def test_simplification_equal_window():
line = [(30, 10), (10, 30), (40, 40), (50, 30)]
simplified_line = simplify(line, 5, 3)
assert len(simplified_line) == 3
assert simplified_line[0] == (30, 10)
assert simplified_line[1] == (10, 30)
assert simplified_line[2] == (50, 30)
def test_simplification_complex_line():
line = [(10, 30), (15, 10), (20, 15), (25, 30), (30, 60), (35, 10), (40, 40)]
simplified_line = simplify(line, 5, 3)
assert len(simplified_line) == 5
assert simplified_line[0] == (10, 30)
assert simplified_line[1] == (15, 10)
assert simplified_line[2] == (25, 30)
assert simplified_line[3] == (30, 60)
assert simplified_line[4] == (40, 40)
def simplify():
parser = argparse.ArgumentParser(
description="Line simplification tool. Accepts WKT ListString on stdin\n"
" and returns simplified WKT LineString on stdout")
parser.add_argument("tolerance",
type=float,
help="Simplification tolerance.")
parser.add_argument("window", type=int, help="Simplification window")
parser.add_argument("--render",
action="store_true",
help="Render line images during processing")
args = parser.parse_args()
print("Type a correct WKT LineString or type Q/q to quit")
while True:
line = input("--> ")
if line.upper().startswith("Q"):
break
try:
line_string = wkt.loads(line)
line_coords = []
for p in line_string.coords:
line_coords.append(p)
simplified_line = psimpl.simplify(line_coords, args.tolerance,
args.window)
simplified_line_string = LineString(simplified_line)
print(simplified_line_string.wkt)
if args.render:
plt.xlim(line_string.bounds[0], line_string.bounds[2])
plt.ylim(line_string.bounds[1], line_string.bounds[3])
fig, axs = plt.subplots(2)
axs[0].plot(
line_string,
alpha=0.7,
linewidth=3,
solid_capstyle="round",
zorder=2,
)
axs[1].plot(
simplified_line_string,
alpha=0.7,
linewidth=3,
solid_capstyle="round",
zorder=2,
)
plt.show()
except Exception as e:
print("Error: {}\n".format(e))
def test_simplification_negative_tolerance():
line = [(30, 10), (10, 30), (40, 40), (50, 30)]
with pytest.raises(ValueError):
simplify(line, -5, 6)
def test_simplification_short_line():
line = [(30, 10), (10, 30), (40, 40), (50, 30)]
simplified_line = simplify(line, 5, 6)
assert len(simplified_line) == 4
def test_simplification_small_window():
line = [(30, 10), (10, 30), (40, 40), (50, 30)]
simplified_line = simplify(line, 5, 2)
assert len(simplified_line) == 4