在Python 3中导入Rosbag

Question

我正在尝试读取Python 3中的rosbag文件。

我安装了ROS2 (Eloquent Elusor)，它应该支持Python3。

当我跑的时候

import rosbag
bag = rosbag.Bag('test.bag')

从Python 2.7开始，它就可以工作了。

当我在Python 3中尝试同样的方法时，我得到：

ModuleNotFoundError: No module named 'rosbag'

我也尝试过像sudo apt install python-rosbag、sudo apt install python3-rospkg和pip3 install rospkg这样的东西，但它们都无济于事。

要从Python 3打开rosbag文件，我应该怎么做？

编辑

这是调用pip3 install rospkg后的输出

Requirement already satisfied: rospkg in ./rosbag-env/lib/python3.6/site-packages
Requirement already satisfied: catkin-pkg in ./rosbag-env/lib/python3.6/site-packages (from rospkg)
Requirement already satisfied: distro in ./rosbag-env/lib/python3.6/site-packages (from rospkg)
Requirement already satisfied: PyYAML in ./rosbag-env/lib/python3.6/site-packages (from rospkg)
Requirement already satisfied: pyparsing in ./rosbag-env/lib/python3.6/site-packages (from catkin-pkg->rospkg)
Requirement already satisfied: python-dateutil in ./rosbag-env/lib/python3.6/site-packages (from catkin-pkg->rospkg)
Requirement already satisfied: docutils in ./rosbag-env/lib/python3.6/site-packages (from catkin-pkg->rospkg)
Requirement already satisfied: six>=1.5 in ./rosbag-env/lib/python3.6/site-packages (from python-dateutil->catkin-pkg->rospkg)

Answer 1

您可以使用bagpy包读取Python语言中的.bag文件。它可以使用pip安装。

pip install bagpy

简要文档请访问https://jmscslgroup.github.io/bagpy/

以下是示例代码片段：

import bagpy
from bagpy import bagreader

b = bagreader('09-23-59.bag')

# get the list of topics
print(b.topic_table)

# get all the messages of type velocity
velmsgs   = b.vel_data()
veldf = pd.read_csv(velmsgs[0])
plt.plot(veldf['Time'], veldf['linear.x'])

# quickly plot velocities
b.plot_vel(save_fig=True)

# you can animate a timeseries data
bagpy.animate_timeseries(veldf['Time'], veldf['linear.x'], title='Velocity Timeseries Plot')

Answer 2

您可以将特定于ROS的PyPI索引用于rosbag和其他ROS Python包：

pip install rosbag --extra-index-url https://rospypi.github.io/simple/

如果您已经将其/opt/ros/$ROS_DISTRO/setup.bash包添加到PYTHONPATH中，那么您可能还需要首先执行unset PYTHONPATH。

您还可以安装支持LZ4压缩的roslz4。

Answer 3

我已经编写了一个纯python3模块来导入rosbag数据。它是独立的--不需要安装ROS。它只适用于选定的消息类型子集，但它应该作为一个示例，您可以按照该示例解压您感兴趣的消息类型：https://github.com/event-driven-robotics/importRosbag