Subscribing and publishing to the same topic (/map) in a single python ros node

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My goal is to process a PointCloud2 and visualize it in RViz. I have rosbag data collected. This rosbag file includes /map, /tf, /ssl_slam/trajectory topics. The /map topic is in the form of sensor_msgs/PointCloud2 messages. In the single ros node I want to: 1) Read the incoming pointcloud2 messages (from /map topic) and perform point cloud processing, 2) publish back to the same /map topic. Essentially I am trying to modify data on a topic and republish it on the same topic (/map).

I looked at several pages explaining how to construct a publisher and subscriber in the same ros node, but I understand that if subscribe and publish to the same topic, you will get an endless loop because the callback function triggers itself by publishing. I also understand that I need to create a different topic for the outgoing data and map this outgoing data to the different topic (i.e. not the same /map topic), but I am clueless on how to go about doing this. I need to be able to visualize the pointcloud2 messages from the different topic (which I have not created yet) in RViz. This will be my 'processed' pointcloud. Please help. Here is what I have currently:

import pdb
import rospy
from roslib import message
import math
import numpy as np
import sensor_msgs.point_cloud2 as pc2
from sensor_msgs.msg import PointCloud2, PointField
from std_msgs.msg import Header
from ros_numpy.point_cloud2 import pointcloud2_to_array, array_to_pointcloud2, split_rgb_field, merge_rgb_fields


class PCLprocessor(object):
    def __init__(self):
        self.lastpcl_data = 0
        rospy.init_node('pclprocessor')

        self.pclpublisher = rospy.Publisher('/map', PointCloud2, latch=True, queue_size=1000)

        rospy.Subscriber('/map', PointCloud2, self.pcl_callback)
        rospy.spin()

def pcl_callback(self, pcl2data):
    self.pcl_data = pcl2data
    pdb.set_trace()
    self.pcl2_array = pointcloud2_to_array(self.pcl_data)
    self.pcl2_array = split_rgb_field(self.pcl2_array)
    print('pcl2 array shape BEFORE color separation: ', self.pcl2_array.shape)

    self.maskint1 = (self.pcl2_array['r'] <= 190)
    self.maskint2 = (self.pcl2_array['g'] <= 190)
    self.maskint3 = (self.pcl2_array['b'] >= 140)
    self.pcl2_array = self.pcl2_array[np.logical_not(
        np.logical_and(self.maskint1, self.maskint2, self.maskint3))]

    self.pcl2_array = merge_rgb_fields(self.pcl2_array)
    print('pcl2 array shape AFTER color separation: ', self.pcl2_array.shape)
    self.lastpcl_data = array_to_pointcloud2(self.pcl2_array)
    print('CHECKPOINT ****1')

def run(self):
    print("CHECKPOINT: def run(self)")
    r = rospy.Rate(10)
    while not rospy.is_shutdown():
        self.pclpublisher.publish(self.lastpcl_data)
        print("CHECKPOINT: after publishing self.lastpcldata")
        r.sleep(0.5)

if __name__ == '__main__':
    PCLprocessor()