Navigators of /n/, how often do you refer to paper maps/charts?
Would you/your industry be totally screwed without GPS?
What is your primary backup if GPS fails?
As an aside, do trains carry maps? If they have to go though multiple switches who's in charge of keeping that straight?
I've been an infantryman in the Guard and have recently been flying as a civilian pilot, OP. I can tell you about military maps and aviation VFR sectionals, but not nautical charts
Both rely on a couple of common parts: You find a point with latitude and longitude, and the grid north is different from magnetic north, which your compass reads, requiring you to add or subtract the Grid-Magnetic, or GM, angle, before you go anywhere. They also mark key terrain, they have a massive legend to give you a reference of what's on the map and how to find the GM angle, and people generally overthink both
Other than that
Coordinates are given a prefix and broken up in even numbers, usually 6-8. The first four denote the grid square your point is in, read longitude-to latitude, right and then up. You then take the next 1-2 digits and use them to locate your point. So, if you're looking for point 12345678, you would find latitude line 12, then longitude line 56, and then use your protractor to go right until you found 1234, and up on that line until you found 5678. If you're trying to get from 12345678 to 13315669, you find those two points, draw a straight line between them, and use your protractor, oriented north, to find the grid direction. Then, you factor in your GM angle, get out your compass and point yourself in the appropriate direction and walk. There's also usually a very detailed depiction of the terrain and a lot of color-coding to help you understand what sort of vegetation you are going into. There's also Hidden Valley Ranch Salad Dressing, or the five major terrain features: Hill, Valley, Ridge, Saddle and Depression. Hill and valley are obvious, a ridge is a series of peaks, a saddle is the area between two high-points and a depression is an area of land lower than the surrounding terrain.
These use civilian latitude-longitude groupings, which are broken up into degrees, minutes and seconds. How you read them is based on what hemisphere you're in, but it's usually very apparent on the map how you find coordinates properly. If you're looking for 43 degrees, 50 minutes and 20 seconds North by 70 degrees, 53 minutes and 21 seconds West, you simply find the 43 N by 70 W grid square and work down from there, same as military navigation. Also similar is how you find your way between two points, simply draw a line between the two and take out your plotter to find the grid angle. There's a pinwheel on the top of your VFR plotter with a bunch of lines radiating out from the center with compass directions. You line them up on either a latitude or longitude line, depending on whether you're traveling north-south or east-west, and the number that it lines up with perfectly straight is your grid direction. Then, you simply factor in the GM angle and you have magnetic.
With aircraft there's the added complication of wind, which you use your E6-B and wind plotter to account for; you put the direction and speed on the wind plotter, spin the wheel to your magnetic course, put yourself at how fast you plan to fly and that will tell you what the wind will do to your speed and how hard it will throw you off course, giving you your Wind Correction Angle. Add that to your magnetic course, and that's the angle you set for your compass
The terrain is also less detailed on a VFR sectional, thanks to the area it covers; a military map will be about a 100 square mile area, whereas a sectional will cover an entire region. The major terrain features are still easy enough to pick out, but with a sectional you're going to need better dead reckoning skills than with a military map, dead reckoning being moving purely by azimuth
Lastly, this is a real down-and-dirty rundown of it, it's takes a few days to really get a handle of.
As for whether or not it's needed, yeah, it's needed for both, you're lost in the sauce without some sort of navigational acumen in both pursuits, and thankfully the two maps are read in an almost-identical fashion, just some different vocabulary.
I also find flying has a lot in common with mountaineering, but that's a different thread
OP here, I'm a mariner, and I'm somewhat familiar with military maps, from my time in JROTC.
It's interesting remembering back to what I was taught then, in high school, versus what I learned at my maritime college. The emphases are very different.
Aeronautical navigation is interesting to me because I haven't really had any exposure. Assuming you're actually en-route, do you basically just look at the ground to figure out where you are? Do you attempt to follow roads, or are you checking your assumed position against a series of landmarks?
Do small private planes typically have any electronic navigation systems besides GPS?
Sounds like a lot of math to figure out the course to steer (fly?), is this done religiously, or do people start flying and see how wind effects their progress? I assume with fuel and speed being much greater concerns, it's a much bigger deal than on ships.
Typically before you get aloft you mark out landmarks to navigate by if you're going VFR along your route. With IFR, you can't see any landmarks, so you're reliant on your GPS, and on ground-based navigational transponders like VORs that send out a signal for you to latch on to and guide yourself in towards the beacon with, letting you fly beacon to beacon without actually seeing the thing. Failing that, you better hope you're good at timing your route and your turns down and holding your azimuth
Also, I've always assumed maritime navigation had something similar, is that not the case? I'd assume you have to factor in sea currents, too, like you do with wind in an aircraft
VOR sounds neat, we've all but done away with radio-based navigation. D-GPS is king, and other than some really rusty Celestial Navigation, we're pretty much running blind (in open ocean).
This is a pretty typical Nautical Chart. Traditionally, you use this, plus a gyrocompass to triangulate your position relative to charted coastal features. You can also use radar range arcs to distinctive shoreline features to triangulate your position too.
We only really use magnetic compass as a backup.
In practice GPS trumps all, and you just use dividers and triangles to plot your latitude and longitude directly on the chart. Your route is plotted on the chart from pier to pier (pretty much), and each leg is labeled with the (true) course. Typically you attempt to steer the plotted course until you determine the set and drift, and adjust your course steered so that you "make good" the plotted course.
Those colored crisscrossing lines are obsolete holdovers from LORAN (a terrestrial radio-navigation system).
This ECDIS is what most ships use as their primary navigation system now. It just automatically plots you on a vectorized chart and gives you a bunch of useful extra real-time information.
The FAA determines when you use VRF vs IFR, right? And that's an extra rating on your license and for the aircraft as well?
I heard the FAA is very restrictive about the instruments that can be used in airplanes, is that true?
IFR is an additional rating on your license, and it's more the NOAA's Aviation Weather Center that tells you when you need to fly instruments.
GPS is what everyone primarily uses, but if you're going to get an IFR rate you need to have a working knowledge on how to use a VOR, though there is a push from the FAA to make everything GPS-based.
It's an idea that is catching some flak from aviators who don't really trust the technology as the sole source of navigational data, especially when you're cruising at anywhere from 100-250 knots and the margin for error is painfully small. Most GPS units are self-correcting, but it doesn't matter if the whole thing goes down. Hell, I had one go down just a week or so ago, thankfully I knew the area
I'd agree with keeping VOR. Any terrestrial system is going to be much more robust than GPS in the long run.
While we could technically still use Radio Direction Finding, nobody has the equipment, and from what I can tell, no effort has been made to modernize the system.
There's still tons of old nav beacons for aviation out there, too, like non-directional beacons, and most of them are still working. I think the NDBs are going the way of the Dodo, though, and they are rather superfluous