Attached is a patch to the airport data storage that I would like committed
after review if acceptable. Currently the storage of airports mapped by ID
is by locally created objects - about 12 Meg or so created on the stack if
I am not mistaken. I've changed this to creating the airports on the heap,
and storing pointers to them - see FGAirportList.add(...) in
src/Airports/simple.cxx. I believe that this is probably better practice,
and it's certainly cured some strange problems I was seeing when accessing
the airport data with some gps unit code. Changes resulting from this have
cascaded through a few files which access the data - 11 files are modified
in all. Melchior and Durk - you might want to test this and shout if there
are problems since the metar and traffic code are probably the biggest
users of the airport data. I've also added a fuzzy search function that
returns the next matching airport code in ASCII sequence in order to
support gps units that have autocompletion of partially entered codes.
More generally, the simple airport class seems to have grown a lot with the
fairly recent addition of the parking, runway preference and schedule time
code. It is no longer just an encapsulation of the global airport data
file, and has grown to 552 bytes in size when unpopulated (about 1/2 a K!).
My personal opinion is that we should look to just store the basic data in
apt.dat for all global airports in a simple airport class, plus globally
needed data (metar available?), and then have the traffic, AI and ATC
subsystems create more advanced airports for themselves as needed in the
area of interest. Once a significant number of airports worldwide have
ground networks and parking defined, it will be impractical and unnecessary
to store them all in memory. That's just a thought for the future though.
I just heard from John Wojnaroski that you and he are going to work on getting
a flightgear demo machine up for the linux expo thursday and Friday. John
indicated that he would very much like to get a CVS version with the new
traffic code up and running before the expo.
a single apt.dat.gz file which is in the native X-Plane format.
To do this I wrote a front end loader than builds the airport and runway
list. Some of the changes I needed to make had a cascading effect, so there
are minor naming changes scattered throughout the code.
A good elevation is critical for proper glide slope modeling. This patch
assigns the average field elevation to any ILS component that doesn't have
a valid elevation.
Also, for an ILS approach, use the GS transmitter elevation for glide slope
calculations rather than the localizer elevation, in some cases this can
make a big difference.
These change add some code that at initialization time will snap all
localizers into perfect alignment with their runways. It's my experience
that the DAFIF/FAA data reports runway and localizer headings to a level
of precision that is great for making charts, or adjusting your OBS, etc.
But the level of precision of this data can be far enough off to make you
visibly *un*aligned with the runway when the CDI needle is centered.
There are probably cases where the localizer isn't really perfectly
aligned with the runway, or intentionally misaligned to avoid obstacles
or terrain. So I have made this configurable for those that trust the
data more than I do. Just set "/sim/navdb/auto-align-localizers" to
true/false in the preferences file to turn this feature on or off in the
code.
- FG now directly supports Robin's native nav database file format.
- His latest data now separates out dme, gs, loc, and marker beacon
transmitters rather than lumping them all into a single "ILS" record.
- These new data structure changes prompted me to do some code restructuring
so that internally these different types of navaids are all kept as
separate lists and searched and handled separately.
- This structural change had a cascading affect on any code that
references or uses the nav databases. I've gone and "touched" a lot of
nav related code in a lot of places.
- As an added bonus, the new data (and code) adds DME bias so these will
all now read as they do in real life.
- Added Navaids/navdb.cxx and Navaids/navdb.hxx which provide a front
end loaders for the nav data.
- Added Navaids/navrecord.hxx which is a new "generic" nav data record.
- Removed Navaids/ils.hxx, Navaids/ilslist.cxx, Navaids/ilslist.hxx,
Navaids/mkrbeacons.cxx, and Navaids/mkrbeacons.hxx which are all now
depricated.
