Magnetic declination being "the direction of the horizontal component of
the magnetic field measured clockwise from north" according to
MagneticField(1), it must be substracted, not added, from true bearings
in order to obtain the corresponding magnetic bearings.
Example illustrating the bug:
Start at KSFO, open Equipment -> GPS Settings, enter KHTH as the
destination and click on "Search". Before the bug fix, the dialog
gives a bearing of 85, whereas the correct magnetic bearing is 58.
Digging a bit further, the true bearings/azimuths for the shortest
path (geodesic line) from KSFO to KHTH are approx. 71.5 at KSFO and
73.8 at KHTH. This can be verified with two independent libraries
(GeographicLib and PROJ.4):
% echo "37d37'08N 122d22'30W 38d32'45N 118d38'00W" | \
GeodSolve -i
71.44943076 73.75785283 343987.398
% echo "37d37'08N 122d22'30W 38d32'45N 118d38'00W" | \
geod +ellps=WGS84 -I -f '%0.3f'
71.449 -106.242 343987.398
(-106.242 + 180 = 73.758: -106.242 is the "back azimuth" at KHTH for
this path)
The bearing of 85 given by the code in gui/dialogs/gps.xml before
this commit is indeed 71.5 + magnetic declination at the starting
point (KSFO), whereas it should be 71.5 - magnetic declination.
Another, more experimental way:
Start FlightGear with:
fgfs --aircraft=ufo --disable-real-weather-fetch \
'--metar=KSFO 070956Z 36000KT 10SM FEW023 11/07 A2977 RMK AO2 SLP080 T01060067' \
--lat=37.61867421 --lon=-122.37500761 --heading=71.45931
(just in case wind influences the ufo, I have no idea whether this is
the case or not...)
During your flight, progressively increase your heading (as seen in
the HUD, i.e., true heading) so that it smoothly changes from 71.5 at
KSFO to 73.8 at KHTH. You should arrive pretty close to KHTH, whereas
the initial heading of 85 given by the GPS Settings dialog is way too
high, be it interpreted as a magnetic heading (which was visibly the
intention---it would be nice to write that in the dialog BTW) or as a
true heading (in which case the result is even further from the
correct value).
- Small update to the main hydrodynamics system.
- Added initial versions of two systems for modelling hydrodynamic planing.
Signed-off-by: Anders Gidenstam <anders@gidenstam.org>
I did quite a lot of work on textures and materials lately and I'd like
to ask if someone could please take a look on it and maybe commit it to
FGDATA if judged positively.
Starting with commit 0da71d2288836df05548f5f343fe3977ebb2955f of my
repository (see
https://github.com/gilbertohasnofb/new-regional-textures/commits/master
) I did:
- improved urban effect for the Latin American city texture
- improved the Mediterranean city texture (and also better urban effect)
- created new textures for asphalt and concrete runways
- created a new industrial texture (as well as winter version and urban
effect)
- created winter versions for European 18th century city and town textures
- applied urban effect to European 18th century city and town textures
- created a new material in which small areas around 80 large cities
around the world in which the street lights have higher density (1000
for mega cities such as NY and Tokyo, 2000 for large cities such as
Munich and Dubai, while keeping the default 10000 for all the rest of
the globe)
I also created a texture with skid marks for Thorsten's new effect, but
we are still working on this one and this may not even be used.
Everything else is ready to go.
I know this is a lot of things to test, and as Thorsten pointed out in
the forum I it would be better if next time I submit my work in several
chunks (which makes testing easier). So I could break this new work like
that if necessary, but here is a reasonable plan for anyone willing to
test it as it is now:
- start at LIRN at noon during summer. Check the new asphalt runway.
Take off fly around the city centre (it's just in front of the airport).
Test the improved European 18th century city and town textures, as well
as the new industrial texture. Change the environment to winter and
check these three textures once again.
- start at KLAX at noon. Check the new concrete runway. Take off, change
the time to midnight and check the street lights (Los Angeles is a "mega
city" so should be very bright).
- start at SBRJ at noon and check the improved Latin American city
texture. Take off, change the time to midnight and check the street
lights (Rio de Janeiro is a "large city" so should be quite bright).
- start at DTTG @ runway 06 and check the town by the left of the
airport for the improved Mediterranean city texture.
Also, there are plenty of screenshots of this work starting with this
post here: http://forum.flightgear.org/viewtopic.php?f=5&t=26031&start=150#p261282
Add generic version of a canvas MFD (based on the F-15)
It has a fairly simple class structure and hopefully is reasonably easy to understand; Thorsten's using it on the Shuttle and Hooray mentioned that it'd be a good idea to make it generic. It provides a device, that has pages and a set of buttons. The set of buttons control the page that is selected (i.e. a menu). Each page has its own set of menus. A menu defines a label and a page that is displayed. I intend to document it on the wiki once its added.
