"""Collections of linestrings and related utilities."""
import shapely
from shapely.errors import EmptyPartError
from shapely.geometry import linestring
from shapely.geometry.base import BaseMultipartGeometry
__all__ = ["MultiLineString"]
class MultiLineString(BaseMultipartGeometry):
"""A collection of one or more LineStrings.
A MultiLineString has non-zero length and zero area.
Parameters
----------
lines : sequence
A sequence LineStrings, or a sequence of line-like coordinate
sequences or array-likes (see accepted input for LineString).
Attributes
----------
geoms : sequence
A sequence of LineStrings
Examples
--------
Construct a MultiLineString containing two LineStrings.
>>> from shapely import MultiLineString
>>> lines = MultiLineString([[[0, 0], [1, 2]], [[4, 4], [5, 6]]])
"""
__slots__ = []
def __new__(self, lines=None):
"""Create a new MultiLineString geometry."""
if not lines:
# allow creation of empty multilinestrings, to support unpickling
# TODO better empty constructor
return shapely.from_wkt("MULTILINESTRING EMPTY")
elif isinstance(lines, MultiLineString):
return lines
lines = getattr(lines, "geoms", lines)
subs = []
for item in lines:
line = linestring.LineString(item)
if line.is_empty:
raise EmptyPartError(
"Can't create MultiLineString with empty component"
)
subs.append(line)
if len(lines) == 0:
return shapely.from_wkt("MULTILINESTRING EMPTY")
return shapely.multilinestrings(subs)
@property
def __geo_interface__(self):
"""Return a GeoJSON-like mapping interface for this MultiLineString."""
return {
"type": "MultiLineString",
"coordinates": tuple(tuple(c for c in g.coords) for g in self.geoms),
}
def svg(self, scale_factor=1.0, stroke_color=None, opacity=None):
"""Return a group of SVG polyline elements for the LineString geometry.
Parameters
----------
scale_factor : float
Multiplication factor for the SVG stroke-width. Default is 1.
stroke_color : str, optional
Hex string for stroke color. Default is to use "#66cc99" if
geometry is valid, and "#ff3333" if invalid.
opacity : float
Float number between 0 and 1 for color opacity. Default value is 0.8
"""
if self.is_empty:
return "<g />"
if stroke_color is None:
stroke_color = "#66cc99" if self.is_valid else "#ff3333"
return (
"<g>"
+ "".join(p.svg(scale_factor, stroke_color, opacity) for p in self.geoms)
+ "</g>"
)
shapely.lib.registry[5] = MultiLineString