Q. How can I convert output of LeGO-LOAM to 2D grid map for path planning?

[yyongjae]

My question is on the title.
I want to make a 2D(x,y) Grid map for path planning.
So I checked pointcloud through RVIZ and I think '/segmented_cloud_pure' topic is suitable for my task. (Is this right? It's from imageProjection.cpp)

Then, I wonder that if segmentedCloudPure(pcl:Pointcloud data) had over 10,000 points, what means the sequence of the points?