Galaxy Scale Mismatch

Hrm... my two sources of data for the Traveller galaxy structure don't quite equate, leading to fairly dramatic mismatches.

If you measure the Local Arm's girth at the Ray 0 i.e. through Reference (Core 0140) on the detailed map from Security Leak by Mike Mikesh, you get a distance of 1600 parsecs. If you measure the distance on the detailed map by Clifford Linehan - which he used to construct the Zhodani Core Route - you get a distance of 1760 parsecs.

Composite of the two maps.

That's about a 10% difference... and it's going to bother me. I dug a bit further and it looks like the Security Leak #5 map is the original source, per this conversation between Marc Miller and Clifford Linehan. Mr. Linehan took Mike Mikesh's original, scanned it, cleaned it up, and handed the results back to MWM who took it under the FFE fold. This would indicate that either Mr. Linehan corrected the size (to fit known dimensions of the galaxy) or accidentally scaled it up. (Charted Space doesn't quite line up either.)

Since Traveller parsecs are based on a hexagonal grid, it's actually easy to introduce an error of around 14% - hexes pack more tightly horizontally than vertically, with a ratio around 0.868. This is factored in when I map from image-space to world-space (and you'll see residue in the API). Here's a sample - the red square is precisely 10 parsecs tall, but more than 11 parsecs wide - yet it's a perfect square if you count the pixels.


If I had to guess, I'd say that one of the two galactic-scale map authors was unaware of this, and and used a horizontally-biased parsec scale for determining the number of sectors between Charted Space and the galactic core.

Bleah. :( Ω

That article on rifts from Security Leak fanzine was too good to pass up, so I've incorporated Mike Mikesh's speculation on the extent of the local rifts. Check it out:


Rift rendering using vectors has been dropped, and it now relies on a bitmap - this gives softer edges which IMHO is an improvement. If you zoom out the rifts gradually fade as they become insignificant relative to the overall Galactic structure. If you zoom in they fade in, then disappear at the same point where the map stops rendering "background" stars - now at 4 pixels/parsec. In between they're quite pretty - and look somewhat like an absorption (or "dark") nebula.

The effect is present but not particularly visible in non-Candy styles as well, most notably now as dark shading in the "Atlas" style which mimics (crudely) the shading of the rifts shown in the Alien Module maps. The edges of the rifts are a bit coarse, and I'll probably tweak them over time.


As always, comments appreciated. Ω