posted
There is no Trekkified answer to this that I know of, but consider this:
My masters degree is in Geographical Information Systems (GIS), or the utilization of computer technologies in generalized map making, satellite photo analysis, and working with dynamic geographical features with hi-tech stuff. My line of work involves a lot of knowing where certain things are, and how a computer will be able to know that and analyze stuff therefrom.
While we talk a lot of where stuff is in the galaxy (a sub-field of GIS which is not heavily utilized, surprisingly), we don't often talk about stuff the planets in Trek. This is generally due to the fact that these planets are not described or seriously mapped during the course of the show. However, there are many things in Trek for which GIS technologies can be extremely useful; making planetary maps, analysing orbital sensor readings, determining transportation coordinates, etc.
It's this last one I was wondering about in the lab today. As we know, rocky planets are not spheroid as much as they are slightly squashed on the pole side, making the circumference of the equator larger than the circumference of any polar loop. Now, current-day geography accounts for this with computational technology, assigning spheroidal coordiates on a non-spheroid planet. We do this by starting with a DATUM, or an arbitrary point on the spheroid which serves as a zero point from which to measure stuff. For example, most North American GIS people use a datum called NAD83, which is centered somewhere in Africa I think (being the intersection of the equator and the GMT longitude).
But let's say a starship comes across a planet - how do you decide where to begin? You *need* a datum to be able to tell the away team where they are, and where to go from there. Whenever someone looks at a tricoder and says that something is in some direction and some distance, it must be not only in reference to where they are, but to some zero-point on the planet for reference. One wonders how this place is chosen? Logically it could be the place where the away team or whatever beams down, or more appropriately on the planet's equator at some arbitratry point. Whenever a starship pulls into orbit on any Trek show, there should be some nobody in the bowels of the ship analyzing sensor telemetry, making the first maps of the planet, deciding on this datum and other key geographical needs for the prelimiary exploration of the planet.
I guess I'm really just saying that in the Trek universe, *I* would be that nobody. Make me fell all warm and fuzzy inside, I tells ya.
posted
That's an interesting concern... now that I think about it, I can't recall a single time that they gave anything more specific then "Sir, we have the beam-down coordinates," and other lines to that same effect.
The equator is an easy point to start at, but as you've pointed out, it'd be difficult to draw latitude lines because you'd have to pick some sort of arbitrary location to start from. At first, I played around with the idea of a starship merely creating coordinates based on relative position in the same manner as starship navigation, but quickly realized that wouldn't do for obvious reasons.
The only worth-while idea that I can come forth with on the issue is that Star Trek might use some sort of three-dimensional coordinate system for planets that differs from our longitude/latitude one, since often they end up beaming into underground locations. On top of that, terraforming activities often require the use of phaser drills or stations that do things quite far below the surface. Then again, you can just plot the point and then give the location as being whatever meters below the surface.
Oh well, we still have a few hundred years to come up with something. Anybody have information on how other planets, such as Mars and others in our solar system, are plotted today?
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posted
Well... maybe they do something like arbitrarily assign a new planet's "International Date Line" as the morning terminator line when a Federation starship assumes standard orbit. Given that if it's an unexplored planet, then the explorers are going in completely without references, and so basically would have to choose a point randomly. Or almost randomly.
-------------------- “Those people who think they know everything are a great annoyance to those of us who do.” — Isaac Asimov Star Trek Minutiae | Memory Alpha
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posted
"The Mark of Gideon" featured transporter coordinates that consisted of three numbers. Presumably, these were intended to be x, y, and z coordinates, but it was never explicitly said in the episode. Just the numbers were given.
Registered: Mar 1999
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posted
Hmm, why not just a 3-dimensional coordinate system either based at the center of the planet? Then you wouldn't need to decide on some arbitrary date line, or compensate for the curvature...
Registered: Mar 1999
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posted
Sure you would. Assuming you're running three axes intersecting in the centre of the planet, which way they're rotated is still relevant. Basically, it's impossible to lock down any location without a frame of reference like a Prime Meridian.
How was Mars' Prime Meridian set, out of curiosity?
