title: Intel L515 .Bag file for making a point cloud?
body: <p>Using Linux Focal Fossa LTS 20.04 , ROS for reading the .bag files generated by the SDK 2.0 of Intel RealSense L515 Lidar.
  Successfully can read messages by installing ROS as stated above, version of ROS= Noetic NinJemys.</p>
  <pre><code>Command used to read .bag file was :
  rostopic echo [topic_Name] | grep -E topic1.yaml
  
  Able to get output of file as mentioned below:
  
  (base) tdi@ubuntu:~/Desktop$ rosbag play tdi.bag
  [ INFO] [1644590487.119679521]: Opening tdi.bag
  
  Waiting 0.2 seconds after advertising topics... done.
  
  Hit space to toggle paused, or 's' to step.
   [RUNNING]  Bag Time:      9.301230   Duration: 9.301230 / 9.310886               90487.42 
  Done.
  (base) tdi@ubuntu:~/Desktop$ time rosbag info tdi.bag
  path:         tdi.bag
  version:      2.0
  duration:     9.3s
  start:        Dec 31 1969 16:00:00.00 (0.00)
  end:          Dec 31 1969 16:00:09.31 (9.31)
  size:         151.4 MB
  messages:     14521
  compression:  lz4 [281/281 chunks; 60.94%]
  uncompressed: 247.8 MB @ 26.6 MB/s
  compressed:   151.0 MB @ 16.2 MB/s (60.94%)
  types:        diagnostic_msgs/KeyValue    [cf57fdc6617a881a88c16e768132149c]
                geometry_msgs/Transform     [ac9eff44abf714214112b05d54a3cf9b]
                realsense_msgs/ImuIntrinsic [aebdc2f8f9726f1c3ca823ab56e47429]
                realsense_msgs/StreamInfo   [311d7e24eac31bb87271d041bf70ff7d]
                sensor_msgs/CameraInfo      [c9a58c1b0b154e0e6da7578cb991d214]
                sensor_msgs/Image           [060021388200f6f0f447d0fcd9c64743]
                sensor_msgs/Imu             [6a62c6daae103f4ff57a132d6f95cec2]
                std_msgs/Float32            [73fcbf46b49191e672908e50842a83d4]
                std_msgs/Float32MultiArray  [6a40e0ffa6a17a503ac3f8616991b1f6]
                std_msgs/String             [992ce8a1687cec8c8bd883ec73ca41d1]
                std_msgs/UInt32             [304a39449588c7f8ce2df6e8001c5fce]
  topics:       /device_0/info                                                       12 msgs    : diagnostic_msgs/KeyValue   
                /device_0/sensor_0/Depth_0/image/data                               280 msgs    : sensor_msgs/Image          
                /device_0/sensor_0/Depth_0/image/metadata                          1400 msgs    : diagnostic_msgs/KeyValue   
                /device_0/sensor_0/Depth_0/info                                       1 msg     : realsense_msgs/StreamInfo  
                /device_0/sensor_0/Depth_0/info/camera_info                           1 msg     : sensor_msgs/CameraInfo     
                /device_0/sensor_0/Depth_0/tf/0                                       1 msg     : geometry_msgs/Transform    
                /device_0/sensor_0/Infrared_0/image/data                            280 msgs    : sensor_msgs/Image          
                /device_0/sensor_0/Infrared_0/image/metadata                       1400 msgs    : diagnostic_msgs/KeyValue   
                /device_0/sensor_0/Infrared_0/info                                    1 msg     : realsense_msgs/StreamInfo  
                /device_0/sensor_0/Infrared_0/info/camera_info                        1 msg     : sensor_msgs/CameraInfo     
                /device_0/sensor_0/Infrared_0/tf/0                                    1 msg     : geometry_msgs/Transform    
                /device_0/sensor_0/info                                               2 msgs    : diagnostic_msgs/KeyValue   
                /device_0/sensor_0/l500_data                                          1 msg     : std_msgs/Float32MultiArray 
                /device_0/sensor_0/option/Alternate_IR/description                    1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Alternate_IR/value                          1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Apd_Temperature/description                 1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Apd_Temperature/value                       1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Confidence_Threshold/description            1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Confidence_Threshold/value                  1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Depth_Offset/description                    1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Depth_Offset/value                          1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Depth_Units/description                     1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Depth_Units/value                           1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Digital_Gain/description                    1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Digital_Gain/value                          1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Enable_IR_Reflectivity/description          1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Enable_IR_Reflectivity/value                1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Enable_Max_Usable_Range/description         1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Enable_Max_Usable_Range/value               1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Error_Polling_Enabled/description           1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Error_Polling_Enabled/value                 1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Frames_Queue_Size/description               1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Frames_Queue_Size/value                     1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Freefall_Detection_Enabled/description      1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Freefall_Detection_Enabled/value            1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Global_Time_Enabled/description             1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Global_Time_Enabled/value                   1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Host_Performance/description                1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Host_Performance/value                      1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Humidity_Temperature/description            1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Humidity_Temperature/value                  1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Inter_Cam_Sync_Mode/description             1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Inter_Cam_Sync_Mode/value                   1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Invalidation_Bypass/description             1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Invalidation_Bypass/value                   1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/LDD_temperature/description                 1 msg     : std_msgs/String            
                /device_0/sensor_0/option/LDD_temperature/value                       1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Laser_Power/description                     1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Laser_Power/value                           1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Ma_Temperature/description                  1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Ma_Temperature/value                        1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Mc_Temperature/description                  1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Mc_Temperature/value                        1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Min_Distance/description                    1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Min_Distance/value                          1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Noise_Estimation/description                1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Noise_Estimation/value                      1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Noise_Filtering/description                 1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Noise_Filtering/value                       1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Post_Processing_Sharpening/description      1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Post_Processing_Sharpening/value            1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Pre_Processing_Sharpening/description       1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Pre_Processing_Sharpening/value             1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Receiver_Gain/description                   1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Receiver_Gain/value                         1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Sensor_Mode/description                     1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Sensor_Mode/value                           1 msg     : std_msgs/Float32           
                /device_0/sensor_0/option/Visual_Preset/description                   1 msg     : std_msgs/String            
                /device_0/sensor_0/option/Visual_Preset/value                         1 msg     : std_msgs/Float32           
                /device_0/sensor_0/post_processing                                    1 msg     : std_msgs/String            
                /device_0/sensor_1/info                                               2 msgs    : diagnostic_msgs/KeyValue   
                /device_0/sensor_1/option/Auto_Exposure_Priority/description          1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Auto_Exposure_Priority/value                1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/Backlight_Compensation/description          1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Backlight_Compensation/value                1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/Brightness/description                      1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Brightness/value                            1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/Contrast/description                        1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Contrast/value                              1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/Enable_Auto_Exposure/description            1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Enable_Auto_Exposure/value                  1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/Enable_Auto_White_Balance/description       1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Enable_Auto_White_Balance/value             1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/Exposure/description                        1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Exposure/value                              1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/Frames_Queue_Size/description               1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Frames_Queue_Size/value                     1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/Gain/description                            1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Gain/value                                  1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/Global_Time_Enabled/description             1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Global_Time_Enabled/value                   1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/Host_Performance/description                1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Host_Performance/value                      1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/Hue/description                             1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Hue/value                                   1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/Power_Line_Frequency/description            1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Power_Line_Frequency/value                  1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/Saturation/description                      1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Saturation/value                            1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/Sharpness/description                       1 msg     : std_msgs/String            
                /device_0/sensor_1/option/Sharpness/value                             1 msg     : std_msgs/Float32           
                /device_0/sensor_1/option/White_Balance/description                   1 msg     : std_msgs/String            
                /device_0/sensor_1/option/White_Balance/value                         1 msg     : std_msgs/Float32           
                /device_0/sensor_1/post_processing                                    1 msg     : std_msgs/String            
                /device_0/sensor_2/Accel_0/imu/data                                 925 msgs    : sensor_msgs/Imu            
                /device_0/sensor_2/Accel_0/imu/metadata                            4625 msgs    : diagnostic_msgs/KeyValue   
                /device_0/sensor_2/Accel_0/imu_intrinsic                              1 msg     : realsense_msgs/ImuIntrinsic
                /device_0/sensor_2/Accel_0/info                                       1 msg     : realsense_msgs/StreamInfo  
                /device_0/sensor_2/Accel_0/tf/0                                       1 msg     : geometry_msgs/Transform    
                /device_0/sensor_2/Gyro_0/imu/data                                  914 msgs    : sensor_msgs/Imu            
                /device_0/sensor_2/Gyro_0/imu/metadata                             4570 msgs    : diagnostic_msgs/KeyValue   
                /device_0/sensor_2/Gyro_0/imu_intrinsic                               1 msg     : realsense_msgs/ImuIntrinsic
                /device_0/sensor_2/Gyro_0/info                                        1 msg     : realsense_msgs/StreamInfo  
                /device_0/sensor_2/Gyro_0/tf/0                                        1 msg     : geometry_msgs/Transform    
                /device_0/sensor_2/info                                               1 msg     : diagnostic_msgs/KeyValue   
                /device_0/sensor_2/option/Enable_Motion_Correction/description        1 msg     : std_msgs/String            
                /device_0/sensor_2/option/Enable_Motion_Correction/value              1 msg     : std_msgs/Float32           
                /device_0/sensor_2/option/Frames_Queue_Size/description               1 msg     : std_msgs/String            
                /device_0/sensor_2/option/Frames_Queue_Size/value                     1 msg     : std_msgs/Float32           
                /device_0/sensor_2/option/Global_Time_Enabled/description             1 msg     : std_msgs/String            
                /device_0/sensor_2/option/Global_Time_Enabled/value                   1 msg     : std_msgs/Float32           
                /file_version                                                         1 msg     : std_msgs/UInt32
  </code></pre>
  <p>MAIN PROBLEM:
  HOW CAN WE EXTRACT THE POINT CLOUD DATA ( x,y,z ) values for all points in point cloud.</p>
  <p>I am new to ROS, so please ignore if something is worth mentioning that i may have overlooked.</p>