A little clarification on SDF, since it comes up once or twice in this
thread. Jason's earlier descriptions of it's capabilities are pretty good.
It supports multiple Feature Classes / Tables per file, strongly typed
properties, multiple geometry properties per class, with seperate R-Trees
for each geometry property. All of this is stored in a single file that is
heavily optimized for spatial reads. The SDF FDO Provider suppports a
multiple reader / single writer model. The geometries themselves include
simple features + circular arcs in 2D, 2D with Z, 2D with M, or 2D with Z &
M. The R-Trees are currently 2D.
Is it an open format? ABSOLUTELY (we just never wrote a spec, but I am
willing to get it done)
Another little known fact is that in the process of creating SDF we
(Autodesk) literally wrote the code three times. The first time we built SDF
on BerkleyDB, a great open source project but it has some fairly significant
license fees for using it in a proprietary product. The second time we wrote
it on SQLite, however the performance penalaty of the Relational layer was
significant (read orders of magnitude). The third time we chose to strip
away the SQLite relational layer and built directly on the SQLite Backend
components (B-Tree, Pager, and OS Interface). In the end the third
implementation actually turned out to be faster than BDB and is the one we
use today.
All this said, I'd really like to understand everyones requirements for this
new format. If SDF fits thats great, if not thats ok too. We are always
happy to contribute what we can to the community.
Bob
----- Original Message -----
From: "Michael P. Gerlek" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; "OSGeo Discussions" <[email protected]>;
<[EMAIL PROTECTED]>
Sent: Tuesday, November 13, 2007 12:23 PM
Subject: RE: [OSGeo-Discuss] Re: idea for an OSGeo project -- a new,open
data format
> Regarding the suggestion that MapServer takes on this new format as
the
> primary format: I think this is way beyond the scope of what OSGeo
should
> be doing.
I agree with bitnerd. If the MapServer team thinks this is a valuable
and worthwhile format, they will adopt it at some point. It would not
be unreasonable for them to step back and see how thing progresses
before deciding to spend their valuable ergs on it. The burden is on
the "OpenShape" people to show the idea is worthwhile and meritorious.
(My two cents on the "standards" question: OSGeo is not a standards
organization, but / however / on the other hand / nonetheless one of the
reasons OSGeo exists is to foster such collaborations. If some people
want to try and develop something new like this, I'm all in favor of
OSGeo offering mailing list and wiki space to help out. Declaring this
to be a "standard" effort, however, is probably premature in any case --
more useful at this point to see the idea sketched out further, see
who's interested, etc.)
-mpg
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