The main advantage of vector data format is the accuracy in representing point features, limitations and straight lines.<\/span> This is very useful for analysis that requires precision positioning, for example on the boundaries of the cadastral database.<\/span> Examples of other use is to define the spatial relationship of some features.<\/span> Vector data is relatively more economical in terms of file size and precision in the location, but it is very difficult to use in computational mathematics.<\/span><\/p>\n Vector data is the shape of the earth are represented in points, lines, and areas.<\/span> Line is a collection of several points, while the area is the area bounded by a line which starts and ends at the same point.<\/span> While the raster data typically requires storage space larger files and lower precision location, but easier to use mathematically.<\/span> The main weakness of vector data is its inability to accommodate gradual change.<\/span><\/p>\n a) Entities (geometries) Point<\/strong><\/span> This data can include information such as the display size and orientation of the symbol.<\/span> If the ‘point’ is an entity of text, then other data associated with this entity will contain information characters to be displayed, the font (style) is used, the text alignment (right, center, left), scale, and orientation.<\/span> b) Entities (geometries) Line<\/strong><\/span> In relation to the vector data model entities geometries on the line, often used terms such as ‘arc’, ‘chain’, and ‘string’;<\/span> which is a set of pairs of coordinates (x, y) which describes a continuous line which is complex.<\/span> Shorter segments constituent lines, the more number of pairs of coordinates (x, y) is involved in it, and the more subtle form of curves (complex) which can represent.<\/span><\/p>\n
\n Entities point covers all the graphics objects associated with or geographical coordinate pair (x, y).<\/span> In addition to the coordinates (x, y), associated with the geometry ‘point’, the data must also be stored in a manner to indicate the type of ‘titik’ her.<\/span> For example, the ‘point’ can be a symbol that is not associated with any other information.<\/span> Or, ‘point’ is a symbol that has ties to other data.<\/span><\/p>\n
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\n Figure 3. Entity Point<\/span><\/p>\n
\n<\/strong> Entities line can be defined as all elements are built using the linear line segments formed by two coordinate points or more.<\/span> The simplest line entities will require space to store the starting point and end point (two couples coordinate [x, y]) along with other information about the symbols that will be used to present it.<\/span> For example, the parameters can be called to display the symbol of lines discontinuous (dashed) or not (solid) on the monitor display device.<\/span>
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\n Figure 4. Entities line<\/span><\/p>\n