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Alien Charting Notation

Mår Ekkertsen

Peer of the Realm
I am trying to work out an (x,y) notation based on a reference planet that still fits hex paper well. Has anyone done this?

The concept is that a scout unit in my alternate Traveller universe made contact with an alien culture using such a reference system. The merchants breaking into the early trade opportunities will have to wrestle with this new navigational notation.
What rule system are you using? The following is from CT canon. And is also at COTI under library data.

The science of mapping interstellar space. Basic to any science of mapping is a coordinate system. The system used by the imperium is based on rings of longitude, rays of latitude, and parsecs. Rays of latitude extend from the galactic core, while concentric rings of longitude are placed at one parsec intervals. By convention, the concentric ring passing through Reference/Capital is labelled the 10,000th ring, and is used as a baseline. Similarly, the ray of latitude extending from the center of the Galaxy through Reference/Capital is designated as the first ray. Measurement is in parsecs, counting in the trailing direction. Computation reveals that the circumference of the 10,000th ring (r=10,000) is 62,832 parsecs. Counting spinward uses a subtraction from 62,833, which is the equivalent of the zero baseline.

For example, Regina, of the Regina Subsector, in the Spinward Marches, is 9930 ring/ray 62723. The format for expression of location is xxxx ring/ray yyyyy, where xxxx is the ring of longitude (distance from the galactic core in parsecs), and yyyyy is the distance of the ray of latitude (in parsecs) from the first ray of lati­tude, measured along the ring of longitude in the trailing direction.

This mapping system is highly lmperio-centric, and other systems are used by other peoples and races outside the imperium. This system has gained wide accep­tance, however, among imperium dominated client-states, human and otherwise. This mapping system breaks down and is prone to error beyond certain limits. it does serve admirably for a band approximately 400 parsecs wide at a longitude of 10,000 parsecs.

Authority: SUPP-8

You could just adjust this for YTU or maybe have something weird. Like instead of seeing the universe as flat (as humans tend to) they might map its height or density etc.

Originally posted by TheRaptor:
Astrography...location is xxxx ring/ray yyyyy....
I do recall the old Reference, reference. Ring/Ray would work but I was hoping someone had worked out a point notation that worked on hex.
You can use an X/Y coordinate system for Hex grids. Infact there are two or three ways of doing so, depending upon how much work you want to do.

1) Assuming the hexes are running vertically, that is the hexes are in columns, the X coordinate becomes how many columns over from the left side of the page. The Y coordinate is the number of hexes from the top (or bottom depending), it just that the Y coordinates are offset by half a hex. Look at the subsector map on p439. The hex numbers are xxyy. Extend to a size as large as needed.

2) The old Greyhawk map used this method: number the columns across the top of the map as 01, 02, etc. Then label the hexes down the left side of the map and across the bottom as A-Z, AA-ZZ, etc. When you select your hex, note the number at the top of the column and then follow the line of adjcent hexes down and to the right until you get a letter(s). The location then becomes AA04 or some such item.
I have decided that the players are unfamiliar enough with the ring /ray notation that I can use it. I’ll modify the origin to the home world of my alien culture.

I wonder now, has anyone done the math for navigation with the ring/ray notation? Something like given x ring/ray y and a ring/ray b the distance is g parsecs.

I have the following C# program to illustrate the simple generation of ring/ray out to ring 6:
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">// x ring/ray y
using System;

class MainApp {
public static void Main() {
int x = 1;
while (x <= 6) {
int y = 1;
while (y <= (x * 6)) {
Console.WriteLine("{0} ring/ray {1}", x, y);
</pre>[/QUOTE]Output Snip
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">1 ring/ray 1
1 ring/ray 2
1 ring/ray 3
1 ring/ray 4
1 ring/ray 5
1 ring/ray 6
2 ring/ray 1
2 ring/ray 2
2 ring/ray 3
2 ring/ray 4
2 ring/ray 5
2 ring/ray 6
2 ring/ray 7
2 ring/ray 8
2 ring/ray 9
2 ring/ray 10
2 ring/ray 11
2 ring/ray 12
3 ring/ray 1
3 ring/ray 2
3 ring/ray 3
3 ring/ray 4
3 ring/ray 5
…</pre>[/QUOTE]What do you think? Is there some simple math I'm missing?
There are two fundamental ways of identifying points in 3space - either cartesian (x,y,z) or Polar (angle, angle, distance). Converting to a 2D map, drop z and the middle angle.

Any highschool book should give you distance equations for polar co-ordinates. From first principles, in 2 space, think of it as a triangle where you have two of the sides (ie the two distances) and the angle between them (subtract your two angles)

For easy math, convert to a pair of right triangles with the right angle coming up from the long side to meet the short side point.

I was about to start writing out formulae, but that isn;t what you want is it - the easy way to do things is draw your map without co-ordinates (but making sure stars are roughly "parsec unit" apart - chose your "central point" and then measure.

If you want to make life hard for them, convert to a different base (base 13 for example) and give them the answers in "Characters" rather than actual numbers. Also include some things that aren't relevant (ie each star has a series of five co-ordinates, angle, distance, size, main colour and political leaning). Measure the angle in an uncommon unit (ie mils or Radians).

It all depends how much work you what the players to do - and their background. Don;t set the bar too high, it's discouraging.
Originally posted by The Mink:
Any highschool book should give you distance equations for polar co-ordinates.

That would all be fine if the ring/ray system was truely polar. If you take out a sheet of hex paper and number the rings out to ring 6 you will quickly see they aren't really polar coordinates at all. :(

Thus my difficulty.
Originally posted by The Mink:
If you want to make life hard for them, convert to a different base (base 13 for example) and give them the answers in "Characters" rather than actual numbers.
Okay. Now I see how evil I could be, as influenced by 'The Mink'. Still I'm trying to work out something plausible but alien to the characters. Perhaps I'll have to dump the hex grid once and for all and go back to the (x,y) point notation. (But in base 36--gotta keep it close to the D6 don't I? ;)

The more I look at the ring/ray notation the less I wonder that nobody I know ever tried to use the Reference system.
A three-coordinate system works well for a hex grid; call the three coordinates "angle" (a), "distance" (d), and "offset" (o). A location is given as {a,d,o}; the origin is always {0,0,0}.

Angle is a number 1 to 6; it represents which line of side-adjacent hexes you're following; direction 1 is coreward, and the direction increment clockwise.

Distance is the number of hexes away from origin.

Offset is tricky - it's how far away from the direct line the world is, at the indicated distance. The direction you count offset in is always clockwise from the direction line; to determine what the correct distance is, you need to remember that for any {a,d,o}, the coordinate {a,d,d} is the same as {a+1,d,0} - in other words, you always count along a line that would form an equilateral triange with the target on one edge, and the origin of the system at the opposite angle.

I have to run out the door; look for another message in a couple or three hours with some examples.
I Originally posted:
I have to run out the door; look for another message in a couple or three hours with some examples.
And herewith the examples:

Let's assume that Darrian (Daryen) (Spinward Marches 0627) is our origin. Darrian is {0,0,0} by definition.

Some of the other worlds in the Darrian subsector would be located as follows:

  • Spume {2,1,0}</font>
  • Mire {6,1,0}</font>
  • Roget {5,2,1}</font>
  • Stern-Stern {6,6,2}</font>
  • Zamine {6,7,5}</font>
  • Torment {1,7,1}</font>
  • Cunnonic {1,6,2}</font>