How to extract XYZ data from .pcap file

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Hello, I am a complete freshman on Linux, ROS so, don't be mad :). I have a Velodyne VLP16 and the list that I want to with this laser is:

1. Acquire raw data (.pcap)
2. Visualize it using 3D viewer
3. Extract XYZ and Intensity data from acquired raw data

What I accomplished so far is only No.2 using commands below (I downloaded .pcap file from velodyne website):

$ roslaunch velodyne_pointcloud VPL16_points.launch pcap:=/home/soowon/Documents/County_Fair.pcap

$ rosrun velodyne_pointcloud cloud_node _calibration:=/home/soowon/catkin_ws/src/velodyne-master/velodyne_pointcloud/params/VLP16db.yaml

$ rosrun rviz rviz -f velodyne

$ Add -> By topic -> /velodyne_points -> PointCloud2

By commands above, I was able to see pointcloud using RViz. Now here's my questions:

1. I followed tutorial ( http://wiki.ros.org/velodyne/Tutorial... ) to establish connection using command below,

   $ sudo ifconfig eth0 192.168.3.100

   $ sudo route add 192.168.XX.YY eth0

however, according to wireshark, connection wasn't established at all.

1. Now I can see (gladly) the pointcloud, I really want to extract X,Y, and Z coordinates with intensity from .pcap file. I found some great sources to start ( https://github.com/PointCloudLibrary/pcl ), but I am not sure whether I can pull this off by myself :(

Any advice would be superb!! Thank you :)