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| BlueChart®
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| Using BlueChart
Cartridges |
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BlueChart cartography is "object oriented",
meaning that each feature displayed can be associated with
additional
information. For example, when placing the chartplotter’s
cursor on a navigational aid, a window can be displayed with
additional information for the selected navigational aid. |
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BlueChart cartography also provides paper chart-specific
information such as chart publisher, print date, edition date,
NTM (Notice to Mariner), correction date, and scale. Additional
notes are available for paper charts, including details on
caution or warning areas, pollution areas, and what unit of
measurement was used in capturing the soundings, depths, bridge
clearances, etc. To display paper chart-specific information,
place the chartplotter’s cursor on an open area of the
chart (absent of any chart features) and press ENTER. A window
will appear showing the chart information and allowing you
to view any additional notes about the chart area. |
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BlueChart data is not seamless. Just like the
paper charts from which the data is derived, you may observe
some discontinuity along chart borders. For example, if a contour
is present on one chart, and not on the adjacent chart, the
BlueChart data will be represented on your chart-plotter in
the same manner. Likewise, if adjacent paper charts used to
generate BlueChart data are of different scales, you may encounter
shaded areas on the chartplotter’s map screen. This can
occur at any zoom level and can be easily remedied by zooming
out one or two scale levels. |
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A feature of presenting data in a chart-by-chart
manner is selecting only those paper charts that you have on
hand or that you want displayed on the chart-plotter. By default,
all available charts will be displayed. See your chartplotter’s
owners manual for specific steps, but the screen will generally
appear as shown at left. From this screen, use the chartplotter’s
on-screen cursor and ENTER key to deselect (remove the check
mark from the box) the individual paper charts you do not wish
to display. |
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Garmin now offers an additional type of BlueChart
cartography that is designed for fisherman. We refer to this
as Bathymetric. The detail in our bathymetric charts includes
many depth contours, names of local canyons, wrecks and obstructions,
etc. These types of charts are designed to be used in conjunction
with our traditional BlueChart data, as bathymetric type charts
do not contain all the necessary navigational information.
Bathymetric data is intended to be used as a fishing chart
and should be used as a supplement to detailed BlueChart cartography. |
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| Symbols
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BlueChart electronic charts make extensive use of graphic
symbols to denote map features.
Some common symbols you will see
on the map display include (but are not limited to):
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Anchorage berth |
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Fishing harbor |
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Airport/seaplane base |
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Information |
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Fishing prohibited |
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Yacht harbor |
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Beacon |
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Exposed wreck |
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Isolated danger |
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Wreck |
Other features common to most BlueChart data are:
- Depth contour lines (with deep water represented in white)
- Inter-tidal zones (displayed in green on color chartplotters)
- Spot soundings as depicted on the original paper chart
- Navigation aids and symbols
- Obstructions and cable areas
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| The Difference
Between Pixels and Paper |
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Occasionally, boaters notice that their electronic
chart doesn't duplicate a particular feature shown on the paper
chart they are using. The reason is this: Garmin® uses all
of the best charts available and carefully turns the paper charts
into
a digital format for display on electronic chartplotters. If
there are errors, omissions, or discrepancies on paper, they
may occur
electronically too.
On paper charts, sometimes even large features
like a breakwater may not be shown clearly or at all. Large breakwaters
are sometimes
not shown on the harbor charts, but are shown on coastal charts—or
vice versa. These decisions are made by the chart maker, such
as NOAA/NOS.
In some cases, bridges or other features washed away
in storms decades ago are still shown on the paper charts. Recent
changes
in coastlines are often not reflected on paper charts for years.
The same is true for new marinas and ports. Sometimes, well-known
local landmarks may be shown so small on the paper chart that
they are indistinguishable from surrounding features to someone
not familiar with the area. In these cases, a feature may not
be accurately depicted on the electronic chart.
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| What Should
I Do if I Notice a Chart Error? |
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Even when a feature is shown on the paper chart,
it can be overlooked or misspelled during the data entry process.
These are small problems that can be easily corrected and do not
affect the quality of the overall electronic chart. If you notice
something missing or incorrect on your electronic chart, fi rst
check the best available scale paper charts of the area to see how
the feature is represented on the paper chart. If we have not represented
it accurately, or you know additional information about the feature,
please visit our website and fi ll out the on-line
error report form.
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