Sperry Marine VISIONMASTER FT ECDIS-E, Руководство пользователя

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ECDIS-E User Guide Charts
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About Charts
Chart Types
The VisionMaster ECDIS has the capability of displaying charts in a
number of formats on all presentation windows.
Chart types are divided into two basic categories:

Vector charts: vector chart data is stored in a chart database. The
chart is drawn on screen based on processing of the various stored
data elements within the database. Vector chart databases include
SevenCs S57 (ENC) NAVTOR ENC and C-MAP charts.

Raster charts: the chart shows a scanned version of a traditional
paper chart, with the chart images stored as graphic files. Raster
chart types include ARCS charts, which are supported by the
SevenCs chart engine.
Safety checking does not occur when using raster charts, see
Using Raster Charts .
For a detailed description of the chart databases available from the
SevenCs and C-MAP chart engines refer to `Chart Databases’.
When S57 charts are installed, the ENC data undergoes a conversion
process. The result of this conversion is the creation of the SENC
database. It is this database that is accessed and displayed by ECDIS.
For information on installing all chart types, refer to Appendix A `Chart
Installation’
Factors affecting Chart Accuracy
A position plotted on a navigational chart is only as good as the accuracy of
the chart. Therefore it is important to understand the factors which may limit
the accuracy of both raster and vector charts. These factors are detailed
below.
Survey Data
Vector charts are generally based on recent hydrographic survey data.
However, the level of detail provided by different types of chart data may
vary greatly depending upon the geographic location, these charts may
sometimes use old survey data where more recent surveys do not exist.