Re: [ogpx] URI schema for virtual world locations?

[Carlo Wood <[e-mail]>]

On Sat, Jan 23, 2010 at 01:36:37AM +0100, Carlo Wood wrote:
> It is not true that the relative position of any two arbitrary
> regions is known. For example, some world could consist of
> of planets in solar systems and some would simply be too far
> apart to use coordinates in meters. Another example are
> the islands of private sims in SL.
> 
> Hence, it makes more sense to limit coordinates to a Cartesian
> coordinate system relative to a given region, and be have

and have*

> a public service that maps region name pairs to a relative
> position vector v(name1,name2), or returning nil if they are
> not in the same space.

Later I got back from this idea, see below.

> The distance between {name1, v1}, where v1 = {x1,y1,z1},
> and {name2, v2} is then v(name1, name2) + v2 - v1.

This will thus not be possible (nor needed), see below.

> That way a world is not obliged to have one single space
> where in every region must have a place.
> 
> Also, putting every region in one region will likely

in one space*

> lead to this 2D plane with regions and a z-coordinate
> with a range equal to that of each region: a flat world
> (like SL). I hope everyone knows that ANY example that
> breaks a protocol is prove that the protocol is wrong ;),

proof*

> so here it goes: someone might want to create "ring world"
> (http://en.wikipedia.org/wiki/Ringworld), where the
> rings exists of square regions, and the diameter of the

ring*

> ring is too large to really want to use it. Such a world
> could not very easily map it's world positions to a
> flat one (or even x/y/z, without getting really large

Rather, to a 3D one (regions would be upside down
relative to others).

> and seemingly random numbers).
> 
> A better approach therefore seems to be:
> 
> A Cartesian coordinate system for one region at a time.
> A map from region names to a 2-dimensional *map* coordinates,
> where the map coordinates might have any arbitrary relationship
> to world coordinates (being irrelevant), including the
> notion that two regions might not be in the same space.
> 
> This would allow painting a map on a 2D surface (which can
> be used to explore and retrieve LM's from), but it would
> NOT allow to calculate the (real 3-D space) distance between
> points.
> 
> 1.3. there may be two forms of location representation:
> map position (longitude/latitude) that give regions in a
> given space, a place on a map, and cartesian coordinates
> relative to the origin of a region (x,y,z).
> 
> 
> 1.4. the statement above (1.3) implies there is a public service
> available to map between the {space, longitude, latitude}
> "map coordinates" and points relative to a given region:
> 
> {space, longitude, latitude} <---> {region name, x, y}
> 
> -- 
> Carlo Wood <[e-mail]>

In the case of Second Life, there is only one 'space' (rather,
one map), so 'space' would always be the same value (ie '0').

A different space means a different map, and also that you
can't walk there, only teleport. There is therefore little
difference between two different spaces within one VW (as in
"run by one authority") and two different VW's (that allow
teleporting between them).

-- 
Carlo Wood <[e-mail]>

PS Re RingWorld... it WOULD be kinda cool is you could
   look 2 or three sims far, and anything beyond that
   would be "map"... in a ring :). If you'd look up,
   you'd see the ring, and you could zoom in like on
   a real map (and double click to teleport there).
   Heheh.  That would require some viewer-side support
   though.