The Plane2d class has properties that are the origin, x-axis, and y-axis as the 2D coordinate system. In this class that I implemented, the core functions are as follows:
- _get_local_coords_matrix(): This method constructs a matrix that represents the local coordinate system of the plane in terms of homogeneous coordinates
- get_converted_geometry_by_plane(): Converts a geometry from the plane's coordinate system to another
class Plane2d(AxesVisualizer):
def __init__(self, origin: np.ndarray, x_axis: np.ndarray, y_axis: np.ndarray, normalize: bool = True):
self._origin = origin
self._x_axis = x_axis / np.linalg.norm(x_axis) if normalize else x_axis
self._y_axis = y_axis / np.linalg.norm(y_axis) if normalize else y_axis
def _get_local_coords_matrix(self) -> np.ndarray:
"""Returns a local coordinate matrix expressed in homogeneous coordinates
Returns:
np.ndarray: local coordinates of self
"""
return np.array(
[
[self.x_axis[0], self.y_axis[0], self.origin[0]],
[self.x_axis[1], self.y_axis[1], self.origin[1]],
[0, 0, 1],
]
)
def get_converted_geometry_by_plane(self, plane_to_convert: Plane2d, geometry_to_convert: GeometryCollection) -> GeometryCollection:
"""Converts a given geometry from one plane to another
Args:
plane_to_convert (Plane2d): Target plane to convert the coordinate system
geometry_to_convert (GeometryCollection): Geometry of Shapely to convert
Returns:
GeometryCollection: Converted geometry
"""
matrix_to_map_global_coords = np.linalg.inv(self._get_local_coords_matrix())
matrix_to_map_local_coords = plane_to_convert._get_local_coords_matrix() @ matrix_to_map_global_coords
return affinity.affine_transform(
geom=geometry_to_convert,
matrix=[
matrix_to_map_local_coords[0][0],
matrix_to_map_local_coords[0][1],
matrix_to_map_local_coords[1][0],
matrix_to_map_local_coords[1][1],
matrix_to_map_local_coords[0][2],
matrix_to_map_local_coords[1][2],
]
)