intersection, the adhesion, the knotting and the repetition are not obtained. The curve must not have obvious deformation and broken lines, short burrs and triangles.

(8) The dot elements are divided into three forms of marking points, positioning points and directed points. The directional points are used for representing punctiform drawing symbols represented according to the real direction, the acquisition starting point is a positioning point of the ground feature, the end point indicates the direction, the direction is calculated clockwise from the north direction, and the angle value is 0-360 degrees.

(9) The line elements are divided into three forms of lines, center lines and directional lines. The element symbol body should be kept to the right of the digitized advancing direction when the directed line is collected.

(10) The occurrence of empty faces is generally not allowed.

(11) The data layer without data content does not need to be generated with a null data layer. Attribute entries in the attribute table that are allowed to be empty should be empty (i.e., not assigned) when no attribute values are present. When the attribute term has a plurality of different values, it is denoted by "/" intervals.

(12) The solid and the ground are intersected in a stereo mode, no node is formed, and the solid and the ground are intersected to form the node.

(13) The common edges with various attributes are collected only once, and other layers of common partial copies are generated and assigned with respective classification codes.

(14) After the elements of each layer are overlapped, the relationship should be kept coordinated (such as the relationship between water system and landform, the relationship between ground feature and water system, etc.), and the topological tolerance of the elements is generally not more than 0.001 meter.

(15) And integrating the near-shore mapping result and the underwater topography mapping result, and coordinating and processing each element of the border region of the near-shore mapping result and the underwater topography mapping result during integration to rationalize the drawing surface and avoid blank areas. In the integration treatment process, if the edge connecting area is found to be blank, the blank area needs to be subjected to complement measurement by adopting a full-field mapping mode, and the blank area is edited again to form a map.

3.3 graphic data editing

(1) The symbol color values of the graphic data meet the requirements of the drawing specification, and the symbol library templates are uniformly manufactured and provided so as to ensure the uniformity of the graphic data.

(2) The representation of the ground object elements should reflect the distribution characteristics of the ground object, the relationship among the elements is coordinated reasonably, and when the elements such as the ramp, the overpass side line and the like are crossed in a three-dimensional way, the lower layer is partially broken by the upper layer according to the projection principle, and the upper layer is kept complete.

(3) The gland relation among various elements is processed, the principle of the element relation is that the element relation does not influence the graph reading, and the element symbols are adhered, gland or gapped but do not influence the graph reading, so that editing processing is not performed. The same color elements generally must not be mutually capped, and if the same color mutual capping occurs, the image clarity is affected and the solution cannot be achieved through displacement, the representation can be disconnected from the relatively minor ground object. The gland between the different color elements is represented according to the requirement of the drawing, but the gland between the marks and the marks of the independent features cannot be used.

(4) The mutual relations among the elements should be consistent, and the relation between the resident places and the road, the river and the bridge, the contour lines and the ground features, the landforms and the water system, the boundary and the river, the road and the like are not influenced.

(5) The graphics data is hierarchically consistent with the database data, and is not allowed to contain redundant layers and attribute items.

(6) In the process of editing graphic data, if the database data is found to have a significant problem affecting graphic expression, the database data should be modified to ensure that the final result meets the requirements.

(7) Elements and attributes in database data are correctly represented in the graphic data according to the schema. Elements in the database data that need to be represented, but elements in the graphic data that do not need to be represented, need not be symbolized. Such as: the road center line, the water system structure line, the slope lower line and the like according to the proportion.

(10) Independent features collected according to a planar scale generate independent symbols in the center of the plane according to the requirements of the drawing, such as: chimney, water tower, barn, kiosk, stand alone open air equipment, and the like.

(11) The density of the independent features is too high, and when the symbols are mutually covered, the size of the symbols is allowed to be properly reduced (the reduction rate is not more than 0.8) or the secondary feature symbols are moved.

(12) Various dashed element symbols should be noted as being joined, intersecting at the time of intersection with the interior contour line with the real part, e.g., time river, roadway, boundary, etc.

(13) Element relation processing

1) Avoidance relationship

When the natural geographic element contradicts the artificial building element, moving the artificial building element; moving the secondary element when the primary element contradicts the secondary element; when the independent feature contradicts other elements, the other elements are moved.

