A method for collecting surface elements based on curve fitting and interpolation

Abstract

The application discloses a kind of surface element collection methods based on curve fitting and interpolation, mainly solve the existing surface covering surface element data collection mainly by artificial collection surface element path both sides boundary point to constitute surface element, collection efficiency is lower, it is difficult to meet the rapidly growing geographic information data demand technical problem.By collecting the end point and inflection point of one side of surface element collection path trajectory as collection node, the coordinate value of the calculation node on the other side of surface element collection path is calculated by trigonometric function, and curve fitting and curve interpolation are carried out on the collected collection node and calculation node, so that the collected surface element trajectory is more consistent with the actual surface element trajectory, so that only one side of surface element trajectory needs to be collected, the trajectory graph of both sides of surface element can be obtained, and the collection efficiency is greatly improved.

Description

Technical Field

[0001] This invention relates to a method for acquiring surface features, specifically a method for acquiring surface features based on curve fitting and interpolation. Background Technology

[0002] With the advancement of social economy and science and technology, computer technology has been widely applied; among them, geographic information technology has also developed along with computer technology. The application of Geographic Information System (GIS) is becoming more and more widespread and diverse, and the requirements for the timeliness of geographic information data are becoming higher and higher. The underlying vector data required by GIS mainly comes from the land cover element data of basic geographic information. This requires faster and more efficient land cover element data acquisition methods to meet the rapidly growing demand for geographic information data.

[0003] Although there has been some progress and breakthroughs in the intelligent interpretation of remote sensing images in recent years, the actual acquisition results cannot meet production needs due to factors such as different image resolutions, image sources, and image acquisition times. Acquisition still mainly relies on a large amount of manual work.

[0004] Existing land cover feature data collection mainly involves manually collecting points on both sides of the feature path to form the feature, which is inefficient and cannot meet the rapidly growing demand for geographic information data. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problem that existing land cover feature data collection mainly relies on manually collecting points on both sides of the feature path to form the feature, which has low collection efficiency and is difficult to meet the rapidly growing demand for geographic information data. In response, this invention provides a feature collection method based on curve fitting and interpolation.

[0006] The technical solution adopted in this invention is: A method for acquiring surface features based on curve fitting and interpolation is characterized by the following steps: Step 1: Measure the distance between any two points at the beginning of the surface feature acquisition path as the initial width of the surface feature; Step 2: Draw the surface features; Step 2.1: Take the endpoint on one side of the starting end of the surface feature acquisition path as the initial acquisition node and obtain the coordinate value of that point; Step 2.2: Proceed along the trajectory on one side of the surface feature acquisition path, collect the inflection points along the direction of the trajectory as the next acquisition node, and obtain the coordinate values ​​of the acquisition node. Step 3, Construction Surface Elements; Step 3.1: Trigonometric function calculation. According to the acquisition order of the acquisition nodes, calculate the coordinate values ​​of the nodes at the corresponding positions on the other side of the surface feature acquisition path for all currently acquired acquisition nodes. Step 3.2: Curve fitting; Curve fitting is performed on the obtained acquisition nodes and calculation nodes based on their coordinate values. Step 3.3: Curve interpolation; Interpolate intermediate nodes between adjacent acquisition nodes and between adjacent calculation nodes on the curve fitting trajectory of acquisition nodes and curve fitting trajectory of calculation nodes, respectively. Step 3.4: Complete the construction of the current face elements; Step 4: Based on the degree of matching between the currently constructed surface features and the actual surface features' trajectories, determine whether it is necessary to adjust the width of the surface features at the trajectory inflection points. If yes, adjust the width based on the initial width and return to Step 3. If no, return to Step 2.2, collect the next inflection point in the forward direction of the surface feature collection path trajectory, until the end point of the surface feature collection path trajectory is collected, and obtain the overall surface feature construction. Step 5: Determine whether the overall effect of the surface features collected from the endpoint to the end point meets the requirements; if not, return to step 2 until the overall effect of the surface features meets the requirements; if yes, perform surface feature topology. Step 6: Display the surface features after topology to complete the surface feature acquisition.

