# Size and Orientation of a Vector-Symbol

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## 8.1 Size and Orientation of a Vector-Symbol

For each vector symbol the height and width are define in units of 0.01 mm.Symbols in the Presentation Library are already sized to give good readability and appropriate prominence. Only the ship symbol is allowed to be scaled to the actual dimension of the ship.

Every symbol has its own pivot point. The pivot point is the point around which the symbol is rotated. When a point symbol is placed on the display, the symbol's pivot point is positioned exactly on the object's position and all the instructions in the symbol’s definition are relative to that position. For further information about position of the pivot point and the symbol definitions, see section 11.6.

## 8.2 Description of Complex Line Style rendering.

A complex linestyle is formed from a repeating symbol. The symbol definition for a line style is very similar to the symbol definition for a point symbol and uses Cartesian coordinates as defined in the previous section. The linestyle symbol has its own pivot point around which it is rotated. The orientation is given by the direction between the two vertices of the segment of the line being drawn.

To symbolize some lines a composite type of complex linestyle is used, in which the unit is composed of a series of horizontal lines and symbols, strung together along the line object to form the linestyle unit
In order to draw a complex linestyle, first locate the start and end points along the edge to be symbolized. Then draw the complex linestyle along the edge between the start and end positions repeating as necessary. If a symbol needs to be embedded in the line, then the rotation angle relative to the line segment shall be determined. The diagram below shows how the composite symbol is created from the linestyle and its embedded symbols.

Fig 3. Complex Line Styles.

1. ## Sample Definition in Vector Format

 S-57 Feature Object S52 Symbol Vector Drawing Instruction (see 11.6.3) ECDIS Display Mooring/ Warping Facility MORFAC03 SYCL = 00747 SYRW = 00746 SYHL = 00253 SYVL = 00253 SBXC = 00603 SBXR = 00617 SCRF ALANDABCHBLK SVCT SPA;SW2;ST0; PU603,617;PM0;PD856,617; PD856,870;PD605,870;PD603,617;PM2;FP; SVCT SPB;SW2;PU603,617; PD856,617;PD856,870; PD605,870;PD603,617; SPA;SW2;ST0;PU603,617;PM0;PD856,617;PD856,870;PD605,870;PD603,617;PM2;FP;

8.3.2 Sample Symbol Library Format for Composite Complex Linestyle Symbols
The following sample Symbol Library sequence illustrates the step from the “Single Unit" type of complex linestyle to the "Composite" type. The complex linestyle achres51.lin LC(ACHRES51) has been modified as follows (refer to definitions of file formats):
Complex Linestyle achres51.lin:

LNST 10LS03354NIL

LIND 38ACHRES51001080081002729005030044600572

LXPO 64boundary of an area where anchoring is prohibited or restricted^_

LCRF 6ACHMGD

LVCT 29SPA;SW1;PU446,810;PD747,810;

LVCT 24PU595,810;SCVLINEMAG,2;

LVCT 25PU1208,810;SCNOANCHOR,2;

LVCT 31SPA;SW1;PU1655,810;PD1957,810;

LVCT 25PU1808,810;SCVLINEMAG,2;

LVCT 31SPA;SW1;PU2248,810;PD2552,810;

LVCT 25PU2404,810;SCVLINEMAG,2;

LVCT 31SPA;SW1;PU2874,810;PD3175,810;

LVCT 25PU3024,810;SCVLINEMAG,2;

NOTE: The VLINEMAG and NOANCHOR symbols will be embedded in the linestyle at the position given by the last position of the pen before the inclusion the embedded symbol. The only vectors in this linestyle are the four horizontal dashes that are to be drawn.
Symbol noanchor.sym:

SYMB 7SY00000

SYMD 39NOANCHORV012070084800431005030098700572

SXPO 36Anchor symbol with a line through it

SCRF 6ACHMGD

SVCT 32SPA;SW1;PU1208,572;PD1208,1074;

SVCT 31SPA;SW1;PU1052,721;PD1356,721;

SVCT 55SPA;SW1;PU1005,971;PD1111,1075;PD1309,1075;PD1407,974;

SVCT 31SPA;SW1;PU1418,640;PD987,1071;
Symbol vlinemag.sym:

SYMB 7SY00000

SYMD 39VLINEMAGV005950081000010000100059500810

SXPO 28Vertical Chart-Magenta Line

SCRF 6ACHMGD

SVCT 29SPA;SW1;PU595,810;PD595,970;

## 8.3.3 Sample Implementation of the Composite Complex Linestyle Symbols

The following is a simplified example for determining rotation of the symbol that is part of the complex linestyle. This example uses the ACHRES51 complex linestyle described in the documentation.

Each symbolization instruction will be drawn in sequence. The diagrams are as follows:
STEP 1: Draw the first straight line segment along the edge of the object.
LVCT 28SPA;SW1;PU446,810;PD747,810;

The edge to be symbolized.

Direction of the line.

STEP 2: Draw the first LINEMAG symbol at position 595, 810.

LVCT 23PU595,810;SCVLINEMAG,2;

STEP 3: Draw the first NOANCHORsymbol at position 1208, 810.

LVCT 24PU1208,810;SCNOANCHOR,2;

Determine the angle of the slope of the line at the position 1208, 810.
if x1 = 5 and y1 = 10

x2 = 10 and y2 = 5

The angle of the slope of the tangent is 135 degrees. Remember that 0 degrees is in the direction of the y-axis.
Subtract 90 degrees to determine the rotation of the symbol.
135 - 90 = 45 degrees.

Direction of the line.

STEP 4: Repeat with the other straight line segments and the VLINEMAG symbols.
LVCT 30SPA;SW1;PU1655,810;PD1957,810;

LVCT 24PU1808,810;SCVLINEMAG,2;

LVCT 30SPA;SW1;PU2248,810;PD2552,810;

LVCT 24PU2404,810;SCVLINEMAG,2;

LVCT 30SPA;SW1;PU2874,810;PD3175,810;

LVCT 24PU3024,810;SCVLINEMAG,2;

The resulting line is ...

Direction of the line.