Submarine topography six-dimensional grid mapping method

摘要

The present invention discloses a submarine topography six-dimensional grid mapping method, and particularly to a method based on known discrete bathymetric data points. According to the present invention, a submarine topography six-dimensional grid mapping method including X-coordinate, Y-coordinate, water depth, slope, second derivative and measuring time is established, a submarine topography three-dimensional grid on the basis of discrete water depth data and measuring time is formed, and then submarine slope and second derivative of each grid point are calculated and the measuring time is superposed simultaneously, thus forming a submarine topography six-dimensional grid technical method. The present invention comprises a plurality of steps: establishing a submarine topography six-dimensional grid structure and a topography dimension grid, establishing a time dimension grid, establishing a slope dimension grid, and establishing a second derivative dimension grid. The present invention has the advantages of being accurate in mapping data, convenient to operate, wide in application range, little in influence of natural weather and the like in the process of Chinese coastal mapping and marine demarcation.

主权项

1. A computer implemented submarine topography six-dimensional grid mapping method executed on a processor, comprising the following steps of:
(1) establishing submarine topography six-dimensional grid structure by obtaining discrete X-coordinate, Y-coordinate, water depth value by a submarine coordinate numerical value measuring instrument located under water, and measuring time values by a clock; transmitting measured numerical values to a six-dimensional grid structure processing device through the submarine coordinate numerical value measuring instrument, wherein the processing device divides submarine coordinate measured data points into two parts, one part is a head structure “Head” for describing and storing integral information of the grid structure, and the other part is a data setGRID⁡(i,j)={grid⁡(i,j)i=1,Mj=1,N}for storing the grid; wherein
a head structure “Head” consists of eight lines: a first line refers to mark “Mark”; a second line refers to M and N, representing the line quantity and row quantity of the grid; a third line refers to xmin and xmax, representing the minimum and maximum values of the X-coordinate of the grid; a fourth line refers to ymin and ymax, representing the minimum and maximum values of the Y-coordinate of the grid; a fifth line refers to zmin and zmax, representing the minimum and maximum values of the topography of the grid; a sixth line refers to tmin and tmax, representing the minimum and maximum values of the time of the grid; a seventh line refers to slpmin and slpmax, representing the minimum and maximum values of the slope of the grid; and an eighth line refers to secmin and secmax, representing the minimum and maximum values of the second derivative of the grid; storing the data setGRID⁡(i,j)={grid⁡(i,j)i=1,Mj=1,N}according to the space sequence of the data points in a two-dimensional orthographic projection plane, wherein each data point grid(i,j) comprises four parameters which are respectively water depth value dep(i,j), time value time(i,j), slope value slp(i,j) and second derivative value sec(i,j), and the X-coordinate value x(i,j) and the Y-coordinate y(i,j) value of the point are calculated according to the line number i and row number j thereof, wherein:
x(i,j)=xmin+(i−1)×xmean; xmean=(xmax−xmin)/(N−1); y(i,j)=ymin+(j−1)×ymean; ymean=(ymax−ymin)/(M−1); (2) establishing of topography dimension grid in the six-dimensional grid by employing an inverse distance weighting method to establish the topography dimension grid DEP(i,j):dep(i,j)=[∑k=1n⁢wk⁢zk]/∑k=1n⁢wk;wk=1/dk2;dk=(x(i,j)-xk)2+(y(i,j)-yk)2 where Z={zk}k=1,n refers to a discrete water depth set, xk refers to the X-coordinate value of a discrete water depth data point, and yk refers to the Y-coordinate value of the discrete water depth data point, wherein each discrete water depth data point comprises water depth value zk, X-coordinate value xk, Y-coordinate value yk and measuring time tk, which are external input variables; wk refers to the weighted value of the discrete water depth data point, which is a calculation variable; the above-mentioned water depth value zk, X-coordinate value xk and Y-coordinate value yk are determined by the measuring of the submarine coordinate numerical value measuring instrument, and the time tk is determined by the clock; if topographical change is strongly correlated to the time, establishing the topography dimension grid DEP(i,j) according to the time value tk; that is, when tk=T, the water depth zk participates in the calculation, T refers to the data measuring time, which is an external variable; if the topographical change is weekly correlated to the time, the time value tk does not participate in the calculation; in the foregoing two cases that the topographical change is strongly correlated to the time and the topographical change is weekly correlated to the time, all the water depth data zk participating