2) Stacking sequence

(1) The planar, linear and dot elements are arranged from bottom to top;

(2) the linear elements are arranged from bottom to top according to landforms, vegetation, rivers and other linear elements;

(3) the boundary element is located above all the linear elements;

(4) the independent feature symbol is above the linear symbol;

(5) text is noted over all elements;

(6) the profile is finished at the uppermost layer.

(7) The inner graph profile and the square inner net line should be generated by theoretical values (the final result is not marked).

(14) Annotation mark

1) The annotation is unified using a library of chinese characters. The words which are not in the word stock and are rarely used should be unified spelling in the graphic data editing software.

3) The characters must not be mutually covered, and various names (water-containing system, contour marks, etc.) must not be covered by other ground object symbols in principle.

4) Various marks do not need to cover boundaries and are marked in the corresponding government area range; various marks can not cover road intersections, resident ground entrances and other main ground objects; the various notes should not be pressed against the grid in general, and the grid intersections in particular.

(15) Adjacent panels must be bordered. The edge connection should be performed by paying attention to element positions, attributes, line types and the like.

(16) After the graphic data is completed, the graphic data and the database data are subjected to registration inspection, and the plane positions of other feature elements are kept consistent except for the required displacement of individual features.

4. Underwater and near shore integrated Digital Surface Model (DSM)

4.1 production technical Process

The process flow for the production of the underwater and offshore integrated Digital Surface Model (DSM) is shown in fig. 5.

4.2DSM Generation

The DSM should accurately reflect the spatial location and morphological characteristics of the earth's surface and of naturally or permanently fixed artificial ground elements on the earth's surface, including residential and facilities, overhead traffic, stereo lines, vegetation, and the like.

And obtaining dense point clouds based on the space-three encryption achievements by adopting an image automatic matching method, and obtaining DSM conforming to the surface morphology by fusing the point clouds obtained by underwater editing with characteristic points and lines of houses, bridges and the like with surface elevation information.

For non-data regions where the range of regions appears, a re-match or interpolation is performed.

4.3DSM editing

(1) The DSM does not represent dynamic objects in the air such as birds and airplanes, and static features such as temporary stacks and vehicles parked on the ground, and dynamic features such as moving vehicles and pedestrians are not retained.

(2) The ground surface clutter areas such as the construction area, the clutter ground and the demolition area are roughly represented according to actual conditions, and no rough differences exist.

(3) The width of the artificial ground object is less than 2 meters, which is not represented, for example, smaller houses, space between houses, narrower ditches, ridges and the like.

(4) Traffic facilities such as bridges, overhead roads, etc. should represent overhead sections.

(5) Special features (features where the grid DSM cannot fully acquire the surface model) are not processed, and no precision is required. For example, complex ground objects (heat dissipation towers, pagodas, pier-rack wire towers and the like) with a plurality of elevation values at the same plane position; ground objects with net-shaped appearance (cableways, wire meshes and the like); ground features with local movements (windmills, waterwheels, etc.); ground objects with smaller cross-sectional area (overhead pipelines such as power lines, communication lines, pipelines and the like, rod-shaped ground objects such as street lamps, electric poles and the like).

(6) The forests should express the crown periphery of each tree and the forests should express the crown tips linked together.

(7) Dynamic floating objects such as fish, shrimp and the like in the water are not reserved.

(8) Static elements such as underwater sunken ships, low-water pipelines, bridge piles and the like need to be reserved.

4.4 splicing and cutting of the image

(1) Before the picture splicing, the same-name lattice point elevation in the joint overlapping zone is checked, and the poor overrun points are modified according to the three-dimensional model, so that reasonable data splicing and smooth and natural transition are ensured. The overlapping band of a certain grid should be ensured between the edge data.

(2) And (3) data mosaic is carried out on the basis that the DSM joint is poor and meets the specified requirement, and the number of the homonymous grid points Gao Chengqu participating in the joint is used as the grid point elevation after the joint.

(3) No cracking phenomenon should occur after adjacent DSMs are inlaid, and the elevation values of the overlapped portions should be consistent.

(4) And cutting the data according to a specified range to generate a graph DSM.

