understanding maps question

[I'm goin' down]

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]

Here is a discussion relating the relative depths for the colors

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

[tomoose]

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]

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]

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]

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

[I'm goin' down]

I did not understand Mannhausen's post. I am missing something basic I think.

[Nisgeis]

I did not understand Mannhausen's post. I am missing something basic I think.
If you want to plot a course due North, or a course of 000, then you'd drag your plot course line straight up, and therefore the plot line would run through the bottom of the bearing circle, so for you to plot 000, the bottom part must be 000.

Likewise, to plot a course East or 090, then you drag the line to the right and the line between the plot point and the submarine goes through the left of the bearing circle, so it should be labelled as 090 to correctly plot a course.

[Munchausen]

To illustrate:

Plotting your course ...
http://img.photobucket.com/albums/v97/pjcham/SH4/plotting_course.jpg
As in Nisgeis' example, you've set a course to the north using the navigator's compass. Since the course line only extends to the center of the compass rose, your true heading must be read along the back side.

Taking a target bearing ...
http://img.photobucket.com/albums/v97/pjcham/SH4/true_bearing.jpg
True bearing to the target is about 307 degrees ... again measured on the back side.

Measuring target heading ...
http://img.photobucket.com/albums/v97/pjcham/SH4/target_heading.jpg
This is the easiest method to plot your target's course ... anchor the line on your first fix, drag the compass over the target, then read the back side (in this case, about 089 degrees). If you like, you can also enter this target heading into the TDC by adjusting AOB.

[I'm goin' down]

I'm goin' down wants to introduce you to a couple of city gals and take you to dinner when your boats are in town (San Francisco), a great port town. Thanks. I could have never figured that one out!

[Munchausen]

I could have never figured that one out!

:hmm: I could never figure out San Francisco. Tried going to a dinner party in Twin Peaks once ... and ended up on Fisherman's Warf.

:o Too many one-way streets ... scary when you turn a corner and see three or four rows of headlights coming your way.