def vwr(self, attr):
'''Return the Visvalingam-Whyatt results, optionally
including the triangular area (in meters) as
attribute attr to each simplified point.
'''
pts, r = self.pts, self.r
# double check the minimal triangular area
assert min(t2.h2 for t2 in r) > self.s2 > 0
if attr: # return the trangular area (actually
# the sqrt of double the triangular area)
# converted back from degrees to meter
if isNumpy2(pts):
raise AttributeError('%r invalid' % (attr,))
m = radians(1.0) * self.radius
r[0].h2 = r[-1].h2 = 0 # zap sentinels
for t2 in r: # convert back to meter
setattr(pts[t2.ix], attr, sqrt(t2.h2) * m)
# double check for duplicates
n = len(r)
r = dict((t2.ix, True) for t2 in r)
assert len(r) == n
return self.points(r)
def __init__(self, points, tolerance, radius, shortest, indices,
**options):
'''New C{Simplify} state.
'''
n, self.pts = len2(points)
if n > 0:
self.n = n
self.r = {0: True, n - 1: True} # dict to avoid duplicates
if isNumpy2(points) or isTuple2(points): # NOT self.pts
self.subset = points.subset
if indices:
self.indices = True
if radius:
self.radius = float(radius)
if self.radius < self.eps:
raise ValueError('%s too small: %.6e' % ('radius', radius))
if options:
self.options = options
# tolerance converted to degrees squared
self.s2 = degrees(tolerance / self.radius)**2
if min(self.s2, tolerance) < self.eps:
raise ValueError('%s too small: %.6e' % ('tolerance', tolerance))
self.s2e = self.s2 + 1 # sentinel
# compute either the shortest or perpendicular distance
self.d2i = self.d2iS if shortest else self.d2iP # PYCHOK false
def points(self, r):
'''Return the list of simplified points or indices.
'''
r = sorted(r.keys())
if self.indices:
return list(r)
elif isNumpy2(self.pts) or isTuple2(self.pts):
return self.pts.subset(r)
else:
return [self.pts[i] for i in r]
def points2(points, closed=True, base=None, Error=PointsError):
'''Check a path or polygon represented by points.
@arg points: The path or polygon points (C{LatLon}[])
@kwarg closed: Optionally, consider the polygon closed,
ignoring any duplicate or closing final
B{C{points}} (C{bool}).
@kwarg base: Optionally, check all B{C{points}} against
this base class, if C{None} don't check.
@kwarg Error: Exception to raise (C{ValueError}).
@return: A L{Points2Tuple}C{(number, points)} with the number
of points and the points C{list} or C{tuple}.
@raise PointsError: Insufficient number of B{C{points}}.
@raise TypeError: Some B{C{points}} are not B{C{base}}
compatible.
'''
n, points = len2(points)
if closed:
# remove duplicate or closing final points
while n > 1 and points[n - 1] in (points[0], points[n - 2]):
n -= 1
# XXX following line is unneeded if points
# are always indexed as ... i in range(n)
points = points[:n] # XXX numpy.array slice is a view!
if n < (3 if closed else 1):
raise Error('too few %s: %s' % ('points', n))
if base and not (isNumpy2(points) or isTuple2(points)):
for i in range(n):
base.others(points[i], name='%s[%s]' % ('points', i))
return Points2Tuple(n, points)