gtsam/python/gtsam/utils/plot.py

446 lines
14 KiB
Python

"""Various plotting utlities."""
# pylint: disable=no-member, invalid-name
from typing import Iterable, Optional, Tuple
import matplotlib.pyplot as plt
import numpy as np
from matplotlib import patches
from mpl_toolkits.mplot3d import Axes3D # pylint: disable=unused-import
import gtsam
from gtsam import Marginals, Point3, Pose2, Pose3, Values
def set_axes_equal(fignum: int) -> None:
"""
Make axes of 3D plot have equal scale so that spheres appear as spheres,
cubes as cubes, etc.. This is one possible solution to Matplotlib's
ax.set_aspect('equal') and ax.axis('equal') not working for 3D.
Args:
fignum: An integer representing the figure number for Matplotlib.
"""
fig = plt.figure(fignum)
ax = fig.gca(projection='3d')
limits = np.array([
ax.get_xlim3d(),
ax.get_ylim3d(),
ax.get_zlim3d(),
])
origin = np.mean(limits, axis=1)
radius = 0.5 * np.max(np.abs(limits[:, 1] - limits[:, 0]))
ax.set_xlim3d([origin[0] - radius, origin[0] + radius])
ax.set_ylim3d([origin[1] - radius, origin[1] + radius])
ax.set_zlim3d([origin[2] - radius, origin[2] + radius])
def ellipsoid(rx: float, ry: float, rz: float,
n: int) -> Tuple[np.ndarray, np.ndarray, np.ndarray]:
"""
Numpy equivalent of Matlab's ellipsoid function.
Args:
rx: Radius of ellipsoid in X-axis.
ry: Radius of ellipsoid in Y-axis.
rz: Radius of ellipsoid in Z-axis.
n: The granularity of the ellipsoid plotted.
Returns:
The points in the x, y and z axes to use for the surface plot.
"""
u = np.linspace(0, 2 * np.pi, n + 1)
v = np.linspace(0, np.pi, n + 1)
x = -rx * np.outer(np.cos(u), np.sin(v)).T
y = -ry * np.outer(np.sin(u), np.sin(v)).T
z = -rz * np.outer(np.ones_like(u), np.cos(v)).T
return x, y, z
def plot_covariance_ellipse_3d(axes,
origin: Point3,
P: np.ndarray,
scale: float = 1,
n: int = 8,
alpha: float = 0.5) -> None:
"""
Plots a Gaussian as an uncertainty ellipse
Based on Maybeck Vol 1, page 366
k=2.296 corresponds to 1 std, 68.26% of all probability
k=11.82 corresponds to 3 std, 99.74% of all probability
Args:
axes (matplotlib.axes.Axes): Matplotlib axes.
origin: The origin in the world frame.
P: The marginal covariance matrix of the 3D point
which will be represented as an ellipse.
scale: Scaling factor of the radii of the covariance ellipse.
n: Defines the granularity of the ellipse. Higher values indicate finer ellipses.
alpha: Transparency value for the plotted surface in the range [0, 1].
"""
k = 11.82
U, S, _ = np.linalg.svd(P)
radii = k * np.sqrt(S)
radii = radii * scale
rx, ry, rz = radii
# generate data for "unrotated" ellipsoid
xc, yc, zc = ellipsoid(rx, ry, rz, n)
# rotate data with orientation matrix U and center c
data = np.kron(U[:, 0:1], xc) + np.kron(U[:, 1:2], yc) + \
np.kron(U[:, 2:3], zc)
n = data.shape[1]
x = data[0:n, :] + origin[0]
y = data[n:2 * n, :] + origin[1]
z = data[2 * n:, :] + origin[2]
axes.plot_surface(x, y, z, alpha=alpha, cmap='hot')
def plot_pose2_on_axes(axes,
pose: Pose2,
axis_length: float = 0.1,
covariance: np.ndarray = None) -> None:
"""
Plot a 2D pose on given axis `axes` with given `axis_length`.
Args:
axes (matplotlib.axes.Axes): Matplotlib axes.
pose: The pose to be plotted.
axis_length: The length of the camera axes.
covariance (numpy.ndarray): Marginal covariance matrix to plot
the uncertainty of the estimation.