[0007] Furthermore, in step 3.1, the distance between any acquisition node and its corresponding computing node is defined as D. n The coordinates of any acquisition node are (X... n Y n The coordinates of any computed node are (X... 1 n Y 1 n ), where n is 1, 2, 3, ..., N; Step 3.1 specifically includes the following steps: Step 3.1.1: Calculate the angle α between the line connecting adjacent acquisition nodes and the positive Y-axis. n ; α n =arctan ; In the formula, X n+1 and Y n+1 These are the x and y coordinates of the next data acquisition node, respectively. Step 3.1.2: Calculate the coordinates (X) of the calculation nodes. 1 n Y 1n ); X 1 n =X n +D n ×sin(α n + ); Y 1 n =Y n +D n ×cos(α) n + ).

[0008] Furthermore, step 3.2 specifically includes the following steps: Step 3.2.1: Based on the collected node coordinates and the calculated node coordinates, obtain the collection node set [(X1,Y1), (X2,Y2), ..., (X...]. n ,Y n )] and computation node set [(X 1 1, Y 1 1) (X) 1 2, Y 1 2), ..., (X) 1 n Y 1 n )]; Step 3.2.2: Obtain the fitting model y for the data acquisition nodes based on the data acquisition node set and the computation node set respectively. I =f(x,e); and compute the node fitting model y. J =f(x,h); In the formula, e and h are the parameters to be determined; Step 3.2.3: Perform curve fitting on the obtained acquisition nodes and calculation nodes according to the acquisition node fitting model and the calculation node fitting model respectively.

[0009] Further step 3.3 specifically includes the following steps: Step 3.3.1: Obtain the distance between two adjacent acquisition nodes and two adjacent calculation nodes; Step 3.3.2: Based on the fitting function of the acquisition node and the distance between two adjacent acquisition nodes, and the fitting function of the calculation node and the distance between two adjacent calculation nodes, the interpolation formulas for the acquisition node and the calculation node are obtained respectively. The interpolation formula for the data acquisition node is: ; The interpolation formula for calculating nodes is: ; In the formula: ; ; , These are the x-coordinate and y-coordinate values ​​of the data collection node, respectively. , These are the x and y coordinates of the intermediate node during interpolation, respectively. , These represent the x-coordinate and y-coordinate intervals of the data acquisition nodes, respectively. ; ; , These are the x-coordinate and y-coordinate values ​​of the calculated node, respectively. , These are the x and y coordinates of the intermediate node during interpolation, respectively. , These represent the x-coordinate and y-coordinate intervals of the calculated nodes, respectively. The coordinates of the nodes collected before the interpolated intermediate node; The coordinates of the nodes collected after the interpolated intermediate node; To pass The calculated coordinates of the computation nodes; To pass The calculated coordinates of the computation node; Step 3.3.3: Based on the interpolation formulas of the acquisition nodes and the calculation nodes, interpolate intermediate nodes between two adjacent acquisition nodes and two adjacent calculation nodes respectively.

[0010] Furthermore, in step 1, the initial width is defined as d; In step 4, the modification of the width of the surface feature at the trajectory inflection point specifically involves: The adjustment step size L is calculated based on the initial width, where L = 0.1d; or a custom adjustment step size L can be defined. In step 3.1.2, based on the adjustment step size L, the adjusted distance D between the acquisition node and its corresponding computing node is obtained on the basis of the initial width. n =d ML; In the formula: M is the number of adjustments, and M takes values ​​of 0, 1, 2, 3, ..., m.

[0011] Furthermore, in step 5, by comparing with DOM imagery or DEM / DSM data, it is determined whether the overall effect of the surface features collected to the endpoint meets the requirements.

[0012] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses the endpoints and trajectory inflection points on one side of the surface feature acquisition path as acquisition nodes, and calculates the coordinates of the calculation nodes on the other side of the surface feature acquisition path using trigonometric functions. It also performs curve fitting and curve interpolation on both sides of the surface feature acquisition path, thereby achieving the goal of completing the entire surface feature acquisition work by only acquiring one side of the surface feature acquisition path. This reduces the workload of manual acquisition, improves acquisition efficiency, meets the rapidly growing demand for geographic information data, and ensures accurate acquisition of surface feature boundaries. Attached Figure Description

[0013] Figure 1 This is a flowchart of an embodiment of a surface feature acquisition method based on curve fitting and interpolation according to the present invention; Figure 2 This is a schematic diagram of the principle of surface feature construction in a surface feature acquisition method based on curve fitting and interpolation according to the present invention. Detailed Implementation

