pkg_resources.DistributionNotFound: The 'catkin-pkg==0.4.9' distribution was not found

个人感觉是python2与python3在ros中的差异导致的，

问题一：Traceback (most recent call last):
  File "/usr/bin/rosdep", line 3, in <module>
    from rosdep2.main import rosdep_main

ImportError: No module named 'rosdep2'

解决：sudo apt-get install python3-rosdep

问题二：pkg_resources.DistributionNotFound: The 'catkin-pkg==0.4.9' distribution   was not found

解决：

pip install catkin-tools

pip install rospkg

可参考http://www.cnblogs.com/h46incon/p/6207145.html