Sperry Marine Visionmaster FT ECDIS, User Manual

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Basic Operation of ECDIS ECDIS User Guide
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Scale Ratio
The scale ratio includes two selection modes: Automatic (AUTO) and
Manual.
The system defaults to AUTO scale selection on
first use. In Auto mode the scale ratio button on the
upper toolbar shows the letter
A after the scale.
Automatic Scale
In AUTO scale mode, the system periodically
checks the current scale of each display area for
ownship position against the compilation scale of
the largest chart. If the scales differ, the scale ratio
is automatically changed to the match the
complication scale of the chart.
To view or select the current compilation scale,
right click on the scale ratio button.
The drop down window shows the current scale
selection mode ticked.
1. For vector charts the manual scale ratios that
may be selected range from 1:500 to
1:20,000,000 and include a Compilation Scale,
which in AUTO scale will be ticked. For a
description of a chart's compilation scale, see
Chart Facility.
2. For raster charts a smaller
range of scale ratios are
available. The scales will be
dependent on the raster
chart currently selected, see
Using Raster Charts.
AUTO scale cannot be applied if True Motion limits
are off, for example in panning or zoom mode.