in calculation meets a distance rule that dk≦r, wherein r refers to a measuring radius; traversing the topography dimension grid DEP(i,j), obtaining the minimum water depth value zmin and the maximum water depth value zmax and storing into the structure Head; (3) establishing of time dimension grid in the six-dimensional grid by determining the time dimension grid TIME(i,j) by the measuring time tk of the water depth data set Z={zk}k=1,n and establishing the time dimension grid TIME(i,j) by two manners: if the time dimension grid TIME(i,j) is synchronously established with the topography dimension grid DEP(i,j) when establishing the topography dimension grid DEP(i,j) directly assigning the measuring time tk of the discrete data set Z={zk}k=1,n to a time grid point time(i,j); that is, when zk participates in establishing the topography dimension grid DEP(i,j, time(i,j)=tk; and the data measuring time on the same spatial position is consistent; if the time dimension grid TIME(i,j) is established after the topography grid DEP(i,j) is established, determining the measuring time tk through an external variable, determining the measured numerical values in a mapping region polygon “Poly” within a fixed time t through continuously measuring the water depth value, endowing a time attribute to the mapping polygon “Poly”, then carrying out polygon partitioning on the entire mapping region according to the measuring time to form a mapping polygon set Poly={pk}k=1, n, wherein each polygon pk corresponds to one measuring time tk; and then establishing the time dimension grid TIME(i,j); cycling the mapping polygon Poly={pk}k=1,n, taking the polygon pk out in sequence, then cycling two-dimensional topography grid DEP(i,j), wherein space and position matching is carried out between each water depth value dep(i,j) measured and pk; that is, when the water depth grid point dep(i,j) is located in the mapping polygon pk, time(i,j)=tk; employing the foregoing method to traverse the mapping polygon data set Poly={pk}k=1,n, thus being capable of establishing the time dimension grid TIME(i,j); traversing the time dimension grid TIME(i,j), obtaining the minimum time value tmin and the maximum time value tmax and storing into the structure Head; (4) establishing of slope dimension grid in the six-dimensional grid by establishing the slope dimension grid SLP(i,j) based on the topography dimension grid DEP(i,j); traversing the slope dimension grid SLP(i,j) takes the grid point slp(i,j) as a center and takes a square R1 using twice stepslp as a side length to encircle a calculating point slp(i,j), and water depth points dep(i,j) falling within the square R1 participate in slope calculation to calculate the maximum slope slp max(i,j) and the mean slope slpmean(i,j) of each grid point slp(i,j); the calculating formula of the slope slp(I,J) between each point dep(I,J) and the central point dep(i,j) is:
slp(I,J)=arctan [(dep(i,J)−dep(i,j))/dis]dis=√{square root over ((x(i,j)−x(i,J))2+(y(i,j)−y(I,J))2)}{square root over ((x(i,j)−x(i,J))2+(y(i,j)−y(I,J))2)}{square root over ((x(i,j)−x(i,J))2+(y(i,j)−y(I,J))2)}{square root over ((x(i,j)−x(i,J))2+(y(i,j)−y(I,J))2)} where, [x(I,J), y(I,j)] and [x(I,J), y(I,J)] are respectively the coordinate values of the water depth points dep(i,j) and dep(I,J), and the slope dimension grid SLP(i,j) can be obtained through employing the foregoing method to traverse the topography dimension grid DEP(i,j); traversing the slope dimension grid SLP(i,j), obtaining the minimum slope value slpmin and the maximum slope value slpmax, and storing into the structure Head; (5) establishing of second derivative dimension grid in the six-dimensional grid by obtaining the second derivative dimension grid SEC(i,j) according to the same method in step (4) by taking the slope dimension grid SLP(i,j) calculated in step (4) as an input variable to replace the topography dimension grid DEP(i,j), wherein the calculating method is as follows: taking the position of the calculating point sec(i,j) as a center and taking a square R2 using twice stepsec as a side length to encircle the calculating point sec(i,j), and slope points slp(I,J) falling within the square R2 participate in second derivative calculation, wherein all the slope points slp(I,J) within the square R2 participate in the second derivative calculation, and the calculating formula of the second derivative sec(I,J) between each point slp(I,J) and the central point slp(i,j) is:
sec(I,J)=arctan [(slp(I,J)−slp(i,j))/dis]dis=√{square root over ((x(i,j)−x(I,J))2+(y(i,j)−y(I,J))2)}{square root over ((x(i,j)−x(I,J))2+(y(i,j)−y(I,J))2)}{square root over ((x(i,j)−x(I,J))2+(y(i,j)−y(I,J))2)}{square root over ((x(i,j)−x(I,J))2+(y(i,j)−y(I,J))2)} where, [x(i,j), y(i,j)] and [x(I,J), y(I,J)] are respectively the coordinate values of the slope points slp(i,j) and slp(I,J), and the second derivative dimension grid SEC(i,j) can be obtained through employing the method to traverse the slope dimension grid SLP(i,j); traversing the second derivative dimension grid SEC(i,j), obtaining the minimum second derivative value secmin and the maximum second derivative value secmax, and storing into the structure Head.