[0014] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0015] like Figure 1 As shown, this invention discloses a method for acquiring surface features based on curve fitting and interpolation. The objects acquired include various surface features of land cover, such as roads, ditches, and rivers. The method is implemented according to the following steps: Step 1: Measure the distance between any two points at the beginning of the surface feature acquisition path as the initial width of the surface feature; define the initial width as d. Specifically, modifying the surface feature width at the trajectory inflection point involves calculating the adjustment step size L based on the initial width, where L = 0.1d, or a custom adjustment step size L. By setting the adjustment step size, the magnitude of width modification can be controlled, allowing the surface feature width to be adjusted to a smaller error range with fewer adjustments. The initial width should be close to the actual width at the beginning of the surface feature to reduce adjustments at this point. A larger difference is also acceptable, although the calculated adjustment step size will be smaller, requiring more adjustments, but resulting in greater accuracy. Furthermore, based on the actual situation, it is possible to select whether to topologically reconstruct the surface and remove boundary features that exceed the permitted range; Step 2: Draw the surface features; Step 2.1: The endpoint on one side of the starting end of the surface feature acquisition path is used as the initial acquisition node (e.g., ...). Figure 2 Find point A in the map and obtain its coordinates. Step 2.2: Proceed along the trajectory on one side of the surface feature acquisition path, and acquire the inflection points along the direction of this trajectory as the next acquisition node (e.g., ...). Figure 2 (Point B or point C in the data), and obtain the coordinate value of the data acquisition node; Step 3, Construction Surface Elements; Step 3.1: Calculate the coordinates of all currently acquired nodes at their corresponding positions on the other side of the surface feature acquisition path, according to the acquisition order of the acquisition nodes (e.g., ...). Figure 2 A in ‵ B ‵ Or C ‵ ); Define the distance between any data acquisition node and its corresponding computing node as D. n Based on the adjustment step size L, the distance D between the adjusted acquisition node and its corresponding computing node is obtained on the basis of the initial width. n =d ML; where: M is the number of adjustments, and M takes values ​​of 0, 1, 2, 3, ..., m; by increasing or decreasing a certain value based on the initial width, adjustments can be made in real time according to the road width during the acquisition process, improving the accuracy of surface feature acquisition; the coordinates of any acquisition node are (X... n Y n The coordinates of any computed node are (X... 1 n Y 1 n ), where n is 1, 2, 3, ..., N; the coordinates of the first collected node are (X1, Y1), corresponding to Figure 2 Point A in the diagram; the corresponding coordinates of the first calculation node are (X... 1 1, Y 1 1), corresponding Figure 2 A in ‵ Point; and so on, (X2, Y2) corresponds to Figure 2 Point B in (X) 1 2, Y 1 2) Corresponding Figure 2 B in ‵ point; Step 3.1.1: Calculate the angle α between the direction of the surface feature acquisition path and the positive Y-axis at the first acquired acquisition node. n ; α n =arctan ; In the formula, X n+1 and Y n+1 These are the x and y coordinates of the next data acquisition node, respectively. Step 3.1.2: Calculate the coordinates of the nodes (X). 1 n Y 1 n ); X 1 n =X n +Dn ×sin(α n + ); Y 1 n =Y n +D n ×cos(α) n + ); Step 3.2: Curve fitting. Since the data acquisition nodes are displayed as polylines, while the actual ground surface is generally a continuous and gradual change, the data acquisition nodes are fitted with curves to better match the actual ground surface. Curve fitting is performed on the obtained acquisition nodes and calculation nodes based on their coordinate values. Step 3.2.1: Based on the collected node coordinates and the calculated node coordinates, obtain the collection node set [(X1,Y1), (X2,Y2), ..., (X...]. n ,Y n )] and computation node set [(X 1 1, Y 1 1) (X) 1 2, Y 1 2), ..., (X) 1 n Y 1 n )]; Step 3.2.2: Obtain the fitting model y for the data acquisition nodes based on the data acquisition node set and the computation node set respectively. I =f(x,e); and compute the node fitting model y. J =f(x,h); In the formula, e and h are the parameters to be determined; Step 3.2.3: Perform curve fitting on the obtained acquisition nodes and calculation nodes according to the fitting functions of the acquisition nodes and calculation nodes, respectively; Step 3.3 specifically includes the following steps: Step 3.3.1: Obtain the distance between two adjacent acquisition nodes and two adjacent calculation nodes; Step 3.3.2: Based on the fitting function of the acquisition node and the distance between two adjacent acquisition nodes, and the fitting function of the calculation node and the distance between two adjacent calculation nodes, the interpolation formulas for the acquisition node and the calculation node are obtained respectively. The interpolation formula for the data acquisition node is: ; The interpolation formula for calculating nodes is: ; In the formula: ; ; , These are the x-coordinate and y-coordinate values ​​of the data collection node, respectively. , These are the x and y coordinates of the intermediate node during interpolation, respectively. , These represent the x-coordinate and y-coordinate intervals of the data acquisition nodes, respectively. ; ; , These are the x-coordinate and y-coordinate values ​​of the calculated node, respectively. , These are the x and y coordinates of the intermediate node during interpolation, respectively. , These represent the x-coordinate and y-coordinate intervals of the calculated nodes, respectively. The coordinates of the nodes collected before the interpolated intermediate node; The coordinates of the nodes collected after the interpolated intermediate node; To pass The calculated coordinates of the computation node; To pass The calculated coordinates of the computation node; Step 3.3.3: Based on the interpolation formulas of the acquisition nodes and the calculation nodes, interpolate intermediate nodes between two adjacent acquisition nodes and between two adjacent calculation nodes respectively. like Figure 2 Points R, Q, P, N, J, L, and K are all intermediate nodes interpolated on the fitting curve of the acquisition node, and points S, T, U, V, W, X, Y, and Z are all intermediate nodes interpolated on the fitting curve of the calculation node. Step 3.4: Complete the construction of the current face elements; Step 4: Based on the degree of matching between the currently constructed surface features and the actual surface features' trajectories, determine whether it is necessary to adjust the width of the surface features at the trajectory inflection points. If yes, adjust the width based on the initial width and return to Step 3. If no, return to Step 2.2, collect the next inflection point in the forward direction of the surface feature collection path trajectory, until the end point of the surface feature collection path trajectory is collected, and obtain the overall surface feature construction. Step 5: By comparing with DOM (Digital Orthophoto Map) or DEM (Digital Elevation Model) / DSM (Digital Surface Model) data, determine whether the overall effect of the surface features collected from the endpoint to the end point meets the requirements (i.e., determine the matching deviation between the completed surface feature trajectory and the actual surface feature trajectory); if not, return to step 2 until the overall effect of the surface features meets the requirements; if yes, perform surface feature topology. Step 6: Display the surface features after topology to complete the surface feature acquisition.

