Hi,

On Thu, 09 Mar 2006 00:01:32 -0500
Yavuz Onder wrote:
>
> I noticed that the buildings in Manhattan as an assembly are shifted to
> east so that a lot of them is in the East River, as well quite a few of
> high buildings are in Central Park.

This is very well known; you'll find this sort of thing all over the FG
world.  Earlier this evening, I "flew" over the buildings in Rosslyn, VA,
part of the approach to Washington National Airport (KDCA); half the
buildings are out in the river.

There are two reasons why this occurs.

The first reason for it is that structures like the buildings in downtown
U.S. areas come from databases such as the FAA's Digital Obstruction
File, which gives the locations, heights, and types of potential flight
obstructions (like buildings).  The locations given in such databases
tend to be uncertain; those uncertainties tend not to be *that* bad for
stuff that's very near an airport or in a densely populated area, but
they're there.

The second (and more important in your example) problem is that the
landcover information also comes from databases, and in the case of
features like rivercourses (e.g. the East River) and land usage (e.g.
Central Park), the databases have poor resolution and can be off by
a lot.  As an example, use the UFO to hover on the tallest building
currently sitting in the East River.  From the property browser, get
your latitude and longitude.  Head off to Mapquest or Google Maps and
get a map of that location.  You'll find it corresponds to East 47th
Street and United Nations Place -- the United Nations, in other
words.

So in other words, the problem is not that the buildings are in the
wrong location; the problem is that the land, the rivers, the parks,
etc., are.

There are various ways people are going at fixing this problem; they
all boil down to feeding better data to the software that generates
FlightGear's terrain.  There are better publicly available datasets
than the ones currently used, but it's a bit tricky getting them to
work without creating terrain so dense in polygons that framerates
drop through the floor.  An approach in progress is to create and
maintain a terrain database, where people can submit changes to
correct for things like rivercourses and land usage types; those
improvements would then go into subsequent scenery generation as
part of the inputs data.  For more on this, see 

http://www.custom-scenery.org/Home.223.0.html

and various posts in the archives of this mailing list.


> Also the Brooklyn Bridge is
> completely missing (sunk, or not modeled?).

Not modelled.  If you want to model it, jump in!  You can try the
FG wiki for modelling tips; when done, consider submitting it to the
Flightgear Scenery Object Database so it can be included in the
world scenery and others can admire your work.

http://www.seedwiki.com/wiki/flight_gear/
http://fgfsdb.stockill.org/


> Also, is there a bug reporting system for FG in place? I could not see
> any mention of it at the web site.

There isn't a formal bug tracking system at present.  FG usage is at
the point where I think it's absolutely essential; but it's easy for
me to say.  Someone has to do the actual work of maintaining it, and
that's a serious commitment.

Cheers,

-c


-- 
Chris Metzler                   [EMAIL PROTECTED]
                (remove "snip-me." to email)

"As a child I understood how to give; I have forgotten this grace since I
have become civilized." - Chief Luther Standing Bear

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