1、International Standard INTERNATIONAL ORGANIZATION FOR STANDARDIZATIONWIEYHAPOHAR OPrAHM3Al - maximum block length, in words: one-word integer number. 4.2 Subsequent data blocks 4.2.1 Contents Subsequent blocks of data contain geometrical information. Each block contains complete numerical representa
2、tion of one shipline and consists of four (4) records. - one (1) alphanumeric line identifier; - three (3) projections of the line on orthogonal planes. 4.2.2 Layout The layout of a block is the following: . 4.2.2.1 Record 1 IDENT: line identifier up to eight (8) alphanumeric characters; L: line typ
3、e parameter (integer). The line type parameter takes the following values: L = 1 for a Z-dimensional line; L = 2 for a 3-dimensional line contained in a non- orthogonal plane; L = 3 for an arbitrary 3-dimensional line. 4.2.2.2 Record 2 C: projection plane indicator (integer) ; S: distance from the o
4、rigin of the axis systems of or- thogonal plane defining 2-dimensional line, in millimetres (real number) ; When L = 2 or L = 3, S = 0. N : number of points on the projection of the line (integer); P(1) coordinates of the first point, in millimetres (real V(1) number) ; PS(1) VW) not used for defini
5、tion of the line geometry; P(2) coordinates of the second point, in millimetres (real V(2) number) ; PS(2) VS(2) . . . P(N) V(N) coordinates of the centre of the circular arc in the first segment, in millimetres (real number); coordinates of the Nfh point, in millimetres (real number) ; PS(N) coordi
6、nates of the centre of the circular arc in the VS(N) (N - 1 Ith segment, in millimetres (real number). Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 7838-1984 (E) 4
7、2.2.3 Records 3 and 4 5.1 To write a record to the file: Record 3 and record 4 have similar layouts to record 2. PUTLIN (IDENT, L, C, S, N, P, V, PS, VS) where 4.2.2.4 Specifications in common IDENT is a character field; The length of a record is 4 X (N + 311 words. L is an integer number; When L =
8、 1, records 3 and 4 of a data block are present but have no significance. C is an integer number; The projection plane indicator takes the following values: S is a real number; C = 1 for the XY plane; N is an integer number; C = 2 for the XZ plane; P, V, PS, VS are real arrays. C = 3 for the YZ plan
9、e. All parameters are input described in clause 4. parameters and their meaning is In t ,his notation, the P coordinate of a point corresponds the first axis and the V coordinate to the second axis. to 5.2 To retrieve a record from the file : GETLIN (IDENT, L, C, S, N, P, V, PS, VS) 4.3 Last data bl
10、ock The last data block which contains : in the file consists of one (1) record IDENT and C are input parameters; - END OF FILE; L, S, N, P, V, PS, VS are output parameters. file name: up to 24 characters; 6 Tolerances of projection representations - number of blocks in the file: (integer). The numb
11、er of segments in each projection general be different. of a line will in 5 Accessing the file at a logical level A line which does not lie in an orthogonal plane may be generated from two of its projections. The divergence between a line generated from a pair of its projections and the same line ge
12、nerated from another pair of its projections shall at any point be not greater than 1 mm. Access to the file at a logical level can be write/read procedures in 5.1 and 5.2. effected by the NOTE - The names of procedures are not standardized. Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