"""
# get rotation and translation (center)
gRp = pose.rotation().matrix() # rotation from pose to global
t = pose.translation()
origin = t
# draw the camera axes
x_axis = origin + gRp[:, 0] * axis_length
line = np.append(origin[np.newaxis], x_axis[np.newaxis], axis=0)
axes.plot(line[:, 0], line[:, 1], 'r-')
y_axis = origin + gRp[:, 1] * axis_length
line = np.append(origin[np.newaxis], y_axis[np.newaxis], axis=0)
axes.plot(line[:, 0], line[:, 1], 'g-')
if covariance is not None:
pPp = covariance[0:2, 0:2]
gPp = np.matmul(np.matmul(gRp, pPp), gRp.T)
w, v = np.linalg.eig(gPp)
# k = 2.296
k = 5.0
angle = np.arctan2(v[1, 0], v[0, 0])
e1 = patches.Ellipse(origin,
np.sqrt(w[0] * k),
np.sqrt(w[1] * k),
np.rad2deg(angle),
fill=False)
axes.add_patch(e1)
def plot_pose2(
fignum: int,
pose: Pose2,
axis_length: float = 0.1,
covariance: np.ndarray = None,
axis_labels=("X axis", "Y axis", "Z axis"),
) -> plt.Figure:
"""
Plot a 2D pose on given figure with given `axis_length`.
Args:
fignum: Integer representing the figure number to use for plotting.
pose: The pose to be plotted.
axis_length: The length of the camera axes.
covariance: Marginal covariance matrix to plot
the uncertainty of the estimation.
axis_labels (iterable[string]): List of axis labels to set.
"""
# get figure object
fig = plt.figure(fignum)
axes = fig.gca()
plot_pose2_on_axes(axes,
pose,
axis_length=axis_length,
covariance=covariance)
axes.set_xlabel(axis_labels[0])
axes.set_ylabel(axis_labels[1])
return fig
def plot_point3_on_axes(axes,
point: Point3,
linespec: str,
P: Optional[np.ndarray] = None) -> None:
"""
Plot a 3D point on given axis `axes` with given `linespec`.
Args:
axes (matplotlib.axes.Axes): Matplotlib axes.
point: The point to be plotted.
linespec: String representing formatting options for Matplotlib.
P: Marginal covariance matrix to plot the uncertainty of the estimation.
"""
axes.plot([point[0]], [point[1]], [point[2]], linespec)
if P is not None:
plot_covariance_ellipse_3d(axes, point, P)
def plot_point3(
fignum: int,
point: Point3,
linespec: str,
P: np.ndarray = None,
axis_labels: Iterable[str] = ("X axis", "Y axis", "Z axis"),
) -> plt.Figure:
"""
Plot a 3D point on given figure with given `linespec`.
Args:
fignum: Integer representing the figure number to use for plotting.
point: The point to be plotted.
linespec: String representing formatting options for Matplotlib.
P: Marginal covariance matrix to plot the uncertainty of the estimation.
axis_labels: List of axis labels to set.
Returns:
fig: The matplotlib figure.
"""
fig = plt.figure(fignum)
axes = fig.gca(projection='3d')
plot_point3_on_axes(axes, point, linespec, P)
axes.set_xlabel(axis_labels[0])
axes.set_ylabel(axis_labels[1])
axes.set_zlabel(axis_labels[2])
return fig
def plot_3d_points(fignum,
values,
linespec="g*",
marginals=None,
title="3D Points",
axis_labels=('X axis', 'Y axis', 'Z axis')):
"""
Plots the Point3s in `values`, with optional covariances.
Finds all the Point3 objects in the given Values object and plots them.
If a Marginals object is given, this function will also plot marginal
covariance ellipses for each point.
Args:
fignum (int): Integer representing the figure number to use for plotting.
values (gtsam.Values): Values dictionary consisting of points to be plotted.
linespec (string): String representing formatting options for Matplotlib.
marginals (numpy.ndarray): Marginal covariance matrix to plot the
uncertainty of the estimation.
title (string): The title of the plot.
axis_labels (iterable[string]): List of axis labels to set.
"""
keys = values.keys()
# Plot points and covariance matrices
for key in keys:
try:
point = values.atPoint3(key)
if marginals is not None:
covariance = marginals.marginalCovariance(key)
else:
covariance = None
fig = plot_point3(fignum,
point,
linespec,
covariance,
axis_labels=axis_labels)
except RuntimeError:
continue
# I guess it's not a Point3
fig = plt.figure(fignum)
fig.suptitle(title)
fig.canvas.set_window_title(title.lower())
def plot_pose3_on_axes(axes, pose, axis_length=0.1, P=None, scale=1):
"""
Plot a 3D pose on given axis `axes` with given `axis_length`.
Args:
axes (matplotlib.axes.Axes): Matplotlib axes.
point (gtsam.Point3): The point to be plotted.
linespec (string): String representing formatting options for Matplotlib.
P (numpy.ndarray): Marginal covariance matrix to plot the uncertainty of the estimation.