Claims

1. A method for acquiring surface features based on curve fitting and interpolation, wherein the acquired objects are various surface features of land cover, including roads, ditches, and rivers, characterized in that, The specific steps are as follows: Step 1: Measure the distance between any two points at the beginning of the surface feature acquisition path as the initial width of the surface feature; Step 2: Draw the surface features; Step 2.1: Take the endpoint on one side of the starting end of the surface feature acquisition path as the initial acquisition node and obtain the coordinate value of that point; Step 2.2: Proceed along the trajectory on one side of the surface feature acquisition path, collect the inflection points along the direction of the trajectory as the next acquisition node, and obtain the coordinate values ​​of the acquisition node. Step 3, Construction surface elements; Step 3.1: Trigonometric function calculation. According to the acquisition order of the acquisition nodes, calculate the coordinate values ​​of the nodes at the corresponding positions on the other side of the surface feature acquisition path for all currently acquired acquisition nodes. Step 3.2: Curve fitting; Curve fitting is performed on the obtained acquisition nodes and calculation nodes based on their coordinate values. Step 3.3: Curve interpolation; Interpolate intermediate nodes between adjacent acquisition nodes and between adjacent calculation nodes on the curve fitting trajectory of acquisition nodes and curve fitting trajectory of calculation nodes, respectively. Step 3.4: Complete the construction of the current face elements; Step 4: Based on the degree of matching between the currently constructed surface features and the actual surface features' trajectories, determine whether it is necessary to adjust the width of the surface features at the trajectory inflection points. If yes, adjust the width based on the initial width and return to step 3; if no, return to step 2.2, collect the next inflection point in the direction of the surface feature collection path trajectory, until the end of the surface feature collection path trajectory is collected, and obtain the overall structure of the surface feature. Step 5: By comparing with DOM imagery or DEM / DSM data, determine whether the overall effect of the collected polygon features from the endpoint to the end point meets the requirements; if not, return to step 2 until the overall effect of the polygon features meets the requirements; if yes, perform polygon feature topology. Step 6: Display the surface features after topology to complete the surface feature acquisition.

