def _add_loop_to_geometry(geometry, multi_line_string):
line_loop = []
for line_index, line_string in enumerate(multi_line_string):
arc = []
for index in range(len(line_string) - 1):
x1 = line_string[index]
x2 = line_string[index + 1]
arc.append(geometry.add_line(x1, x2))
num_lines = len(multi_line_string)
next_line_string = multi_line_string[(line_index + 1) % num_lines]
x1 = line_string[-1]
x2 = next_line_string[0]
arc.append(geometry.add_line(x1, x2))
geometry.add_physical(arc)
line_loop.extend(arc)
return geometry.add_line_loop(line_loop)
def collection_to_geo(collection, lcar=10e3):
r"""Convert a GeoJSON FeatureCollection into pygmsh geometry that can then
be transformed into an unstructured triangular mesh"""
collection = normalize(collection)
features = collection["features"]
geometry = pygmsh.built_in.Geometry()
points = [[[
geometry.add_point((point[0], point[1], 0.0), lcar=lcar)
for point in line_string[:-1]
] for line_string in feature["geometry"]["coordinates"]]
for feature in features]
line_loops = [
_add_loop_to_geometry(geometry, multi_line_string)
for multi_line_string in points
]
plane_surface = geometry.add_plane_surface(line_loops[0], line_loops[1:])
geometry.add_physical(plane_surface)
return geometry