5. Underwater and coastal integrated Digital Elevation Model (DEM)

5.1 production technical Process

The flow of the production technology of the underwater and offshore integrated Digital Elevation Model (DEM) is shown in fig. 6.

5.2 extraction of information elements with elevation

Contour lines and high Cheng Zhuji points are extracted from vector data, are edited, topology errors, attribute errors and elevation errors are eliminated, and mutual contradiction among elements is processed.

5.3 feature data acquisition

Other characteristic points and lines required for manufacturing the DEM are collected.

(1) The characteristic points of the topography are selected at mountains, concave lands, saddles, topography transformation positions and the like, and the characteristic lines comprise dams, river levees, ridge lines, valley lines, slope lines, landform elements such as scarps (ridges and lands) which do not reach the selected index, sills and the like, and the lower lines of the landform elements which are not in proportion. The feature points do not need to be acquired at the equal-inclination positions, and the feature points and the feature lines cannot be too close.

(2) And collecting the side lines of the road according to the proportion.

(3) To ensure the DEM range, the feature line at the free edge should be at least 10 mm from the line drawing of the working range.

5.4DEM Generation

And carrying out processing such as construction of an irregular triangle network, interpolation and the like on the geomorphic elements extracted from the vector elements and other collected characteristic points and lines to generate a DEM result.

In generating the TIN, in order to ensure the accuracy of the map edge DEM, the range of the TIN should be larger than the range of the map outline. And constructing the TIN by using the elevation element data, checking the rationality of the relation between the triangular net and the contour line, and reconstructing the TIN after adding the characteristic points to the unreasonable flat triangle.

And interpolating according to the required grid size on the basis of the TIN data to generate the DEM. An irregular triangle network (TIN) interpolation algorithm is generally adopted; for a flat area or a broken terrain area where contour information is rare, a grid interpolation method based on distance change, a grid interpolation method based on terrain features, or the like is adopted.

5.5DEM editing

(1) The key points of the DEM editing include contour lines (such as lakes, reservoir shorelines and the like), areas with unclear image textures, areas with complicated ground features and broken landforms, model joint positions and the like.

(2) The DEM should reflect the topographical features, including natural features and artificial features of a certain scale, and should be cut into the ground for populated areas, forest areas. For bridges (road bridges, railroad bridges), elevated roads, etc., DEM shall represent ground, water level, and not deck level.

(3) The level cultivated land should be kept level and no obvious pyramids can appear. The reasonable road and river section elevation according to the scale is ensured, and the elevation difference is not more than 0.5 times of the error of the DEM Gao Chengzhong in principle.

5.6 splicing and cutting of the pictures

(1) Before splicing the pictures, firstly checking the same-name lattice point elevation in the joint overlapping zone, and modifying the worse out-of-limit points according to a three-dimensional model to ensure reasonable data splicing and smooth and natural transition.

The overlapping band of a certain grid should be ensured between the edge data.

(2) And (3) data mosaic is carried out on the basis that the DEM joint is poor and meets the specified requirements, and the numbers of the homonymous grid points Gao Chengqu participating in the joint are used as the grid point elevations after the joint.

(3) After the adjacent DEMs are inlaid, no crack phenomenon occurs, and the elevation values of the overlapped parts are consistent.

(4) And cutting the data according to a specified range to generate a picture DEM.

6. Underwater and near shore integrated Digital Orthophoto Map (DOM)

6.1 production technical Process

The flow of the production technology of the underwater and near-shore integrated Digital Orthophoto Map (DOM) is shown in figure 7.

6.2 DEM for image correction

The DEM grid size and grid point accuracy and range should meet digital orthophoto correction requirements.

6.3 correction of images

And carrying out digital differential correction and image resampling on the image by using the DEM data to generate a digital orthographic image. For image festoon, overhead bridges and the like, a method of locally and properly correcting the DEM can be adopted to correct the image. The orthophoto result is amplified once in the state of printing size, and no drawing phenomenon exists.

The corrected image and the topographic map have no more overlay error than the error in the planar position of the topographic map, and elements with larger projection difference on the image do not undergo overlay inspection, such as buildings, palisades, pipelines and the like.

6.4 image mosaic and cutting

(1) The edge-connecting difference of the same-name images after the correction of the images meets the error requirement in a specified plane.