2. The method for acquiring surface features based on curve fitting and interpolation according to claim 1, characterized in that: In step 3.1, the distance between any acquisition node and its corresponding computing node is defined as D. n The coordinates of any acquisition node are (X... n Y n The coordinates of any computed node are (X... 1 n Y 1 n ), where n is 1, 2, 3, ..., N; Step 3.1 specifically includes the following steps: Step 3.1.1: Calculate the angle α between the line connecting adjacent acquisition nodes and the positive Y-axis. n ; α n =arctan ; In the formula, X n+1 and Y n+1 These are the x and y coordinates of the next data acquisition node, respectively. Step 3.1.2: Calculate the coordinates (X) of the calculation nodes. 1 n Y 1 n ); X 1 n =X n +D n ×sin(α) n + ); Y 1 n =Y n +D n ×cos(α n + )。 3. The method for acquiring surface features based on curve fitting and interpolation according to claim 2, characterized in that, Step 3.2 specifically includes the following steps: Step 3.2.1: Based on the collected node coordinates and the calculated node coordinates, obtain the collection node set [(X1,Y1), (X2,Y2), ..., (X...]. n ,Y n )] and computation node set [(X 1 1, Y 1 1) (X) 1 2, Y 1 2), ..., (X) 1 n Y 1 n )]; Step 3.2.2: Obtain the fitting model y for the data acquisition nodes based on the data acquisition node set and the computation node set respectively. I =f(x,e); and compute the node fitting model y. J =f(x,h); In the formula, e and h are the parameters to be determined; Step 3.2.3: Perform curve fitting on the obtained acquisition nodes and calculation nodes according to the acquisition node fitting model and the calculation node fitting model respectively.

4. The method for acquiring surface features based on curve fitting and interpolation according to claim 3, characterized in that, Step 3.3 specifically includes the following steps: Step 3.3.1: Obtain the distance between two adjacent acquisition nodes and two adjacent calculation nodes; Step 3.3.2: Based on the fitting function of the acquisition node and the distance between two adjacent acquisition nodes, and the fitting function of the calculation node and the distance between two adjacent calculation nodes, the interpolation formulas for the acquisition node and the calculation node are obtained respectively. The interpolation formula for the data acquisition node is: ; The interpolation formula for calculating nodes is: ; In the formula: ; ; , These are the x-coordinate and y-coordinate values ​​of the data collection node, respectively. , These are the x and y coordinates of the intermediate node during interpolation, respectively. , These represent the x-coordinate and y-coordinate intervals of the data acquisition nodes, respectively. ; ; , These are the x-coordinate and y-coordinate values ​​of the calculated node, respectively. , These are the x and y coordinates of the intermediate node during interpolation, respectively. , These represent the x-coordinate and y-coordinate intervals of the calculated nodes, respectively. The coordinates of the nodes collected before the interpolated intermediate node; The coordinates of the nodes collected after the interpolated intermediate node; To pass The calculated coordinates of the computation nodes; To pass The calculated coordinates of the computation nodes; Step 3.3.3: Based on the interpolation formulas of the acquisition nodes and the calculation nodes, interpolate intermediate nodes between two adjacent acquisition nodes and two adjacent calculation nodes respectively.

5. The method for acquiring surface features based on curve fitting and interpolation according to claim 4, characterized in that: In step 1, the initial width is defined as d; In step 4, the modification of the width of the surface feature at the trajectory inflection point specifically involves: The adjustment step size L is calculated based on the initial width, where L = 0.1d; or a custom adjustment step size L can be defined. In step 3.1.2, based on the adjustment step size L, the adjusted distance D between the acquisition node and its corresponding computing node is obtained on the basis of the initial width. n =d ML; In the formula: M is the number of adjustments, and M takes values ​​of 0, 1, 2, 3, ..., m.

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