def smarterEndPosition(posn_begin, posn_end):
# instead of targeting arrival airport, target a closer pt just inside the arrival area
(lat_begin, lon_begin, alt_begin) = posn_begin
(lat_end, lon_end, alt_end ) = posn_end
dist_begin_end = gcUtils.gcDistNMile( (lat_begin,lon_begin), (lat_end,lon_end) )
dist_end_smarterend = min(ARRIVAL_RADIUS, dist_begin_end) * ARRIVAL_RADIUS_SHRINKAGE
lat_smarter, lon_smarter = gcUtils.gcPtAtDistance(
(lat_end,lon_end), (lat_begin,lon_begin),
dist_end_smarterend, gcUtils.EARTH_RADIUS_NM )
alt_smarter = ARRIVAL_ALTITUDE
posn_smarterend = (lat_smarter, lon_smarter, alt_smarter)
return posn_smarterend
def directDescend(posn_begin, posn_end, npts, flightModel):
(lat_begin, lon_begin, alt_begin) = posn_begin
(lat_end, lon_end, alt_end) = posn_end
#assert alt_begin >= alt_end
dist = gcUtils.gcDistNMile((lat_begin, lon_begin), (lat_end, lon_end))
slope = (alt_begin - alt_end) / dist
flightModel.setCustomDescentSlope(slope)
return moveAirplane(posn_begin,
posn_end,
npts,
flightModel.customDescentAlt,
flightModel.airspeed,
altMinMax=(alt_end, alt_begin))
def intersectPosition(posn_begin, slope_begin, posn_end, slope_end):
# finds intersection position of 2 lines in the GC path plane between 2 points
(lat_begin, lon_begin, alt_begin) = posn_begin
(lat_end, lon_end, alt_end) = posn_end
dist_begin_to_end = gcUtils.gcDistNMile((lat_begin, lon_begin),
(lat_end, lon_end))
intercept_begin = alt_begin - slope_begin * dist_begin_to_end
intercept_end = alt_end - slope_end * 0.0
dist_intersect, alt_intersect = lineLineIntersectionPt(
slope_begin, intercept_begin, slope_end, intercept_end)
dist_from_begin = dist_intersect
dist_from_end = dist_begin_to_end - dist_from_begin
lat_intersect, lon_intersect = gcUtils.gcPtAtDistance(
(lat_begin, lon_begin), (lat_end, lon_end), dist_from_end,
gcUtils.EARTH_RADIUS_NM)
return (lat_intersect, lon_intersect, alt_intersect)
def classifyZone(posn_begin, posn_end, flightModel):
# classify current position into one of 4 zones; useful for picking a flightpath
(lat_begin, lon_begin, alt_begin) = posn_begin
(lat_end, lon_end, alt_end) = posn_end
dist_to_end = gcUtils.gcDistNMile((lat_begin, lon_begin),
(lat_end, lon_end))
cruise_alt = flightModel.cruiseIntercept
direct_descent_slope = float(alt_begin - alt_end) / dist_to_end
if direct_descent_slope > abs(flightModel.descentSlope):
return 'near-high' # short-range, high-altitude (over/near airport)
elif alt_begin > cruise_alt:
return 'far-high' # long-range, high-altitude
elif cruisePossible(posn_begin, posn_end, flightModel):
return 'far-low' # long-range, low-altitude
else:
return 'near-low' # short-range, low-altitude (no cruise leg)
def positionCruiseEnd(posn_begin, posn_end, flightModel):
# Returns the position directly above the airport (posn_end) if
# the plane cruised there from the current position (posn_begin)
# at *cruise* altitude (not the current altitude)
# Note: plane may climb slowly, reflecting optimal cruise altitude
# varies as plane burns off fuel and gets lighter.
# Why do we need this point? It's useful for defining a line (cruise path)
# that intersects a ascent/descent line from the current position.
# That intersection is where the plane should start cruising.
(lat_begin, lon_begin, alt_begin) = posn_begin
(lat_end, lon_end, alt_end) = posn_end
dist_begin = gcUtils.gcDistNMile((lat_begin, lon_begin),
(lat_end, lon_end))
dist_end = 0.0 # dist to endpoint is 0 when at endpoint
alt_cruise = flightModel.cruiseIntercept
alt_end = flightModel.cruiseAlt(alt_cruise, dist_begin, dist_end)
return (lat_end, lon_end, alt_end)
def moveAirplane(posn_begin,
posn_end,
npts,
altVsDistModel,
airspeedVsAltModel,
altMinMax=None):
# create intermediate position waypoints between two other waypoints
# print "moveAirplane:", posn_begin, "-->", posn_end
(lat_begin, lon_begin, alt_begin) = posn_begin
(lat_end, lon_end, alt_end) = posn_end
dist_begin = gcUtils.gcDistNMile((lat_begin, lon_begin),
(lat_end, lon_end))
if dist_begin < WAYPOINT_ARRIVAL_RADIUS:
return noWaypoints(posn_begin, posn_end, npts, flightModel=None)
pts = gcUtils.gcIntermediate((lat_begin, lon_begin), (lat_end, lon_end),
npts)
# tricky: zip(*pts) unzips intermediate points with format
# [(lat1,lon1),(lat2,lon2),...] into (lat1, lat2...), (lon1, lon2...)
lats, lons = zip(*pts)
dists = [
dist_begin * (1. - frac) for frac in gcUtils.intermediateFracs(npts)
]
alts = [altVsDistModel(alt_begin, dist_begin, d) for d in dists]
if altMinMax:
altMin, altMax = min(altMinMax), max(altMinMax)
alts = [max(altMin, min(altMax, alt)) for alt in alts]
airspeeds = [airspeedVsAltModel(alt) for alt in alts]
lats = tuple(lats) + (lat_end, )
lons = tuple(lons) + (lon_end, )
alts = tuple(alts) + (alt_end, )
airspeeds = tuple(airspeeds) + (airspeedVsAltModel(alt_end), )
waypoints = {
'LatitudeDegrees': lats,
'LongitudeDegrees': lons,
'AltitudeFeet': alts,
'AirspeedKnots': airspeeds
}
return waypoints