How to Find Latitude and Longitude on a Nautical Chart

Any GPS receiver will obtain Latitude and Longitude along your sailing routes at any moment. But as a skipper, have you plotted this info on to a nautical chart to verify your placement? Raise your sailing navigation abilities to the up coming stage with this essential sailing ability!

Navigating with Latitude

Cartographers create a grid-like world wide web on your navigation chart. Latitude strains run in a horizontal direction. Longitude traces run in a vertical route. Envision the earth, balanced on her axis with no a tilt. Wrap a “belt” all around the earth, divide it in two and you have the equator–birthplace of Latitude. Label the equator degrees.

Latitude lines parallel the equator to the north or to the south. To plot Latitude to find out exactly where you are, you evaluate how lots of levels you are north or south of the equator. Latitude reaches a highest of 90 degrees at the two north and south poles. Generally label Latitude N, if north of the equator, or S, if south of the equator.

In chart navigation, use the scales on the proper or remaining facet to come across your Latitude. These scales are damaged down into degrees, minutes and tenths of a minute, or levels minutes and seconds. One particular diploma of Latitude equals sixty minutes just one minute of Latitude equals sixty seconds. This is a simple way to don’t forget this:

1 diploma = 60 minutes.
1 moment = 60 seconds.

Navigating with Longitude

Return to your imaginary globe. To evaluate Longitude, you yet again divide the earth in half, but this time lengthwise. Find Greenwich, England on your globe. Attract a line about the earth that intersects Greenwich and both north and south poles. Cartographers call this the Greenwich, or primary meridian–the birthplace of Longitude. Label the Greenwich meridian levels.

Longitude traces parallel the vertical Greenwich meridian to the east or to the west. To discover longitude, you evaluate how lots of degrees you are east or west of the Greenwich meridian. Longitude reaches a greatest of 180 levels on the other facet of the earth, at the Intercontinental dateline. You must label Longitude E, if east of Greenwich, or W, if west of Greenwich.

Use possibly the major or base of the chart to evaluate Longitude. Like Latitude, Longitude is damaged down into levels, minutes and tenths of minutes or levels, minutes and seconds.

How to Convert Increments of Minutes

All nautical charts demonstrate minutes damaged down into increments so that you can plot parts of a moment. For instance, if your gps position demonstrates 23-13N 82-16W, there are no increments to stress about. But, if your gps place displays Latitude 23-13.278N Longitude 82-16.786W, you have increments of minutes. In advance of you plot your posture, round off increments to the closest tenth of a moment. Round off like this: Latitude 23-13.3N Longitude 82-16.8W.

Search at the Latitude scales (ideal or still left aspect) and Longitude scales (prime or base) on your chart. Are minutes broken down into tenths or into seconds?

Some charts show levels, minutes, and tenths of a moment. The minutes will be broken down into 10 tiny segments. Each compact section equals one-tenth of a minute. Other charts clearly show levels, minutes, and seconds of a minute. If your chart reveals degrees, minutes, and seconds, you will have to have to multiply the “tenths” of a moment by 6. Comply with this example:

GPS reading through (with minutes rounded as explained earlier): Latitude 23-13.3N Longitude 82-16.8W.
Multiply the increment of Latitude minutes like this.3 X 6 = 18 seconds.
Multiply the increment of Longitude minutes like this.8 X 6 = 48 seconds.
Plot: Latitude 23 degrees, 13 minutes, 18 seconds Longitude 82 levels, 16 minutes, 48 seconds.

How to Plot Latitude and Longitude

Use a pair of dividers to plot your posture by Lat and Extended onto the chart. Read the degrees and minutes from your GPS. Discover the closest degrees and total minute of latitude on your GPS.

For case in point, for Latitude 23-13.3N, you would appear for 23 levels, 13 minutes on the suitable or left facet scales on your navigation chart. Thrust one particular position of your dividers into the 13 minutes. Open up the other leg 3 compact segments (3 tenths), over the 13 minute mark. If your chart displays seconds as a substitute of tenths, open up up the other leg of your dividers 18 seconds (.3 X 6) above the 13 moment mark. Put a pencil mark where by the dividers contact the actual Latitude.

Future, plot your Longitude. Use the identical specific technique to plot your Longitude. Make confident to use the leading or bottom chart scales to plot your Longitude. When you have discovered your Longitude, put a pencil mark the place the dividers contact the correct Longitude.

Locate Your Exact Situation

Align your parallel regulations or any other straight edge so that the major prolonged edge touches the Latitude pencil mark. Make the parallel rules or straight edge perpendicular so that when you draw in the Latitude line, it will be parallel to all other latitude traces. Attract a light pencil line across the body of the chart to a area shut to the place you marked the prime or base Longitude scale.

Repeat this exact system to align and attract in your Longitude line. Where by the Longitude pencil line intersects the latitude pencil line displays your exact posture. You really should now have a cross. Spot a dot exactly where the two strains cross. Circle the dot. Erase the mild strains drawn from the edges of the chart to thoroughly clean up the chart and keep your plot neat.

Use these straightforward techniques to find Latitude and Longitude on your nautical chart speedy. With these sailing techniques, you will be well on your way to develop into a assured sailing skipper-everywhere you decide on to go sailing!