Presentation library
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- 10.3.3.7 No Symbol - Objects
- 10.3.3.8 Presentation of New Object NEWOBJ
- 10.3.4 Display Priority, Radar Priority, Display Category, Viewing group
10.3.3.6 Not set attributesThe symbology instruction may refer to attributes that are not listed in field 2, for example TX(OBJNAM). If these attributes are not set in the feature object, this particular command word shall be ignored and the rest of the symbology instruction shall be completed. 10.3.3.7 'No Symbol' - ObjectsIn some cases the "symbolization instruction"-fields in a look-up table line are empty. Such an explicitly "empty" instruction means that no actual presentation for the respective object is required by the presentation library. Such objects are not symbolized and they are not shown on the screen. For example, there is no symbolisation of a point BRIDGE feature The empty entry into the look-up table is simply for completeness. 10.3.3.8 Presentation of New Object NEWOBJThe ‘New Object’ feature class has been added to the S-57 Object Catalogue for detail on its use and encoding please see the S-57 Use of the Object Catalogue. NEWOBJ will cater for future requirements specified by the IMO that affect safety of navigation which cannot adequately be encoded by any existing S-57 object class. It will not be used unless approved by the Transfer Standard Maintenance and Application Development Working Group (TSMAD) and the Digital Imaging and Portrayal Working Group (DIPWG). For the presentation of objects of class NEWOBJ there are two defined presentations to be used depending on whether the SYMINS attribute is defined. To distinguish a new object symbol from the standard “Non ENC object” symbol (magenta question mark), an exclamation mark shaped in a magenta filled circle has been developed. The new symbol is named ‘NEWOBJ01’. If the SYMINS attribute is defined then it is used to symbolise the feature object using the CS(SYMINS01) conditional symbology procedure. IMPORTANT: Where the ECDIS fails to identify the symbol contained in the SYMINS attribute the SY(NEWOBJ01) shall be used as a default 10.3.4 Display Priority, Radar Priority, Display Category, Viewing group10.3.4.1 Display PriorityEach symbolization instruction except of text drawing from a look-up table line has a display priority given in field 4. Each symbolization instruction from a look-up table line has a display priority given in field 4. The display priority can be of a value between '0' and '9', where '9' identifies the highest priority. The display priority applies irrespective of whether an object is a point, line or area. If the display priority is equal among objects, line objects have to be drawn on top of area objects whereas point objects have to be drawn on top of both. If the display priority is still equal among objects of the same type of geometry (area, line or point) the given sequence in the data structure of the SENC, or some other neutral criterion, shall be used for an arbitrary decision as to which object is drawn on top. Text shall be drawn last (except for own ship etc.), in priority 8. The display priority shall be used to ensure that objects that overlap each other are drawn in the right sequence. Thus, an object with a higher priority shall be drawn after (on top of) an object with a lower display priority. However, if two line objects, or two area boundaries, or a line and an area boundary, are located at the same position and share the same extent (their coordinates are identical), then the line symbolization with the higher display priority shall suppress the line symbolization of the other object (line or area). Therefore only the line symbolization of the object (line or area) of the higher display priority is drawn. Where two objects share the same spatial edge and both have the same display priorities each line shall be symbolized.  
Fig 6. Symbolization of shared edges The coastline object is symbolized with a solid line while the anchorage area is bordered with a dashed line. Both objects share an edge that is part of the coastline. The symbolization of the coastline object suppresses the border of the anchorage area since the display priority of the coastline symbolization is higher. Note that priorities have to be evaluated again, if the presentation scale changes (see section 8.4). This suppression only applies to line objects and area boundaries. The rule for centred symbols, area patterns and point symbols is that all symbols shall be drawn with the highest priority object being drawn last independent of the geometric primitive (point, line or area). There is one exception to this rule for suppressing overlapping lines. The manual chart correction lines LC(CHCRIDnn) and LC(CHCRDELn) shall coexist with the underlying line. Both LC(CHCRIDnn) or LC(CHCRDELn) and the underlying line shall be drawn. Overdrawing may be essential, for example in the case of a buoy, and its name and light flare. These are given offsets in the symbol library to avoid the symbols being drawn over each other. The following table gives an indication of how priorities are allocated. Within each group priorities are adjusted to meet specific cases:
NOTE: To ensure seamless presentation of a single intended usage (navigational purpose) all objects of same display priority from all cells in same intended usage shall be draw together. Download 7.92 Mb. Share with your friends:
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