Computing Borders

[inexorabletash]

J. Greely has a utility to generate borders, as input to his map generator:

http://dotclue.org/t20/

(The utility is allygen.)

While pondering what to do for my map site - which right now has large hand-drawn vectors based on the old Imperium Poster - I ran across the Alpha Shapes - generalizations of the concept of a convex hull:

Applet:

http://cgm.cs.mcgill.ca/~godfried/teaching/projects97/belair/alpha.html

Utility:

http://cm.bell-labs.com/netlib/voronoi/hull.html

Basically you can take a set of points compute the Delaunay triangulation of the points, remove any boundary lines that exceed some length, and use the remaining set of boundary lines. This "feels" just right for interstellar mapping - say, with a length of about 5.

There might need to be a way to "repel" from non-members (which Greely's util handles). If I get a chance to play further I'll post results if anyone is interested.

(FWIW, the concept applies to higher dimensions as well, so you could use it for 3D.)

 

[Gruffty]

How bizarre! Josh's post (above) has appeared in the list of "View My Recent Posts" in my profile, i.e. as though I started the topic.

I'd like to reassure everyone, including Josh, that he and I are definitely not one and the same

 

[inexorabletash]

Really? Are you sure? This certainly calls a lot of my assumptions into question.

 

[Gruffty]

Ahhh, there's the nub, methinks

When we "assume", we make an "ass" of "u" and "me"

<scratchscratchscratch>

Of course, if you're girlfriend/wife is better looking than my wife, it's not a problem