overlap_lines_buffer.py

import random
from typing import List, Union

import shapely.geometry as geo
from tqdm import tqdm

MultiLineStringType = Union[List[geo.LineString], geo.MultiLineString]


def overlap_lines(
    lines: MultiLineStringType,
    buffer: float,
    min_length: float = 0,
    sort: bool = True,
    shuffle: bool = True,
    cap_style: geo.CAP_STYLE = 1,
    resolution: int = 16,
):
    """
    This function takes a list of lines and adds a visual effect of a
    z-layer to make them look overlapping. It will shuffle inputs by default.
    """
    lines = [l for l in lines if l.length > min_length]
    lines = list(sorted(lines, key=lambda l: l.length, reverse=True)) if sort else lines
    if shuffle:
        random.shuffle(lines)
    last_buffer = lines[0].buffer(buffer, cap_style=cap_style, resolution=resolution)
    geometries = []
    for line in tqdm(lines, desc="Buffering & Unioning"):
        new_geo = line.difference(last_buffer)
        if new_geo.is_empty:
            continue
        line_buffer = line.buffer(buffer, cap_style=cap_style, resolution=resolution)
        last_buffer = last_buffer.union(line_buffer)
        geometries.append(new_geo)

    return geometries