-------------------- "I was surprised by the matter-of-factness of Kafka's narration, and the subtle humor present as a result." (Sizer 2005)
Registered: Mar 1999
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posted
Another possibility would be to have some rules for establishing the "Greenwich Mean 0 Coordinate". Fer-instance, on planet like Earth that has a magnetic pole, you could set up the 0 coordinate of a longitudinal line that would go from the true poles through the magnetic poles. Course, then you'd have to decide which hemisphere is "north". Yes, I know not all planets would have magnetic fields, but it was an example.
There could be other rules, perhaps just as arbitrary, but based on specific criteria so that the next ship that came along could figure out just where those transporter coodinates to the Sorority Girls of Planet Playtex� pointed.
-------------------- "Well, I mean, it's generally understood that, of all of the people in the world, Mike Nelson is the best." -- ULTRA MAGNUS, steadfast in curmudgeon
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Venus also has an arbitrary Prime Meridian (and presumably Mercury, too), though a very brief look over JPL's website found no analaogus explanation where it was nailed down to be and why.
How about moons?
-------------------- "I was surprised by the matter-of-factness of Kafka's narration, and the subtle humor present as a result." (Sizer 2005)
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posted
There's one advantage Trek enjoys over the real world of space exploration. In Trek, there exists a universal timebase of some sort.
So it might be simple enough to set a standard meridian for planets that don't have a "native" one (i.e. one agreed on by native inhabitants). Just say that the meridian from which the local star is in zenith when it's 1200 hours on June 24th (or whatever) in Greenwich, Earth, becomes the zero meridian of the said planet. For moons, pick the meridian from where the local planet is in zenith at a suitable moment, etc.
Then apply a spherical coordinate grid, using something like the arithmetic mean of radii as the "sea level" reference instead of playing with geoids. And always choose north using the Sol system as the model: when viewed from north, the planets must orbit (and usually also rotate) counterclockwise. These two bits can be used even if one doesn't have Trek's universal timebase.
posted
A 2-d system like we currently use would not be enough for the transporter to work. A 2-D system could put the away team many kilometers above or below the surface. A 3-D system is the obvious choice, and as such a coordinate system is achieved--- what one calls east and west in this system is probably not of consequence. 0 is center of the planet [this is determind just as current planetary studies use spheroid grids on non-spheroids].
Of course, the more I think about it the more I see a relative heading being used. 0 mark 0 in space is a heading towards the center of the galaxy. Maybe if we were to say that any point on a planet is x,y,z from the northern pole where:
X: is the azmuth degree on which the position falls from the north pole [this of course requires that the ship "create" a coordinate system, unless of course the magnetic fields provide one?].
Y: is the distance from the north pole.
Z: is the distance from the planet's center.
On previously unexplored or uncharted planets, the computer will randomly assign the necessary values for the crew to do their work--- whether this sticks is a matter of debate.
-------------------- Later, J _ _ _ _ _ ___ _ _ _ _ _ The Last Person to post in the late Voyager Forum. Bashing both Voyager, Enterprise, and "The Bun" in one glorious post.
posted
Both magnetic and gravitational fields on planets are constantly in flux - especially on Earth-type planets with a molten core. Selecting a point based on a dynamic variable isn't terribly smart.
But yeah, for Trek stuff a three-coordinate system would be most beneficial for what they do. I'd suggest a point relative to an arbitrary dataum, say, based on the intersection of the planet's equator with the the longitude corresponding to the landing party's first touchdown, and then calculating a 3-D coordinate grid from there.
Another coordinate would likely have to be used for transporting - orientation. We've seen that a given ship will orbit the planet at almost any orientation to a given planet, however when you beam something down it *should* materialize right-side up. Odds are that this is a variable built-in to transporter coordinates, that will change even if the target object doesn't move. No wonder that maintaining a transporter lock isn't exactly a piece of cake...
posted
Tom: which moons? Just those of Mars, or moons in general?
Though I'm not quite up for the search at the moment, you could probably get a fair idea of how it's done via Galileo, which has presumably sketched out some kind of basic coordinate system for Europa. Beyond that, maybe someone should just e-mail the Cassini people and ask how they're planning on doing it for Titan.
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quote:Originally posted by Mark Nguyen: Both magnetic and gravitational fields on planets are constantly in flux
Good point...I thought about that after I posted the message. Then again, as I said it was just an example of the kind of ruleset one could use for making such a determination.
-------------------- "Well, I mean, it's generally understood that, of all of the people in the world, Mike Nelson is the best." -- ULTRA MAGNUS, steadfast in curmudgeon
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