Cardinal directions?

[Osmeen]

what exactly is the logic in having the GPS coordinates operate in this way?

[Blu3wolf]

What exactly is the logic in having the airspeed tape on the left hand side?

[Leech]

@Osmeen:

what exactly is the logic in having the GPS coordinates operate in this way?

You mean why the need to prefix coordinates with N S E W?
If yes, think about this

37° 59’ 2.1012’’ latitude
23° 43’ 45.6960 Longitude
Sweet.
But where is that? is the latitude in the North hemisphere or South ?
Is the longitude east or west?
Now try this

N 37° 59’ 2.1012’’ latitude
E 23° 43’ 45.6960 Longitude

Now that looks much more helpful doesn’t it.

[Osmeen]

so you determine where is north and the geographic (or magnetic) north is not necessarily the north defined by GPS coordinates?

[Blu3wolf]

No and no respectively.

[sthalik]

Standard basis and signs of thereof are arbitrary in any case.

[Osmeen]

well then how would you know yourself which letter to choose from the NSEW to punch in a new GPS coordinate for a chosen waypoint?
say, for example, I chose waypoint 15, now should I click N or S or E or W to punch in, say, the GPS coord. of Kadena

[Blu3wolf]

Kadena is N and E. If its North of the equator, use N. If its East of the prime meridian, use E.

Given that that applies to all of KTOs terrain, I think you can afford to just use N and E all the time in that theater.

[Osmeen]

so you have to know the approximate compass location of the destination. If I punch S for Kadena that should be an error, I will check that tonight.

[Blu3wolf]

Errr… if you are setting the exact coordinates of a steer point, you need to know the exact coordinates. If you only know the approximate location relative to the surface of the earth, what do you need to modify steerpoint locations for?

[Osmeen]

what I meant is if I punch in S and E for Kadena, then what would I get? so I know exactly the coord. of Kadena but I decided that it S and E not N and E

[Blu3wolf]

Well, in BMS I dont think it will let you put in anything other than a N and E. If you can, the way it works in the real jet would direct you along the GCSC towards the point S and E. Presumably somewhere in South Australia I would imagine. Definitely out of your range at least anyway.

[Frederf]

Coordinate input is non-responsive if you select S or W in Korea in BMS (like you hit no key).

Logic is “because the F-16 does it.” It doesn’t have to make sense it just has to mimic. It’s a simulator.

[Osmeen]

by logic I meant navigational logic, so I guess I was asking why would the F-16 do it this way. Obviously we have to know if our target point is toward N or S or E or W in addition to the knowledge of the exact GPS coordinates.

[Blu3wolf]

Er… the exact GPS coordinates include the cardinal direction, you realise? Its not saying you need to travel E or N to get there - its saying the point is so many degrees from the equator (degrees latitude) and so many degrees from the prime meridian (degrees longitude).

[Osmeen]

I see, and it is because we are in the Korean region that all GPS coord. are either N or E?

[Osmeen]

@Leech:

You mean why the need to prefix coordinates with N S E W?
If yes, think about this

37° 59’ 2.1012’’ latitude
23° 43’ 45.6960 Longitude
Sweet.
But where is that? is the latitude in the North hemisphere or South ?
Is the longitude east or west?
Now try this

N 37° 59’ 2.1012’’ latitude
S 23° 43’ 45.6960 Longitude

Now that looks much more helpful doesn’t it.

I think you meant:
N/S 37° 59’ 2.1012’’ latitude
E/W 23° 43’ 45.6960 Longitude

[Blu3wolf]

@Osmeen:

I see, and it is because we are in the Korean region that all GPS coord. are either N or E?

Yes. All of Korea is to the North of the Equator, and to the East of the prime meridian.

@Osmeen:

I think you meant:
N/S 37° 59’ 2.1012’’ latitude
E/W 23° 43’ 45.6960 Longitude

There is no such thing as N/S 37° 59’ 2.1012" and E/W 23° 43’ 45.6960".

A WGS84 coordinate consists of a direction from a reference arc, and an angle from that reference arc along the direction given.

For instance, N 37° 59’ 2.1012" describes a specific line of latitude - a plane parallel to the plane of the equator. S 37° 59’ 2.1012" describes another specific line of latitude, but on the opposite side of the equator. One of these planes is nearly 38° North of the Equator, and the other is nearly 38° South of the Equator.

Similarly, E 23° 43’ 45.6960 Longitude is an arc along a great circle which at the equator is found roughly 23° from the Prime Meridian, heading East. W 23° 43’ 45.6960 Longitude is a corresponding arc along a great circle found about 23° from the Prime Meridian, heading West.

Saying E/W 23° 43’ 45.6960 Longitude is saying two different arcs. Saying N/S 37° 59’ 2.1012’’ latitude, E/W 23° 43’ 45.6960" Longitude is saying 4 different locations on the earth’s surface (one at each intersection of the 4 lines described).

EDIT: and yes, Leech typoed, he meant East longitude rather than South longitude (the latter not existing).

[thunder]

It’s really not that hard:

• take a globe and point your finger at Korea
• imagine the earth is divided in two halves, horizontally; the line that divides the earth horizontally is called “Equator”
• Is your finger in the top half? I suppose it is, so that means it’s North of the Equator.
• Now go find London, UK; There’s a place called Greenwich that you might have heard of, it’s really close to London anyway. Imagine a line running from the North Pole to the South Pole, that cuts right through Greenwich: this is the “Prime meridian”.
• Is your finger to the right of Greenwich or to the left? I suppose it’s to the right, since Korea is East of the UK and east of the Prime Meridian.

Therefore as you can see, any place in Korea is both North of the Equator and East of Greenwich, that’s why you have N and E before the numbers.

[Dee-Jay]

@Osmeen:

so you have to know the approximate compass location of the destination. If I punch S for Kadena that should be an error, I will check that tonight.

Geographic coordinate system
[

](https://en.wikipedia.org/wiki/Geographic_coordinate_system)