> > Overlaps, Fully Enclosed Within, Encloses, Fully Outside Of, Near, in
> > addition to the normal range attributes <,>,etc), and the "within"
> Interesting. In a recent message, Rob proposed that "overlaps" should
> be expressed as a relation _modifier_, "partial", that goes with
> "within". But this list of others suggests that it should indeed be
> its own separate relation. Funny how the lines between things like
> relations and relation modifiers always get blurry, isn't it?
My rationals is that we save relations by moving the degree of
withinness/enclosesness into a modifier.
My non GEO centric explanation:
Term and Data can be: point, line, area, volume
(0 through 3 dimensions)
Any of the types can be within itself or any of later types. Eg, you
could ask if a point is within a volume, if a line is within an area, of
if an area is within another area.
The server needs to be able to distinguish these, and Mike's proposal of
relation modifiers to describe the nature of the term seems to work well.
So we need a relation for going upwards, and a relation for going
downwards... a point can be _within_ a line, a volume can _enclose_ a
Now, if we're not talking about points, then there may be some part which
is without and some within. A line could extend from inside a volume out
of it, so the line is within/partial the volume. Equally, the volume then
encloses/partial the line. Imagine a toffee apple.
We could also extend the model out to 4 dimensions for timespace -- One
could define the temporal and spatial boundaries of the 100 years war, and
then query to see if a battle is within that time and space.
Fully Outside Of is just NOT within/partial (eg it is not the case that
any point of the line is within the volume). You could also do not
encloses/partial, not within and not encloses.
I've yet to see a kind word spoken of Near as the definition of what is
near is up to the server, so I don't believe that we need to concern
ourselves with it.
,'/:. Rob Sanderson ([log in to unmask])
,'--/::(@)::. Special Collections and Archives, extension 3142
,'---/::::::::::. Twin Cathedrals: telnet: liverpool.o-r-g.org 7777
____/:::::::::::::. WWW: http://liverpool.o-r-g.org:8000/
I L L U M I N A T I