def findCrossings(self, tracks):
"""
Given a series of track points and a longitude, calculate
if the tracks intersect that line of longitude.
:param tracks: collection of :class:`Track` objects
:return: h, ewh, weh, histograms for each line of longitude,
recording the rate of crossings
"""
LOG.debug("Processing %d tracks" % (len(tracks)))
h = np.zeros((len(self.gateLats) - 1, len(self.gateLons)))
ewh = np.zeros((len(self.gateLats) - 1, len(self.gateLons)))
weh = np.zeros((len(self.gateLats) - 1, len(self.gateLons)))
for n, gLon in enumerate(self.gateLons):
gStart = Int.Point(gLon, self.gateLats.max())
gEnd = Int.Point(gLon, self.gateLats.min())
lats = []
ewlats = []
welats = []
for t in tracks:
for i in range(len(t.Longitude) - 1):
cross = Int.Crossings()
start = Int.Point(t.Longitude[i], t.Latitude[i])
end = Int.Point(t.Longitude[i + 1], t.Latitude[i + 1])
r = cross.LineLine(start, end, gStart, gEnd)
if r.status == "Intersection":
lats.append(r.points[0].y)
startSide = Int._isLeft(gStart, gEnd, start)
endSide = Int._isLeft(gStart, gEnd, end)
if ((startSide < 0.) and (endSide >= 0.)) \
or ((startSide <= 0.) and (endSide > 0.)):
welats.append(r.points[0].y)
elif ((startSide > 0.) and (endSide <= 0.)) \
or ((startSide >= 0.) and (endSide < 0.)):
ewlats.append(r.points[0].y)
else:
# Track segment doesn't cross that longitude
continue
# Generate the histograms to be returned:
if len(lats) > 0:
h[:, n], bins = np.histogram(lats, self.gateLats, density=True)
if len(ewlats) > 0:
ewh[:, n], bins = np.histogram(ewlats,
self.gateLats,
density=True)
if len(welats) > 0:
weh[:, n], bins = np.histogram(welats,
self.gateLats,
density=True)
return h, ewh, weh
def processTracks(self, tracks):
"""
Given a collection of :class:`Track` objects and set of gate vertices,
calculate if the tracks cross the gates in either an onshore or
offshore direction.
Returns the histograms for the gate counts.
"""
landfall = []
offshore = []
for t in tracks:
for i in range(1, len(t.Longitude)):
cross = Int.Crossings()
start = Int.Point(t.Longitude[i - 1], t.Latitude[i - 1])
end = Int.Point(t.Longitude[i], t.Latitude[i])
startOnshore = Int.inLand(start, self.coast)
endOnshore = Int.inLand(end, self.coast)
if not startOnshore and endOnshore:
# Landfall:
cross = Int.Crossings()
for j in range(1, len(self.gates) - 1):
r = cross.LineLine(start, end, self.gates[j - 1],
self.gates[j])
if r.status == "Intersection":
landfall.append(j)
elif startOnshore and not endOnshore:
# Moving offshore:
cross = Int.Crossings()
for j in range(1, len(self.gates) - 1):
r = cross.LineLine(start, end, self.gates[j - 1],
self.gates[j])
if r.status == "Intersection":
offshore.append(j)
# Generate the histograms to be returned:
lh, n = np.histogram(landfall,
np.arange(len(self.gates)),
density=True)
oh, n = np.histogram(offshore,
np.arange(len(self.gates)),
density=True)
return lh, oh
def setUp(self):
"""Set up the test environment"""
xverts = [100., 100., 110., 110., 100.]
yverts = [-20., -30., -30., -20., -20.]
self.point1 = Intersections.Point(xverts[0],yverts[0])
self.point2 = Intersections.Point(xverts[1],yverts[1])
self.leftPoint = Intersections.Point( 105., -25. )
self.rightPoint = Intersections.Point( 95., -25. )
self.circleCentre = Intersections.Point( 105., -25. )
self.circleRadius0 = 0.0
self.circleRadius1 = 5.0
self.circleRadius2 = 7.5
self.circleRadius3 = 7.0
self.Crossings = Intersections.Crossings()
self.vertices = Intersections.convert2vertex( xverts, yverts )
