CN112634448B - Universal construction method for space grid driven by global discrete point cloud system - Google Patents
Universal construction method for space grid driven by global discrete point cloud system Download PDFInfo
- Publication number
- CN112634448B CN112634448B CN202011542669.5A CN202011542669A CN112634448B CN 112634448 B CN112634448 B CN 112634448B CN 202011542669 A CN202011542669 A CN 202011542669A CN 112634448 B CN112634448 B CN 112634448B
- Authority
- CN
- China
- Prior art keywords
- grid
- points
- point cloud
- global discrete
- discrete point
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000010276 construction Methods 0.000 title claims abstract description 15
- 238000000034 method Methods 0.000 claims abstract description 67
- 238000006243 chemical reaction Methods 0.000 claims description 11
- QNRATNLHPGXHMA-XZHTYLCXSA-N (r)-(6-ethoxyquinolin-4-yl)-[(2s,4s,5r)-5-ethyl-1-azabicyclo[2.2.2]octan-2-yl]methanol;hydrochloride Chemical compound Cl.C([C@H]([C@H](C1)CC)C2)CN1[C@@H]2[C@H](O)C1=CC=NC2=CC=C(OCC)C=C21 QNRATNLHPGXHMA-XZHTYLCXSA-N 0.000 claims description 5
- 238000010586 diagram Methods 0.000 claims description 5
- 230000009466 transformation Effects 0.000 claims description 5
- 230000008569 process Effects 0.000 claims description 3
- 230000007246 mechanism Effects 0.000 abstract description 5
- 238000004458 analytical method Methods 0.000 description 5
- 238000004364 calculation method Methods 0.000 description 5
- 229910003460 diamond Inorganic materials 0.000 description 5
- 239000010432 diamond Substances 0.000 description 5
- 238000004422 calculation algorithm Methods 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- 238000011161 development Methods 0.000 description 3
- 238000007726 management method Methods 0.000 description 3
- 238000012935 Averaging Methods 0.000 description 2
- 238000013523 data management Methods 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000019771 cognition Effects 0.000 description 1
- 230000001149 cognitive effect Effects 0.000 description 1
- 238000010205 computational analysis Methods 0.000 description 1
- 238000013499 data model Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 238000005290 field theory Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000012552 review Methods 0.000 description 1
- 238000012732 spatial analysis Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012800 visualization Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T17/00—Three dimensional [3D] modelling, e.g. data description of 3D objects
- G06T17/05—Geographic models
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T17/00—Three dimensional [3D] modelling, e.g. data description of 3D objects
- G06T17/20—Finite element generation, e.g. wire-frame surface description, tesselation
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T3/00—Geometric image transformations in the plane of the image
- G06T3/06—Topological mapping of higher dimensional structures onto lower dimensional surfaces
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T9/00—Image coding
- G06T9/001—Model-based coding, e.g. wire frame
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/10—Image acquisition modality
- G06T2207/10028—Range image; Depth image; 3D point clouds
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Geometry (AREA)
- Software Systems (AREA)
- Computer Graphics (AREA)
- Remote Sensing (AREA)
- Multimedia (AREA)
- Image Generation (AREA)
- Processing Or Creating Images (AREA)
Abstract
The invention discloses a universal construction method of a space grid driven by a global discrete point cloud system, which comprises the following steps of 1, generating a global discrete point cloud model based on grid points of a spherical quaternary triangular network; step 2, encoding the global discrete point cloud; step 3, converting the codes and the geographic coordinates; step 4, establishing a proximity search rule of the global discrete point cloud system; and 5, generating the global discrete grid integrated code. The invention takes grid points as a core, introduces a global discrete point cloud system, constructs a universal generation method of a global discrete grid and provides a new idea for an interoperation mechanism of the global discrete grid.
Description
Technical Field
The invention relates to a space frame and a coordinate system of a global system, in particular to a universal construction method of a space grid driven by a global discrete point cloud system.
Background
The earth system is physically a manifold space with multiple layers, logically is a nonlinear complex giant system, and a generalized geographic space contains the whole gravity field. Since ancient times, people's cognition and description of geographic space are performed on Euclidean planes through projection, and Euclidean geometry becomes a powerful tool for people to learn the space. Cannot deny that the projection greatly simplifies the space calculation, has achieved great success in the fields of traditional geographic science and engineering, and the map becomes the milestone of human civilization! However, the projection is only suitable for a small-scale space, and from the perspective of the world and the large scale, the projection changes the manifold property of the geographic space, and three problems are brought to the geographic space information: data cracks, inaccurate spatial analysis, difficult data integration and sharing; particularly, the large space-time data has the characteristics of heterogeneousness, heterogeneity, large volume, multiple scales, high dimensionality and space-time composition, and the traditional map model cannot meet the requirements of management, modeling and application of the large geographical space-time data. The global discrete grid system (DGGS) is a preferred scheme for making a digital earth platform space data model by a compatible, automatic and efficient driving machine.