"""
# get rotation and translation (center)
gRp = pose.rotation().matrix() # rotation from pose to global
origin = pose.translation()
# draw the camera axes
x_axis = origin + gRp[:, 0] * axis_length
line = np.append(origin[np.newaxis], x_axis[np.newaxis], axis=0)
axes.plot(line[:, 0], line[:, 1], line[:, 2], 'r-')
y_axis = origin + gRp[:, 1] * axis_length
line = np.append(origin[np.newaxis], y_axis[np.newaxis], axis=0)
axes.plot(line[:, 0], line[:, 1], line[:, 2], 'g-')
z_axis = origin + gRp[:, 2] * axis_length
line = np.append(origin[np.newaxis], z_axis[np.newaxis], axis=0)
axes.plot(line[:, 0], line[:, 1], line[:, 2], 'b-')
# plot the covariance
if P is not None:
# covariance matrix in pose coordinate frame
pPp = P[3:6, 3:6]
# convert the covariance matrix to global coordinate frame
gPp = gRp @ pPp @ gRp.T
plot_covariance_ellipse_3d(axes, origin, gPp)
def plot_pose3(
fignum: int,
pose: Pose3,
axis_length: float = 0.1,
P: np.ndarray = None,
axis_labels: Iterable[str] = ("X axis", "Y axis", "Z axis"),
) -> plt.Figure:
"""
Plot a 3D pose on given figure with given `axis_length`.
Args:
fignum: Integer representing the figure number to use for plotting.
pose (gtsam.Pose3): 3D pose to be plotted.
axis_length: The length of the camera axes.
P: Marginal covariance matrix to plot the uncertainty of the estimation.
axis_labels: List of axis labels to set.
Returns:
fig: The matplotlib figure.
"""
# get figure object
fig = plt.figure(fignum)
axes = fig.gca(projection='3d')
plot_pose3_on_axes(axes, pose, P=P, axis_length=axis_length)
axes.set_xlabel(axis_labels[0])
axes.set_ylabel(axis_labels[1])
axes.set_zlabel(axis_labels[2])
return fig
def plot_trajectory(
fignum: int,
values: Values,
scale: float = 1,
marginals: Marginals = None,
title: str = "Plot Trajectory",
axis_labels: Iterable[str] = ("X axis", "Y axis", "Z axis"),
) -> None:
"""
Plot a complete 2D/3D trajectory using poses in `values`.
Args:
fignum: Integer representing the figure number to use for plotting.
values: Values containing some Pose2 and/or Pose3 values.
scale: Value to scale the poses by.
marginals: Marginalized probability values of the estimation.
Used to plot uncertainty bounds.
title: The title of the plot.
axis_labels (iterable[string]): List of axis labels to set.
"""
fig = plt.figure(fignum)
axes = fig.gca(projection='3d')
axes.set_xlabel(axis_labels[0])
axes.set_ylabel(axis_labels[1])
axes.set_zlabel(axis_labels[2])
# Plot 2D poses, if any
poses = gtsam.utilities.allPose2s(values)
for key in poses.keys():
pose = poses.atPose2(key)
if marginals:
covariance = marginals.marginalCovariance(key)
else:
covariance = None
plot_pose2_on_axes(axes,
pose,
covariance=covariance,
axis_length=scale)
# Then 3D poses, if any
poses = gtsam.utilities.allPose3s(values)
for key in poses.keys():
pose = poses.atPose3(key)
if marginals:
covariance = marginals.marginalCovariance(key)
else:
covariance = None
plot_pose3_on_axes(axes, pose, P=covariance, axis_length=scale)
fig.suptitle(title)
fig.canvas.set_window_title(title.lower())
def plot_incremental_trajectory(fignum: int,
values: Values,
start: int = 0,
scale: float = 1,
marginals: Optional[Marginals] = None,
time_interval: float = 0.0) -> None:
"""
Incrementally plot a complete 3D trajectory using poses in `values`.
Args:
fignum: Integer representing the figure number to use for plotting.
values: Values dict containing the poses.
start: Starting index to start plotting from.
scale: Value to scale the poses by.
marginals: Marginalized probability values of the estimation.
Used to plot uncertainty bounds.
time_interval: Time in seconds to pause between each rendering.
Used to create animation effect.
"""
fig = plt.figure(fignum)
axes = fig.gca(projection='3d')
poses = gtsam.utilities.allPose3s(values)
keys = gtsam.KeyVector(poses.keys())
for key in keys[start:]:
if values.exists(key):
pose_i = values.atPose3(key)
plot_pose3(fignum, pose_i, scale)
# Update the plot space to encompass all plotted points
axes.autoscale()
# Set the 3 axes equal
set_axes_equal(fignum)
# Pause for a fixed amount of seconds
plt.pause(time_interval)