gistfile1.txt

from matplotlib import pyplot
from matplotlib.patches import Circle
from shapely.geometry import Polygon, LineString
from descartes.patch import PolygonPatch
import math
import numpy as np

COLOR = {
    True:  '#6699cc',
    False: '#ff3333'
    }

fig = pyplot.figure(1, dpi=90)
# 3: invalid polygon, ring touch along a line
ax = fig.add_subplot(121)

def v_color(ob):
    return COLOR[ob.is_valid]

def plot_coords(ax, ob):
    x, y = ob.xy
    ax.plot(x, y, 'o', color='#999999', zorder=1)

def plot_line(ax, ob):
    x, y = ob.xy
    ax.plot(x, y, color=v_color(ob), alpha=0.7, linewidth=3, solid_capstyle='round', zorder=2)

ext = [(0, 0), (0, 11), (10, 11), (10, 0), (0, 0)]
polygon = Polygon(ext)

plot_coords(ax, polygon.exterior)

patch = PolygonPatch(polygon, facecolor=v_color(polygon), edgecolor=v_color(polygon), alpha=0.5, zorder=2)
ax.add_patch(patch)

ax.set_title('a) valid')

xrange = [-1, 11]
yrange = [-1, 12]
ax.set_xlim(*xrange)
ax.set_xticks(range(*xrange) + [xrange[-1]])
ax.set_ylim(*yrange)
ax.set_yticks(range(*yrange) + [yrange[-1]])
ax.set_aspect(1)

polygon.boundary.

line = LineString([(0.5,0), (0.5,15)])
p = []
plot_line(ax, line)

done = False
# while not done:
for x in range(1, 10):
    b = line.parallel_offset(x * 1.0, 'right')
    print polygon.intersection(b)
    plot_line(ax, b)

pyplot.show()

def distance(p1, p2):
  a = p2[0] - p1[0]
  b = p2[1] - p1[1]
  return math.sqrt(a ** 2 + b ** 2)

def find_next_point_in_direction(current_point, lines):
  pass

def find_next_point_along_line(current_point, line):
  pass

def decompose(polygon, s_pos=(0,0),
                       width=1.5,
                       direction=0.0,
                       seperation=1.0,
                       turn_radius=1.0):
  """
  Direction = radians (0 = east, 90 = north)
  Seperation = distance
  """
  (xa, ya) = polygon.exterior.coords.xy
  (xb, yb) = polygon.exterior.coords.xy
  xb = np.roll(xb, -1)
  yb = np.roll(yb, -1)
  longest_length = 0.0
  longest = None
  for (p1, p2) in zip(zip(xa, ya), zip(xb, yb)):
    dist = distance(p1, p2)
    if longest_length < dist:
      longest = (p1, p2)
      longest_length = dist

  print longest_length
  print longest
  # grow in which direction?
  print
  first_point = (np.min(polygon.exterior.coords.xy[0]), np.min(polygon.exterior.coords.xy[1]))
  print first_point

decompose(polygon)