Source code for shapelib.utils.line_utils

import numpy as np
from shapely.geometry import LineString, Point




def get_perpendicular_lines(
    line: LineString,
    perpendicular_line_length: float = 0.5,
    distance_between_points: float = 0.02,
    distance_between_neighbors: float = 0.3,
) -> list[LineString]:
    """
    This function returns a list of perpendicular lines to the input line.

    Args:
    -----
    line: LineString
        The input line given by the user.
    perpendicular_line_length: float
        The length of the perpendicular lines.
    distance_between_points: float
        The distance between the points of the given line to be used as reference
        to create the perpendicular lines.
    distance_between_neighbors: float
        The distance between the current point and its neighbors to be used as
        reference to create the perpendicular lines.
    """

    current_distance = distance_between_points
    perpendicular_lines = []

    while current_distance < line.length:
        current_point = line.interpolate(current_distance)
        current_distance += distance_between_points

        left_neighbor = line.interpolate(max(0, current_distance - distance_between_neighbors))
        right_neighbor = line.interpolate(min(line.length, current_distance + distance_between_neighbors))

        current_point_angle = np.arctan2(right_neighbor.y - left_neighbor.y, right_neighbor.x - left_neighbor.x)
        delta_x = perpendicular_line_length * 0.5 * np.sin(current_point_angle)
        delta_y = perpendicular_line_length * 0.5 * np.cos(current_point_angle)

        point1 = Point([current_point.x - delta_x, current_point.y + delta_y])
        point2 = Point([current_point.x + delta_x, current_point.y - delta_y])

        perpendicular_lines.append(LineString([point1, point2]))

        current_distance += distance_between_points

    return perpendicular_lines