How to spllit laserscan data from lidar into sections and view them on rviz - ros

Question

I was trying to split the laser scan range data into subcategories and like to publish each category into different laser topics.
to specify more, the script should get one topic as an input - /scan and the script should publish three topics as follow = scan1, scan2, scan3
is there a way to split the laser scan and publish back and look them on rviz
I tried the following
def callback(laser):
current_time = rospy.Time.now()
regions["l_f_fork"] = laser.ranges[0:288]
regions["l_f_s"] = laser.ranges[289:576]
regions["stand"] = laser.ranges[576:864]
l.header.stamp = current_time
l.header.frame_id = 'laser'
l.angle_min = 0
l.angle_max = 1.57
l.angle_increment =0
l.time_increment = 0
l.range_min = 0.0
l.range_max = 100.0
l.ranges = regions["l_f_fork"]
l.intensities = [0]
left_fork.publish(l)
# l.ranges = regions["l_f_s"]
# left_side.publish(l)
# l.ranges = regions["stand"]
# left_side.publish(l)
rospy.loginfo("publishing new info")
I can see the different topics on rviz, but they are lies on the same line,

Answer 1

Tutorial
The following code splits the LaserScan data into three equal sections:
#! /usr/bin/env python3
"""
Program to split LaserScan into three parts.
"""
import rospy
from sensor_msgs.msg import LaserScan
class LaserScanSplit():
"""
Class for splitting LaserScan into three parts.
"""
def __init__(self):
self.update_rate = 50
self.freq = 1./self.update_rate
# Initialize variables
self.scan_data = []
# Subscribers
rospy.Subscriber("/scan", LaserScan, self.lidar_callback)
# Publishers
self.pub1 = rospy.Publisher('/scan1', LaserScan, queue_size=10)
self.pub2 = rospy.Publisher('/scan2', LaserScan, queue_size=10)
self.pub3 = rospy.Publisher('/scan3', LaserScan, queue_size=10)
# Timers
rospy.Timer(rospy.Duration(self.freq), self.laserscan_split_update)
def lidar_callback(self, msg):
"""
Callback function for the Scan topic
"""
self.scan_data = msg
def laserscan_split_update(self, event):
"""
Function to update the split scan topics
"""
scan1 = LaserScan()
scan2 = LaserScan()
scan3 = LaserScan()
scan1.header = self.scan_data.header
scan2.header = self.scan_data.header
scan3.header = self.scan_data.header
scan1.angle_min = self.scan_data.angle_min
scan2.angle_min = self.scan_data.angle_min
scan3.angle_min = self.scan_data.angle_min
scan1.angle_max = self.scan_data.angle_max
scan2.angle_max = self.scan_data.angle_max
scan3.angle_max = self.scan_data.angle_max
scan1.angle_increment = self.scan_data.angle_increment
scan2.angle_increment = self.scan_data.angle_increment
scan3.angle_increment = self.scan_data.angle_increment
scan1.time_increment = self.scan_data.time_increment
scan2.time_increment = self.scan_data.time_increment
scan3.time_increment = self.scan_data.time_increment
scan1.scan_time = self.scan_data.scan_time
scan2.scan_time = self.scan_data.scan_time
scan3.scan_time = self.scan_data.scan_time
scan1.range_min = self.scan_data.range_min
scan2.range_min = self.scan_data.range_min
scan3.range_min = self.scan_data.range_min
scan1.range_max = self.scan_data.range_max
scan2.range_max = self.scan_data.range_max
scan3.range_max = self.scan_data.range_max
# LiDAR Range
n = len(self.scan_data.ranges)
scan1.ranges = [float('inf')] * n
scan2.ranges = [float('inf')] * n
scan3.ranges = [float('inf')] * n
# Splitting Block [three equal parts]
scan1.ranges[0 : n//3] = self.scan_data.ranges[0 : n//3]
scan2.ranges[n//3 : 2*n//3] = self.scan_data.ranges[n//3 : 2*n//3]
scan3.ranges[2*n//3 : n] = self.scan_data.ranges[2*n//3 : n]
# Publish the LaserScan
self.pub1.publish(scan1)
self.pub2.publish(scan2)
self.pub3.publish(scan3)
def kill_node(self):
"""
Function to kill the ROS node
"""
rospy.signal_shutdown("Done")
if __name__ == '__main__':
rospy.init_node('laserscan_split_node')
LaserScanSplit()
rospy.spin()
The following are screenshots of the robot and obstacles in the environment in Gazebo and RViz:
References:
ROS1 Python Boilerplate
atreus