DGGS is an earth-fitted grid of (elliptical) spheres that can be infinitely subdivided without changing shape. The regular hierarchical subdivision structure ensures that grids of different subdivision levels have strict transformation relation, provides a uniform expression mode for the integration of geographic data with random distribution and unequal scales, and the modern matrix theory and the field theory provide a reliable theoretical basis for uniformly describing and expressing complex and diverse geographic phenomena. Therefore, the discrete type, hierarchy and global continuity characteristics of the DGGS not only meet the requirement of a computer on discrete data processing, but also abandon the constraint of map projection, and are expected to fundamentally solve the problems of data cracks, geometric deformation, topology inconsistency and the like of the traditional projection model in global space-time data management and scale operation.
The grid unit shapes of the global discrete grid system mainly comprise three shapes of triangle, quadrangle and hexagon, each grid unit structure has own advantages and disadvantages, and therefore the complexity of corresponding space operation and computational analysis is different. The DGGS is used as a spatial reference system, grid units need to clearly identify the geographic spatial positions of the grid units, and spatial query is facilitated, so that unique indexes must be specified for the grid units, and in the four elements (grid elements, grid points, grid edges and grid centers) for describing the grid units, the grid centers are unique spatial reference points capable of providing systems and unification for all the grid units and are common associated points for establishing relation between objects, data and the grid elements.
The DGGS exhibits different characteristics depending on the initial polyhedron, grid cells, projection and indexing methods. The development of the global discrete grids has more possibility due to the construction of various grid models, but the models have different structures, and the connection and intercommunication among the grids are difficult due to the difference of a grid subdivision form, address code design and an index mechanism in the model construction process. Because the data expression of a single grid unit has limitation in the aspect of multi-field oriented science problems, the realization of the interoperation function between the multi-type discrete grid systems has important research significance. At present, except that the DGGS index conversion method and the "weak dual" relationship between hexagons and triangles belong to the driving research of the transverse direction between different types of grids, all other documents are the research of the longitudinal driving mechanism of a certain type of grids, for example: a diamond logic structure is established on a regular polyhedron, so that a high-efficiency visualization algorithm suitable for various hexagonal grids is realized; adjacent triangular faces of the regular octahedron are combined into a quadrilateral logic structure, and generation algorithms of different hexagonal grids are established; the "diamond" logical structure is also used to organize spatio-temporal data of different mesh types.
The point is the minimum unit for describing the world of objective substances and is the construction basis of the global discrete grid; the grid points are connected to form grid edges, and the field of the grid center forms a grid cell; meanwhile, the lattice points have good symmetry and definite topological characteristics; the spherical lattice points and the neighborhoods thereof form lattice elements, and various grids can be directly generated according to the difference of the neighborhoods.
The global discrete point cloud system is characterized in that the earth surface is divided into point clouds with different scales according to a certain rule in a discrete mode, each point represents a determined position, and meanwhile, the global discrete point cloud system can be associated with the global discrete grid system according to the topological relation of the points.
Disclosure of Invention
The invention provides a universal construction method of a space grid driven by a global discrete point cloud system, which takes grid points as a core, introduces the global discrete point cloud system, constructs a universal generation method of the global discrete grid and provides a new idea for an interoperation mechanism of the global discrete grid.
The technical scheme adopted by the invention is as follows: a universal construction method of a spatial grid driven by a global discrete point cloud system comprises the following steps:
and 5, generating the global discrete grid integrated code.
Further, the step 1 specifically comprises:
generating grid points of a spherical quaternary triangulation network by adopting a projection meridian bisection method or a latitude bisection method; and (4) the relationship between the grid points and the global discrete point cloud model.
Further, when the meridian bisector method is used, a plane α passes through the center O of the spherical surface S in the three-dimensional euclidean space, a point N (0, r) ON the spherical surface is a spherical pole, and ON is perpendicular to the plane α, and a point a ON the plane is obtained according to equation 1 1 (x 1 ,y 1 0) on the sphere x 2 +y 2 +u 2 ＝R 2 A inverse projection coordinate of (a):
in the formula, R =6371393m, and x, y and z are x-axis, y-axis and z-axis coordinates of a three-dimensional space point respectively;
calculating the reciprocal of the coordinate, performing recursion midpoint-taking division according to subdivision levels by taking 0-degree E/W, 90-degree E, 180-degree E/W and 90-degree W meridian projection lines as reference, sequentially connecting all levels of concentric circles, and performing equal division point division on each circle, wherein the formula is shown as follows:
L＝2 N +1 (2)
P＝4M (3)
in the formula, L is the number of concentric circles, and P is the number of points of the M-th (M is more than or equal to 0 and less than or equal to L) circle layer.
Further, when a latitude bisection method is used, regular point clouds are generated on small circular arcs of spherical latitude, and are recursively subdivided according to subdivision levels N to form 2 N+1 +1 small arcs, the number of points divided on each small arc:
P＝4M
further, the step 2 specifically comprises:
the circle layer code L _ A _ N is used as the core of point cloud coding, wherein L refers to a circle layer, the pole is 0, the equator circle is 2N, A refers to the division level of the S-th circle layer from the starting point to the ending point, the division level is-2S + 1-2S, and the south hemisphere and the north hemisphere are distinguished by the signs.
Further, when a global discrete point cloud model is generated by adopting a meridian bisection method, the conversion between the global discrete point cloud model and a plane coordinate adopts a complex polar coordinate form, and the formula is as follows:
wherein R is the earth radius 6371393m; l indicates a ring layer code; a refers to a position code; n indicates the hierarchy of partitions.
Further, when adopting a latitude bisection method, firstly, calculating the Z value of the point according to the circle layer code according to the following formula:
wherein the northern hemisphere is Z N The southern hemisphere is Z S R is the earth radius 6371393m; l indicates a ring layer code; a refers to a location code; n indicates a subdivision level;
calculating the x and y values of the points according to the position codes, as shown in the following formula:
wherein R is the earth radius 6371393m; l indicates a ring layer code; a refers to a location code; n denotes the subdivision level.
Further, the specific process of step 3 is as follows:
when the meridian bisection method is adopted, the conversion of the codes and the geographic coordinates is completed through the following formula:
when adopting a latitude bisection method, the conversion of the codes and the geographic coordinates is completed through the following formula:
in the formula: lon is longitude; lat is latitude; l is a circle layer code; a is a position code; wherein when a =0, lon =0 ° E/W; when the Ap A and the Ap L are 0, lon is east warp; lon =180 ° E/W, when a = L; when A is less than 0, lon is the west meridian.
Further, the step 4 specifically includes:
according to the positive and negative of the subdivision hierarchical code, the adjacent search can be divided into a south hemisphere and a north hemisphere to be respectively carried out; according to the position of the lattice points represented by the codes, the lattice points can be roughly divided into points on the upper diagram limit boundary of 0 DEG E/W, 90 DEG E/W, 180 DEG E/W and 90 DEG W and other positions, and the rule is as follows: the points at non-boundary positions are (L-1,a-1,N), (L-1, a, N), (L, a +1,N), (L +1, a +1, N), (L +1, a, N), (L, a-1,N), respectively; and the points of the corresponding boundary position positions are (L-1, a, N), (L, a +1,N), (L +1, a +1, N), (L +1, a, N), (L-1,a-1,N), (L, a-1,N), respectively.
Further, the step 5 specifically includes:
the hexagonal grid adopts lattice point coding; the triangular grids are coded according to the number and distribution corresponding relation of the points and the grids and the form of controlling an upper triangle and a lower triangle by one grid point, and are distinguished by additional codes of 0 and 1, wherein the extreme points are special conditions, one point controls four triangles, and the additional codes of 0, 1, 2 and 3 are distinguished; when the diamond grid is coded, the divinatory code of '0', '1', '2' and '3' is added to meet the requirement of coding uniqueness. The transformation of the triangular grid and the rhombic grid codes and the coordinates obtains a plurality of grid points of the grid according to the proximity relation of the subordinate grid points, and then the grid points are obtained by adopting the formulas 1 and 4 or the formulas 5 and 6 according to different subdivision methods; the lattice points of the hexagonal grid mesh are the centers of the triangles, and the space coordinate solving method is to position the centers of the triangles.
The invention has the following beneficial effects: the invention provides a new construction method and a new coding form, and introduces lattice points into a global discrete point cloud system. Compared with the traditional global discrete grid, the generation mode of the global discrete point cloud system is simpler, and the algorithm complexity caused by recursion is avoided; meanwhile, by analyzing the grid points of the global discrete grid and the equal-difference circle layer distribution characteristics of the grid elements and utilizing the global discrete point cloud system, the universal generation method of the global discrete grid is realized, and the method has important significance for the development of the interoperation of the global discrete grid system and the management and expression of global geographic information.
Drawings
FIG. 1 is a schematic view of a ball pole projection;
FIG. 2 is a spherical projection of the southern hemisphere;
FIG. 3 is a schematic diagram of a bisection of latitude method;
FIG. 4 is an encoded spiral curve;
FIG. 5 is a schematic view of adjacent dots;
FIG. 6 is a ratio of maximum distance to minimum distance;
FIG. 7a is a distance mean distribution graph of neighboring points based on the 10 th layer projected meridian bisector method;
FIG. 7b is a graph of the distance mean distribution of neighboring points based on the 12 th layer projection meridian bisection method;
FIG. 7c is a distance mean distribution graph of neighboring points based on the 10 th-level latitudinal bisection method;
FIG. 7d is a distance mean distribution graph of neighboring points based on the 12 th layer of latitude bisection method;
FIG. 8a is a triangular mesh encoding;
FIG. 8b is a diamond mesh encoding;
FIG. 8c is a hexagonal grid code;
FIG. 9a is a surface elevation model of Henan province in China generated using point clouds;
FIG. 9b is a surface elevation model of Henan province in China generated using triangular meshes;
FIG. 9c is a surface elevation model of Henan province in China generated using diamond-shaped grids;
fig. 9d is a surface elevation model of chinese henan province generated using hexagonal grids.
Detailed Description
The invention is further described below with reference to the figures and examples.
The invention relates to a universal construction method of a space grid driven by a global discrete point cloud system, which comprises the following steps:
In the construction of the global discrete grid, the three-dimensional grids of 5 kinds of platonic diagrams such as tetrahedron, cube, regular octahedron, regular dodecahedron and regular icosahedron can simulate the earth, wherein the regular octahedron has regular shape and simple structure, and the conversion between the vertex and the longitude and latitude coordinates of the spherical surface is easier. In conclusion, the invention adopts the grid points of the spherical quaternary triangulation network as the basis of the global discrete point cloud system. The generation method can be mainly divided into a projection meridian bisection method and a latitude bisection method, can ensure that projected points are all positioned on the characteristic line (latitude) of the spherical surface, and is simple with the construction method.
1. Meridian bisection method
The plane alpha passes through the sphere S (x) in 3-dimensional Euclidean space 2 +y 2 +u 2 ＝R 2 R =6371393 m), point N (0, R) ON the sphere is the pole, and ON is perpendicular to plane a, as in fig. 1. From the projection of the sphere pole, point A on the plane 1 (x 1 ,y 1 0) on the sphere x 2 +y 2 +u 2 ＝R 2 The inverse projection coordinate of (A) is as shown in formula (1):
in the formula, R =6371393m, and x, y and z are x-axis, y-axis and z-axis coordinates of the three-dimensional space point respectively.
And the projection coordinate of the pole N of the north pole on the plane is infinity, and for calculation convenience, the reciprocal of the projection coordinate of the north hemisphere is solved according to the symmetric characteristics of the south hemisphere and the north hemisphere, and the problem is converted into the projection calculation of the south hemisphere. The spherical pole projection of the spherical surface of the southern hemisphere is shown in FIG. 2, based on the meridian projection lines of 0 degree E/W, 90 degree E, 180 degree E/W and 90 degree W (y =0,0 ≤ x ≤ R, x =0,0 ≤ y ≤ R, y =0,0 ≤ x ≤ R, y =0,0 ≤ x ≤ R), recursively dividing the middle points according to the subdivision levels, sequentially connecting the concentric circles of each level, and equally dividing the points of each circle, wherein the number L of concentric circles (the poles are special concentric circles) and the number P of points of the M (0 ≤ M ≤ L) circle level are as shown in formulas 2 and 3 (the subdivision level is N, taking the southern hemisphere as an example). And finally, performing spherical polar reverse projection on the calculated plane regular point cloud to obtain a global discrete point cloud model.
L＝2 N +1 (2)
P＝4M (3)
2. Method of bisection of latitude
The latitude bisection method directly generates regular point cloud on the spherical latitude small circular arc without projection. Firstly, according to the subdivision level N, recursion subdivision is carried out according to the dichotomy latitude to form 2 N+1 +1 small circular arcs (two poles are special small circular arcs), and the number of points divided on each small circular arc is the same as the above formula (3).
And 2, encoding the global discrete point cloud.
The coding operation of grid units is the core of DGGS, supports the rapid indexing of the spatial data of the whole system and the efficient calculation of application analysis [ review on the research progress of earth subdivision grid ], and the number and distribution of grid points are determined by subdivision rules, so that the connection mode of the grid points and the shape and position of grid elements are influenced, and the method is a theoretical basis for establishing point cloud coding.
According to the characteristics of the equal-difference circle layers of the grid points, the distribution of the equal-difference circle layers is shown in fig. 2 and 3, a circle layer code is introduced as the core of point cloud coding, the specific expression form is L _ A _ N, L refers to the circle layer, the pole is 0, the equator circle is 2 N A denotes the S-th loop layerFrom the starting point to the end point, sequentially-2S + 1-2S, N indicates a subdivision level, and the south hemisphere and the north hemisphere are distinguished by signs. If the layer 2 codes of the northern hemisphere of the layer 2 subdivision are respectively 2_ -1_2;2_0_2;2_1_2; 2_2. The coding organically fuses the hierarchical coding and the integer coordinate and has the characteristic of a one-dimensional spiral curve, as shown in figure 4. The hierarchy of points is ensured, and the encoding operation is convenient. According to the characteristics of the encoded circle layer, for the meridian bisection method, the transformation of the meridian bisection method and the plane coordinate adopts a complex polar coordinate form, the method is shown as formula 4, and the spherical coordinate can be obtained by using the formula (1) after the plane coordinate P is obtained. For the latitude bisection method, the conversion method of the latitude bisection method and the space coordinate is as the formula 5-7, firstly, the Z value of the point is calculated according to the formula 5 according to the circle layer code (the northern hemisphere is Z value) N The southern hemisphere is Z S ) And then calculating the x and y values of the points according to the position codes, as shown in the formula 6-7.
In the formula: r is the earth radius 6371393m; l indicates a ring layer code; a refers to a location code; n denotes the subdivision level.
And 3, converting the codes and the geographic coordinates.
The global discrete point cloud system essentially belongs to a grid model. Unlike vector models, which represent the location of an entity in a coordinate string, grid models represent the location of an entity using code. In order to realize the further application of the discrete point cloud and adapt to the cognitive habits of people, the interconversion (namely decoding) of the codes to the traditional coordinate system is a core key problem which must be solved by the application of the discrete point cloud. The encoding of the invention can realize direct conversion with geographic coordinates. The latitude is mainly determined by the circle layer code, the longitude is mainly determined by the position code, the calculation formula is different according to different generation modes of points, and the longitude bisection method and the latitude bisection method can respectively complete the conversion of the codes and the geographic coordinates according to the formulas 8 and 9.
In the formula: lon is longitude; lat is latitude; l is a circle layer code; a is a position code; wherein when a =0, lon =0 ° E/W,0<a or L, lon is east warp, when a = L, lon =180 ° E/W, when a <0, lon is west warp; north and south latitude are determined by the third part of the code.
And 4, creating a proximity search rule of the global discrete point cloud system.
The adjacent search of lattice points is the basis for supporting the data management of a global discrete point cloud system, and is a core mechanism for realizing spatial operations such as spatial clustering, indexing, dynamic expansion, range query and the like. The codes proposed by the present invention have the characteristic of integer coordinate codes, so that the adjacent search is simple, and the codes can be roughly divided into points on the upper diagram limit boundaries of 0 DEG E/W, 90 DEG E, 180 DEG E/W and 90 DEG W and other points according to the positions of grid points, as shown in FIG. 5.
The adjacent search rule of the grid points of the northern hemisphere is given below (similar to the southern hemisphere, and the description is omitted here).
The geometric feature analysis of the global discrete point cloud is the basis for performing relevant space analysis operations such as geostatistics and the like and generating a multi-grid in a self-adaptive manner, and the uniformity of the points is an important index for judging whether the model is qualified or not. Therefore, the invention carries out relevant experimental analysis on the uniformity of the global discrete point cloud, and because the spherical surface is a highly symmetrical geometric body, the invention selects 1/8 spherical surface (northern hemisphere, east longitude 0-90 degrees) to carry out hierarchical division, measures the uniformity of the point cloud by using the distance mean distribution of points and 6 adjacent points (wherein the adjacent points of poles are 4), and represents the distance deformation condition changing along with the hierarchy according to the ratio delta of the maximum distance to the minimum distance, as shown in formulas 10 and 11 and fig. 6, 7a-7d and 8a-8 c.
In the formula:
the distance mean value of any point P and the adjacent 6 points; r refers to the radius of the earth; α points the latitude angle of P; a longitude angle β points P; alpha is alpha i Pointing pth adjacent latitude angle; beta is a i Pointing P the ith adjacent longitude angle.
The following conclusions can be drawn by analysis: 1) The maximum/minimum distances between all grid points and adjacent points of the two methods are increased along with the subdivision levels, but the overall method is in a convergence trend, wherein the delta values of the latitude bisection method and the meridian bisection method are smaller, and the trend is stable. This means that the higher the hierarchy, the smaller the variation in cell shape. 2) Fig. 7a to 7d show the point cloud neighboring distance mean distribution of the two methods at levels 10 and 12, respectively, which approximately represents three levels of high, medium and low latitude and gradually converges to the extreme point, wherein the uniformity of the latitude averaging method is better than the projection meridian averaging method.
And 5, generating the global discrete grid integrated code.
According to the lattice points and the equal-difference circle layer distribution mode of the lattice elements, the lattice points of the triangular and the rhombic grids are uniform, and the lattice points are the centers of the hexagons, so that the coding of the affiliated lattice points of the lattice elements can be adopted for the lattice elements. The hexagonal grids can be directly coded by adopting grid point codes, the triangles are coded in a mode that an upper triangle and a lower triangle are controlled by one grid point according to the corresponding relation of the number and the distribution of the points and the grids, and are distinguished by additional codes of 0 and 1, wherein the extreme points are special cases, one point controls four triangles and is distinguished by additional codes of 0, 1, 2 and 3, for rhombuses, because the trigram limit boundary can not meet the condition that one rhombus unit belongs to one grid point, the trigram limit codes of 0, 1, 2 and 3 are required to be added when the rhombus grids are coded to meet the requirement of coding uniqueness, and particularly, as shown in fig. 8a to 8 c. The transformation of the triangular and rhombic grid codes and the coordinates obtains a plurality of grid points of the grid according to the adjacent relation of the subordinate grid points, and then the grid points are obtained by adopting the formulas (1), (4) or the formulas (5) and (6) according to different subdivision methods. The lattice points of the hexagonal grid mesh are the centers of the triangles, and the space coordinate solving method mainly comprises the step of positioning the positions of the centers of the triangles, which is not repeated herein.
As shown in fig. 9a to 9d, the surface elevation models of chinese henan province generated by point cloud, triangular mesh, diamond mesh and hexagonal mesh are respectively shown.
The invention introduces a global discrete point cloud system by using grid points, provides a new construction method and a new coding form for supporting the novel global data frame, and compared with the traditional global discrete grid, the generation mode of the global discrete point cloud system is simpler, and the algorithm complexity caused by recursion is avoided. Meanwhile, by analyzing the grid points of the global discrete grid and the equal-difference circle layer distribution characteristics of the grid elements and utilizing the global discrete point cloud system, the universal generation method of the global discrete grid is realized, and the method has important significance for the development of the interoperation of the global discrete grid system and the management and expression of global geographic information.
Claims (8)
1. A universal construction method of a spatial grid driven by a global discrete point cloud system is characterized by comprising the following steps:
step 1, generating a global discrete point cloud model based on grid points of a spherical quaternary triangulation network by adopting a projection meridian bisection method or a latitude bisection method;
when the meridian bisection method is used, a plane alpha passes through the sphere center O of the spherical surface S in the three-dimensional Euclidean space, and a point N on the spherical surface 0 (0, R) is a ball and ON is perpendicular to the plane α, and the point A ON the plane is found according to equation 1 1 (x 1 ,y 1 0) on the sphere x 2 +y 2 +u 2 ＝R 2 A inverse projection coordinate of (a):
in the formula, R =6371393m, and x, y and z are x-axis, y-axis and z-axis coordinates of a three-dimensional space point respectively;
calculating the reciprocal of the coordinate, recursively taking midpoint division according to subdivision levels by taking the meridian projection lines of 0-degree E/W, 90-degree E, 180-degree E/W and 90-degree W as references, sequentially connecting all levels of concentric circles, and equally dividing points of each circle, wherein the reciprocal is shown as the following formula:
L＝2 N +1 (2)
P＝4M (3)
in the formula, L is the number of concentric circles, P is the number of points of the M-th (M is more than or equal to 0 and less than or equal to L) circle layer, and N indicates a subdivision level;
step 2, encoding the global discrete point cloud;
step 3, converting the codes and the geographic coordinates;
step 4, establishing a proximity search rule of the global discrete point cloud system;
and 5, generating the global discrete grid integrated code.
2. The method for constructing a spatial grid driven by global discrete point cloud system according to claim 1, wherein: when using the latitude bisection method, generating regular point clouds on small circular arcs of the spherical latitude, and dividing the point clouds according to the subdivision level NFormed by recursive subdivision according to dichotomy N+1 +1 small arcs, the number of points divided on each small arc:
P＝4M 。
3. the method for universally constructing a spatial grid driven by a global discrete point cloud system according to claim 1, wherein the step 2 specifically comprises:
a circle layer code L _ A _ N is used as a core of point cloud encoding, wherein L refers to a circle layer, a pole is 0, an equator circle is 2N, A refers to a division level which is sequentially from a starting point to an ending point and is-2S + 1-2S, and N refers to a division level and distinguishes south and north hemispheres by signs.
4. The method for constructing a spatial grid driven by global discrete point cloud system according to claim 3, wherein: when a global discrete point cloud model is generated by adopting a meridian bisection method, the conversion between the global discrete point cloud model and a plane coordinate adopts a complex polar coordinate form, and the formula is as follows:
wherein R is the earth radius 6371393m; l indicates a ring layer code; a refers to a position code; n denotes the subdivision level.
5. The method for constructing a spatial grid driven by global discrete point cloud system according to claim 3, wherein: when adopting a latitude bisection method, firstly, calculating the Z value of a point according to the circle layer code according to the following formula:
in the formula, the northern hemisphere is Z N The southern hemisphere is Z S R is the earth radius 6371393m; l indicates a ring layer code; a refers to a location code; n indicates a subdivision level;
calculating the x and y values of the points according to the position codes, as shown in the following formula:
wherein R is the earth radius 6371393m; l indicates a ring layer code; a refers to a position code; n denotes the subdivision level.
6. The method for constructing a spatial grid driven by a global discrete point cloud system according to claim 1, wherein the specific process of step 3 is as follows:
when the meridian bisection method is adopted, the conversion of the codes and the geographic coordinates is completed through the following formula:
when adopting a latitude bisection method, the conversion of the codes and the geographic coordinates is completed through the following formula:
in the formula: lon is longitude; lat is latitude; l is a circle layer code; a is a position code; wherein when a =0, lon =0 ° E/W; when the Ap A and the Ap L are 0, lon is east warp; lon =180 ° E/W, when a = L; when A is less than 0, lon is the west meridian.
7. The method according to claim 1, wherein the step 4 is specifically as follows:
according to the positive and negative of the subdivision hierarchical code, the adjacent search can be divided into a south hemisphere and a north hemisphere to be respectively carried out; according to the position of the lattice points represented by the codes, the lattice points can be roughly divided into points on the upper diagram limit boundary of 0 DEG E/W, 90 DEG E/W, 180 DEG E/W and 90 DEG W and other positions, and the rule is as follows: the points at non-boundary positions are (L-1,a-1,N), (L-1, a, N), (L, a +1,N), (L +1, a +1, N), (L +1, a, N), (L, a-1,N), respectively; and the points of the corresponding boundary positions are (L-1, a, N), (L, a +1,N), (L +1, a +1, N), (L +1, a, N), (L-1,a-1,N), (L, a-1,N), respectively.
8. The method for universally constructing a spatial grid driven by a global discrete point cloud system according to claim 1, wherein the step 5 specifically comprises:
the hexagonal grid adopts lattice point coding;
the triangular grids are coded according to the corresponding relation of the number and the distribution of the points and grids and the form of controlling an upper triangle and a lower triangle by one grid point, and are distinguished by additional codes of '0' and '1', wherein the extreme points are special cases, one point controls four triangles, and the four triangles are distinguished by additional codes of '0', 1 ', 2' and '3';
when the rhombic grids are coded, the divinatory code of '0', '1', '2' and '3' needs to be added to meet the requirement of coding uniqueness;
the transformation of the triangular grid and the rhombic grid codes and the coordinates obtains a plurality of grid points of the grid according to the proximity relation of the subordinate grid points, and then the grid points are obtained by adopting the formulas (1) and (4) or the formulas (5) and (6) according to different subdivision methods; the lattice points of the hexagonal grid mesh are triangular lattice centers, and the space coordinate solving method is to position the triangular lattice centers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011542669.5A CN112634448B (en) | 2020-12-22 | 2020-12-22 | Universal construction method for space grid driven by global discrete point cloud system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011542669.5A CN112634448B (en) | 2020-12-22 | 2020-12-22 | Universal construction method for space grid driven by global discrete point cloud system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112634448A CN112634448A (en) | 2021-04-09 |
| CN112634448B true CN112634448B (en) | 2022-12-30 |
Family
ID=75321829
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011542669.5A Active CN112634448B (en) | 2020-12-22 | 2020-12-22 | Universal construction method for space grid driven by global discrete point cloud system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112634448B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113327328B (en) * | 2021-08-02 | 2021-10-29 | 苏州鼎纳自动化技术有限公司 | Three-dimensional point cloud data compaction method |
| CN113393579B (en) * | 2021-08-17 | 2021-11-12 | 天津云圣智能科技有限责任公司 | Multi-machine cooperative scanning method and device and electronic equipment |
| CN113689561B (en) * | 2021-08-30 | 2023-05-23 | 中国矿业大学(北京) | Method for interoperating different grids of regular icosahedron based on Z curve coding |
| CN113505189B (en) * | 2021-09-07 | 2022-03-04 | 中国电子科技集团公司第二十八研究所 | Planar target rasterization method based on multi-level global grid |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7804498B1 (en) * | 2004-09-15 | 2010-09-28 | Lewis N Graham | Visualization and storage algorithms associated with processing point cloud data |
| CN107229725A (en) * | 2017-06-06 | 2017-10-03 | 南京师范大学 | The fast conversion method that a kind of geographical coordinate is encoded to the discrete grid of spherical triangle |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9881415B2 (en) * | 2008-06-19 | 2018-01-30 | Robert Andrew Palais | Generating point clouds |
| US10115035B2 (en) * | 2015-01-08 | 2018-10-30 | Sungkyunkwan University Foundation For Corporation Collaboration | Vision system and analytical method for planar surface segmentation |
| GB202001839D0 (en) * | 2020-02-11 | 2020-03-25 | V Nova Int Ltd | Use of tiered hierarchical coding for point cloud compression |
-
2020
- 2020-12-22 CN CN202011542669.5A patent/CN112634448B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7804498B1 (en) * | 2004-09-15 | 2010-09-28 | Lewis N Graham | Visualization and storage algorithms associated with processing point cloud data |
| CN107229725A (en) * | 2017-06-06 | 2017-10-03 | 南京师范大学 | The fast conversion method that a kind of geographical coordinate is encoded to the discrete grid of spherical triangle |
Non-Patent Citations (2)
| Title |
|---|
| Multidimensional binary search trees used for associative searching;Jon Louis Bentley;《Communications of the ACM》;19751231;第18卷(第9期);509-517 * |
| 三维空间格网的多尺度整数编码与数据索引方法;赖广陵等;《测绘学报》;20180715(第07期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112634448A (en) | 2021-04-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112634448B (en) | Universal construction method for space grid driven by global discrete point cloud system | |
| CN106898045B (en) | Large-area true three-dimensional geographic scene self-adaptive construction method based on SGOG tiles | |
| Konstantatou et al. | Polarities in structural analysis and design: n-dimensional graphic statics and structural transformations | |
| EP3734469A1 (en) | Central place indexing systems | |
| CN101783023B (en) | Method for exchanging AutoCAD (computer-aided design) graphic block with point map symbol based on path | |
| Otoo et al. | Indexing on spherical surfaces using semi-quadcodes | |
| CN111797093A (en) | Discrete global grid structure generation method and rapid unit positioning method | |
| CN113269870A (en) | Multi-resolution digital terrain integration method based on three-dimensional subdivision grids | |
| CN101964157B (en) | Sphere rhombic grid recursive subdivision method | |
| Tong et al. | Modeling and expression of vector data in the hexagonal discrete global grid system | |
| Liang et al. | Construction of rhombic triacontahedron discrete global grid systems | |
| Zhou et al. | A pole-oriented discrete global grid system: Quaternary quadrangle mesh | |
| CN108875132A (en) | The Topology Optimization Method of stress constraint quasi-truss Continuum Structure under a kind of multi-state | |
| CN107358652A (en) | A kind of Wireless power transmission sphere concentrator Meshing Method based on regular dodecahedron | |
| Zhou et al. | Efficient encoding and decoding algorithm for triangular discrete global grid based on Hybrid Transformation Strategy | |
| Tong et al. | A new effective hexagonal discrete global grid system: Hexagonal quad balanced structure | |
| Dutton | Planetary modelling via hierarchical tessellation | |
| Sahr et al. | The PlanetRisk discrete global grid system | |
| CN114092654A (en) | Digital earth three-dimensional space scene management method compatible with Beidou grid | |
| CN113689561B (en) | Method for interoperating different grids of regular icosahedron based on Z curve coding | |
| Wu et al. | A Review of the Research on Discrete Global Grid Systems in Digital Earth | |
| Wang et al. | Global 3D-Grids Based on Great Circle Arc QTM Sphere Octree and Its Application | |
| CN117689840A (en) | Coding and operation method and device of rhombic icosahedron global discrete grid system | |
| Wang et al. | On constructing the Earth framework model | |
| CN116805455A (en) | Multi-level airspace planning method based on spherical diamond discrete grid |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |