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Step 1: the shooting..
Place the chart on the floor in a well lit room.
Hold the camera straight and vertical to the
center at a height to fit the useful part of the
map. Sometimes it is better to remove a little
camera and zoom as a wide angle lens may provide
more distortion.
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Step 2: load the chart into StarNavPilot.
Load the picture into your computer and open it
with the command 'Load a scan or a raster chart'.
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Step 3: Fix a possible inclination of the
shooting.
Despite all the attention that you could bring to
the shooting, it is likely that the chart looks a
little. The first thing to do is to correct the
tilt which takes 2 clicks on a horizontal line
with the corresponding function of StarNavPilot.
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Step 4: The georeferencing.
Georeferencing is to provide the coordinates of
at least 2 points on the chart and as far as
possible vertically and horizontally. You will
then choose a point in the upper left corner of
the chart (NO) and a point in the bottom right
corner (SE) of the chart. On a nautical chart the
simplest way is to use the crossing of parallels
and meridians, but you can also choose points on
the graduated edges of the chart.
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Verification of the chart:
At this stage the chart is georeferenced and if
the shooting was done with a good camera, it can
be used as this. Check by moving the cursor on the
surface of the charts if the positions of
parallels and meridians are accurate over the
entire surface of the chart. If you notice any
discrepancies you have to apply some corrections
to this charts. This is usually the case because
of the optical defects of common lens or a slight
tilt at the shooting.
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Step 5: Apply corrections georeferencing.
On a nautical chart it is very easy to apply a
correction grid. Just create a correction point at
each intersection of parallels and meridians.
These corrections are very easy to enter because
it needs simply to round the coordinates of the
points. For example, if you read W004 ° 10'06"and
N47 ° 19'48" at the intersection of meridian 4 °
10 'and paralell 47 ° 20 you just need to round
the coordinates of this point to W004 ° 10' and
N47 ° 20 '.
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The chart is ready:
This chart is now operational. After further
check by moving the cursor on the surface of the
chart that the positions of parallels and
meridians are accurate over the entire surface of
the chart, lock the georeferencing of the chart to
prevent accidental changes. You can say that you
scanned your chart and that it has become an ENC
(Electronic Nautical Chart).
IMPORTANT: Back up your digital charts.
StarNavPilot has an export charts function. You
can export all or parts of your charts to mobile
supports or even CD ROMs or DVD. A StarNavPilot
charts CDRom or DVD has at its root an autonomous
installation utility allowing to select the charts
to reinstall. In case of problem, you can then
reinstall your charts on your computer or even on
another computer if you use multiple computers on
your boat or if you have created your CDrom or DVD
with another computer than the one of your boat.
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