(2) In principle, images with better image quality are selected during embedding, and the images have the conditions of cloud, shadow and the like and are replaced by adjacent images as much as possible. Note the consistency of stitching during mosaicing, should not produce significant overall visual differences. When the inlaid line is selected, artificial facilities such as large buildings, bridges and the like should be avoided as much as possible.

(3) The digital orthophoto data is cut in a prescribed range, and the storage format is a non-compressed tiff format, while the tfw coordinate information file is stored. When the free-edge image is not full, the blank is filled with white (RGB values 255, 255).

6.5 image color adjustment

The digital orthophoto image should be clear, the texture information is rich, the image between the sheets is kept uniform in tone as much as possible, the contrast is moderate, and the trace left by the image processing cannot be found on the image surface.

The above embodiments are merely preferred embodiments of the present invention, the protection scope of the present invention is not limited thereto, and any simple changes or equivalent substitutions of technical solutions that can be obviously obtained by those skilled in the art within the technical scope of the present invention disclosed in the present invention belong to the protection scope of the present invention.

Claims

1. The method for producing the underwater and near-shore integrated topographic mapping data is characterized by comprising the following steps of:

carrying out unmanned aerial vehicle aerial photogrammetry and photo control measurement on the offshore land, creating a stereoscopic model based on the measurement result, and acquiring the data result of an offshore digital line drawing, the data result of an offshore digital surface model, the data result of an offshore digital elevation model and the data result of an offshore digital orthographic image drawing based on the stereoscopic model to finish mapping of the offshore topography;

carrying out data edge connection and integration processing on underwater topography mapping results and near-shore topography mapping results, simultaneously carrying out repair or complement on blank data at the edge connection, editing the data subjected to edge connection integration processing, and generating an underwater and near-shore integrated digital line drawing, an underwater and near-shore integrated digital surface model, an underwater and near-shore integrated digital elevation model and an underwater and near-shore integrated digital orthographic image;

And integrating the underwater and near-shore integrated digital line drawing, the underwater and near-shore integrated digital surface model, the underwater and near-shore integrated digital elevation model and the underwater and near-shore integrated digital orthographic image to finish data processing of underwater and near-shore integrated topographic mapping.

2. The method for producing integrated underwater and offshore topographic survey and drawing data according to claim 1, wherein the underwater point cloud data acquisition comprises the steps of:

establishing a temporary water level station and acquiring water level data;

the underwater point cloud data acquisition is carried out by adopting a multi-beam sounding system and a single-beam sounding system; the multi-beam sounding system specifically comprises survey line layout, equipment installation and debugging, attitude parameter calibration and full coverage data acquisition, and the single-beam sounding system specifically comprises survey line layout, equipment installation and debugging, dynamic draft measurement and stability experiment and non-full coverage data acquisition;

3. A method of producing integrated underwater and offshore topographic mapping data as set forth in claim 1, wherein said mapping of the offshore topography comprises the steps of:

based on field image control point achievements, unmanned aerial vehicle aerial photography achievements, camera files and the like, an automatic aerial triangulation system is adopted by PAT-AAT, GXP-AAT and Pixel Grid beam method; and performing space three encryption according to the process flows of creating regional catalogues and related files, matching and editing connection points, measuring ground control points, regional network adjustment, encryption point edge grafting of adjacent regions, result inspection and the like, and forming near-shore space three encryption results.

4. A method for producing integrated underwater and offshore topographic map data as claimed in claim 1, wherein said generating integrated underwater and offshore digital line map includes database data editing, specifically comprising:

5. The method for producing integrated underwater and offshore topographic map data of claim 4, wherein said generating an integrated underwater and offshore digital line map further comprises editing graphic data, in particular comprising:

6. A method of producing integrated underwater and near shore topographic mapping data as set forth in claim 1, wherein said generating an integrated underwater and near shore digital surface model includes:

DSM generation, DSM editing, and map splicing and cropping, wherein:

7. A method for producing integrated underwater and near shore topographic survey data according to claim 1, wherein said generating an integrated underwater and near shore digital elevation model comprises:

8. A method for producing integrated underwater and near shore topographic mapping data as set forth in claim 1, wherein said generating an integrated underwater and near shore digital orthophoto map comprises: