CN102141999A - Method for storing TIN (Titanium Nitride)-DEM (Digital Elevation Model) based on virtual nodes - Google Patents

Abstract

The invention discloses a method for storing a TIN (Titanium Nitride)-DEM (Digital Elevation Model) based on virtual nodes. In the invention, data sources are judged firstly, and then different methods are used according to different data sources. When the data sources are original data, grids are established through the existing algorithm for constructing an irregular triangulation network; then, the size of blocks is determined according to the requirements of a user; and block storage is carried out on the triangulation network by utilizing the method based on the virtual nodes so that the whole region only can be covered by only one network logically. When the data sources are the existing TIN-DEM block products, the data sources are organized into blocks with the size meeting the requirements of the user through preprocessing operations such as segmentation and combination, and then index arrangement and storage are carried out block by block. The method disclosed by the invention has large practical values when applied to TIN-DEM products, can enhance the storage and updating efficiency of a TIN library, can simplify a production flow in the production and update of the DEM with multiple scales, shortens the production cycle and reduces the labor intensity.

Description

A kind of TIN-DEM storage method based on dummy node

Technical field

The invention belongs to computer application field, relate in particular to a kind of TIN-DEM storage means based on dummy node.

Background technology

Digital elevation model (DEM) is more and more important as a kind of special effect of spatial data content in NSDI.In order to satisfy the various demands to large scale basic data collection, extensive dem data usually uses the large scale basic data source and produces with very high precision and resolution.Particularly TIN digital ground elevation model (TIN-DEM) demand is increasing, yet the data of magnanimity make the storage administration to data become increasingly complex, and existing storage means can not satisfy the storage administration to the TIN-DEM data of magnanimity.

Summary of the invention

Problem to be solved by this invention is: a kind of method of TIN ground elevation model data of the storage magnanimity based on dummy node is provided, improves storage and updating efficiency.

Technical scheme provided by the invention is: the storage means of a kind of TIN-DEM based on dummy node may further comprise the steps:

Step 1, the judgment data source, if data source be raw data then enter step 2, if data source is existing TIN-DEM blocks of data then enters step 3;

Step 2 makes up the TIN-DEM net according to raw data, with TIN-DEM net that structure the is good data volume according to user's request or acquiescence, adopts and carries out piece based on the mode of dummy node and divide, and obtains some TIN-DEM blocks of data, enters step 4 then;

Described mode based on dummy node is carried out piece and is divided, be meant and carrying out producing dummy node when piece is divided and adding to divide gained TIN-DEM blocks of data, wherein dummy node is the intersection point that piece is divided used blueline and TIN-DEM net, and this intersection point does not exist in the constructed TIN-DEM net of raw data;

Step 3 is carried out pre-service to the scope and the size of existing TIN-DEM blocks of data, enters step 4 then; Described pretreatment mode is, if the scope of certain TIN-DEM blocks of data and size have surpassed the preset upper limit value, then this TIN-DEM blocks of data is adopted based on the mode of dummy node and carries out the piece cutting; If the piece scope of certain TIN-DEM blocks of data less than the predetermined lower limit value, is then spliced this TIN-DEM blocks of data;

Described mode based on dummy node is carried out the piece cutting, be meant when carrying out the piece cutting, to produce dummy node and add and cut apart gained TIN-DEM blocks of data, wherein dummy node is that piece is cut apart used blueline and the intersection point of being cut apart the TIN-DEM blocks of data, and this intersection point is cut apart in the TIN-DEM blocks of data at quilt and do not existed; Step 4 is carried out the index layout to all TIN-DEM blocks of data, and as requested the TIN-DEM blocks of data is derived or go into library storage.

Characteristics of the present invention: this method can be suitable for the efficient storage of magnanimity TIN digital ground elevation model data.Difference according to data source, by using different cutting apart and processing procedure such as merging based on dummy node, realizing after the storage that logically whole regional one throws the net, is that unit stores and permutation index with the piece in the time of actual storage, has improved storage and updating efficiency.Earlier data storage is earlier imported to database hereof again during concrete the storage, can take into account file user and database user simultaneously, the dirigibility of document retaining storage mode; File and database are consistent, comprise the layout of piece, index of piece or the like.

Description of drawings

Fig. 1 is the embodiment of the invention makes up the TIN-DEM net from raw data a synoptic diagram;

Fig. 2 is the synoptic diagram of the embodiment of the invention to the cutting of TIN-DEM net;

Fig. 3 merges two triangulation network synoptic diagram before in the embodiment of the invention;

Fig. 4 indicates the area schematic that needs reconstruct and optimization in the embodiment of the invention

Fig. 5 merges triangulation network synoptic diagram afterwards in the embodiment of the invention;

Fig. 6 is a piece index synoptic diagram in the embodiment of the invention.

Embodiment

Followingly with reference to Fig. 1-6 and embodiment technical solution of the present invention is described, the performing step of embodiment is as follows:

Step 1, at first judgment data source.The data source of handling is main generally speaking in two ways, and a kind of is original data, and need directly make up TIN this moment from raw data; Another kind is the existing TIN-DEM blocks of data that provides as product, because existing blocks of data range size might not satisfy user's demand just, should cut apart once more or splice this moment data block.If raw data then enters step 2, if existing TIN-DEM blocks of data then enters step 3.

Step 2 is carried out network forming according to raw data, adopts the structure TIN algorithm of prior art to get final product, and the present invention will not give unnecessary details.As Fig. 1 is the TIN-DEM net that builds.Then the TIN-DEM net that structure is good being carried out piece according to the data volume of user's request or acquiescence divides.If block is divided in the intersection point of used blueline and TIN-DEM net, when non-existent dummy node is arranged in the constructed TIN-DEM of the raw data net, this dummy node is joined in the data of existing network forming, in order to avoid it is imperfect to divide the vertex data of gained TIN-DEM blocks of data.As shown in Figure 2, the point of white is empty summit, and the point of black is the point of raw data data centralization, and dotted line is empty limit, enters step 4 then.

Step 3 is carried out pre-service to the scope and the size of existing TIN-DEM blocks of data, and promptly if block scope and size have surpassed the preset upper limit value, then need piece is cut; The if block scope then needs this piece is spliced less than the predetermined lower limit value.

When an existing TIN-DEM blocks of data is carried out cutting operation, consistent with the mode of TIN-DEM net piecemeal in the step 2.Can obtain intersection point with the existing triangulation network along the piece cut-off rule, will non-existent intersection point be added to dummy node in the TIN-DEM blocks of data being cut apart, and note.Like this, cut apart two new pieces of gained the public intersection point that cut-off rule produced is all arranged.

When carrying out the edge fit union operation,, only need judge whether it is same point in the time of edge fit or merging along the block boundary that dummy node is arranged owing to have the existence of dummy node.If when two or more pieces to be combined have a dummy node to be respectively at same that overlaps, this point deletion is got final product.

Embodiment at first finds adjacent two pieces according to coordinate and Given information when splicing, Figure 3 shows that two adjacent blocks: piecemeal A and piecemeal B.Connect two pieces bottom with summit topmost, can obtain the delta-shaped region that need be reconstructed and optimize, promptly be the dash area of Fig. 4.In this zone, be reconstructed and optimize the triangulation network and get final product.Fig. 5 is that frame of broken lines then is a former scope through the triangulation network after handling.Enter step 4 then.

Step 4 is carried out the index layout to all TIN-DEM blocks of data.The character string that time standby " Scale_X_Y " mode that embodiment encodes at index connects is as the filename of piece.Wherein, Scale represents the engineer's scale size of this piece, is exactly 10000 as 1: 1 ten thousand; X represents the row of this piece in this net number (since 0); Y represents the row of this piece in this net number (since 0).As shown in Figure 6, according to from left to right, order is from top to bottom come the index of piece of tissue, from left to right since 0 be row number, from top to bottom since 0 be the row number.Be example with four pieces among the figure, be encoded to 1000_1_0,1000_1_1,1000_0_0,1000_0_1 respectively.Earlier hereof, import database by file then during concrete the storage with the storage of TIN net.

Claims (1)

1. TIN-DEM storage means based on dummy node may further comprise the steps:

Step 1, the judgment data source, if data source be raw data then enter step 2, if data source is existing TIN-DEM blocks of data then enters step 3;

Step 2 makes up the TIN-DEM net according to raw data, with TIN-DEM net that structure the is good data volume according to user's request or acquiescence, adopts and carries out piece based on the mode of dummy node and divide, and obtains some TIN-DEM blocks of data, enters step 4 then;

Described mode based on dummy node is carried out piece and is divided, be meant and carrying out producing dummy node when piece is divided and adding to divide gained TIN-DEM blocks of data, wherein dummy node is the intersection point that piece is divided used blueline and TIN-DEM net, and this intersection point does not exist in the constructed TIN-DEM net of raw data;

Step 3 is carried out pre-service to the scope and the size of existing TIN-DEM blocks of data, enters step 4 then; Described pretreatment mode is, if the scope of certain TIN-DEM blocks of data and size have surpassed the preset upper limit value, then this TIN-DEM blocks of data is adopted based on the mode of dummy node and carries out the piece cutting; If the piece scope of certain TIN-DEM blocks of data less than the predetermined lower limit value, is then spliced this TIN-DEM blocks of data;

Described mode based on dummy node is carried out the piece cutting, be meant when carrying out the piece cutting, to produce dummy node and add and cut apart gained TIN-DEM blocks of data, wherein dummy node is that piece is cut apart used blueline and the intersection point of being cut apart the TIN-DEM blocks of data, and this intersection point is cut apart in the TIN-DEM blocks of data at quilt and do not existed; Step 4 is carried out the index layout to all TIN-DEM blocks of data, and as requested the TIN-DEM blocks of data is derived or go into library storage.

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