understanding maps question

I'm goin' down · 10-31-08, 03:34 AM

How to you read a nautical map? are there any posts that discuss it. I looked and could not find a basic one. I do not understand what the term minutes mean in longitute and latitude describptions. Also, what about may coloring, such as white or shaded areas in the ocean?

SteamWake · 10-31-08, 09:32 AM

Here is a discussion relating the relative depths for the colors

http://www.subsim.com/radioroom/showthread.php?t=108983

tomoose · 10-31-08, 12:53 PM

I'm a landlubber, used to contour maps with grids but the principle is the same with nautical maps. Hopefully I don't screw this up.

i.e. 65° 32' 15" = 65 degrees 30 minutes 15 seconds.
If you look on your chart you'll see the grid lines clearly marked with similar numbers(without seconds as the map is not that accurate), the lines themselves being actual degrees and the second number the minutes, each grid being divided into 60 minutes (they are not marked you'll have to guesstimate). The number on the horizontal lines is latitude (Lat) and the Equator is basically your zero line, latitude lines always being parallel to the Equator, the number on the vertical is longitude (Long, aka a meridian line), the zero mark being Greenwich, UK (Prime Meridian).

When finding a lat and long on a chart, it's basically "up/down the stairs and out the door"; up/down(depending on which side of the equator you're starting from) the horizontal (lat) lines (like a stair) and find the first number then left or right (depending on which side of the Prime Meridian) towards the vertical lines indicating the longitude (long) number.

Lat and Long are further clarified with regard to which direction by using North, South, East and West with the numbers.
e.g. Sydney, Austrailia is 33° 52' S and 151° 13' E
Obviously Sydney is South of the Equator and East of the Prime Meridian. Although I don't think the charts in the game use the letters.

Hope this helps.

breadcatcher101 · 10-31-08, 03:04 PM

One thing on my map I don't understand is the 360 degree compass. Seems to be backward, 90 degrees is where 270 should be, zero is where 180 should be. Is this right? I have stock game, 1.4.

Munchausen · 11-01-08, 06:37 PM

Quote:

Originally Posted by breadcatcher101

One thing on my map I don't understand is the 360 degree compass. Seems to be backward, 90 degrees is where 270 should be, zero is where 180 should be.

The compass is for plotting your course and/or taking a bearing. It's anchored at your submarine ... so, when you drag it out to where you want to go (or where your target is positioned), the true heading/bearing can be read along the plotted line.

That happens because the compass rose is backward. Else, you'd need to first draw the line and then, afterward, use the compass to measure the line. That would work okay for bearings but would make it difficult to plot a specific course.

breadcatcher101 · 11-01-08, 07:19 PM

Thanks for explaining that for me. Always wondered about that one.

10-31-08, 03:34 AM	#1
I'm goin' down Ocean Warrior Join Date: Sep 2008 Location: Notify command we have entered the Grass Sea Posts: 2,822 Downloads: 813 Uploads: 0	understanding maps question How to you read a nautical map? are there any posts that discuss it. I looked and could not find a basic one. I do not understand what the term minutes mean in longitute and latitude describptions. Also, what about may coloring, such as white or shaded areas in the ocean?

10-31-08, 12:53 PM	#3
tomoose Grey Wolf Join Date: Aug 2005 Posts: 930 Downloads: 23 Uploads: 0	Minutes and degrees I'm a landlubber, used to contour maps with grids but the principle is the same with nautical maps. Hopefully I don't screw this up. i.e. 65° 32' 15" = 65 degrees 30 minutes 15 seconds. If you look on your chart you'll see the grid lines clearly marked with similar numbers(without seconds as the map is not that accurate), the lines themselves being actual degrees and the second number the minutes, each grid being divided into 60 minutes (they are not marked you'll have to guesstimate). The number on the horizontal lines is latitude (Lat) and the Equator is basically your zero line, latitude lines always being parallel to the Equator, the number on the vertical is longitude (Long, aka a meridian line), the zero mark being Greenwich, UK (Prime Meridian). When finding a lat and long on a chart, it's basically "up/down the stairs and out the door"; up/down(depending on which side of the equator you're starting from) the horizontal (lat) lines (like a stair) and find the first number then left or right (depending on which side of the Prime Meridian) towards the vertical lines indicating the longitude (long) number. Lat and Long are further clarified with regard to which direction by using North, South, East and West with the numbers. e.g. Sydney, Austrailia is 33° 52' S and 151° 13' E Obviously Sydney is South of the Equator and East of the Prime Meridian. Although I don't think the charts in the game use the letters. Hope this helps.

10-31-08, 09:32 AM	#2
SteamWake Rear Admiral Join Date: Mar 2005 Posts: 13,224 Downloads: 5 Uploads: 0	Here is a discussion relating the relative depths for the colors http://www.subsim.com/radioroom/showthread.php?t=108983

10-31-08, 03:04 PM	#4
breadcatcher101 Captain Join Date: Sep 2008 Location: Southeastern USA Posts: 546 Downloads: 1 Uploads: 0	One thing on my map I don't understand is the 360 degree compass. Seems to be backward, 90 degrees is where 270 should be, zero is where 180 should be. Is this right? I have stock game, 1.4.

11-01-08, 07:19 PM	#6
breadcatcher101 Captain Join Date: Sep 2008 Location: Southeastern USA Posts: 546 Downloads: 1 Uploads: 0	Thanks for explaining that for me. Always wondered about that one.