Lesson 1 - Position
Here’s how it works:
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Degrees ° These are the main units of latitude and longitude.
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Minutes ' Each degree is split into 60 equal parts.
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Seconds " Each minute is divided into 60 smaller parts.
For example:
A latitude of 45° 30' 15" N means:
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45 degrees north,
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30 minutes,
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15 seconds north of the Equator.
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A longitude of 60° 15' 45" W means:
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60 degrees,
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15 minutes,
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And 45 seconds west of the Prime Meridian.
Horizontal datums
These define the exact position of features like lighthouses or reefs on the Earth’s surface using latitude and longitude.
Most marine charts rely on WGS84 a global standard that ensures consistency, especially with GPS systems.
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Horizontal datums
These define the exact position of features like lighthouses or reefs on the Earth’s surface using latitude and longitude.
Most marine charts rely on WGS84 a global standard that ensures consistency, especially with GPS systems.
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Dealing with Datum’s
If you're using electronic navigation, ensuring your GPS matches the datum of your chart is critical. Many devices allow automatic or manual conversions.
For example, a waypoint plotted on WGS 84 might need adjustments to align with charts based on older datums.
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