Using LiDAR in SURE

Related topics:

LiDAR Integration in SURE

Project Setup

Introduction


LiDAR data can be provided as part of the normal SURE Project definition wizard (GUI and CLI), as well as in custom workflows using either the 2.5D Tool or the Command Line Modules.

The LiDAR point clouds are provided by specifying the parent directory of the LAS files. Alternatively, the user can specify a list text file with each entry pointing to the individual LiDAR LAS files.

The LiDAR Trajectory file is provided as the path to the respective file.


SURE Project Definition 

GUI

CLI


CLI
SURE.exe -basepath ... -ori ... -img ... -scenario ... -lidar <path_to_lidar_las_point_clouds> -lidar_trajectory <path_to_trajectory_file> ...

See additional information at Project Setup article. 

SURE Custom Workflows

2.5D Tool


Command Line Modules


ModuleDsm.exe
ModuleDsm.exe --cloud <path_to_dense_image_matching_clouds> --lidar <path_to_lidar_las_point_clouds> ...


ModuleDsm.exe --help

Command Line Parameters:
  -h [ --help ]                       Print help screen
  --log arg (=log.txt)                Path to logfile.
  --output arg (=.)                   Path to output folder.
  --controlfile arg (=controlDsm.txt) Path to ControlDsm.txt control file.
  --area arg (=controlArea.txt)       Path to controlArea.txt control file.
  --gsd arg                           Value for ground sampling distance.
  --cloud arg (=cloudlist.txt)        Path to 3D Points (.las/.laz) or mesh
                                      (.osgb) list, file or folder.
  --lidar arg                         Path to LiDAR points (.las/.laz) list,
                                      file or folder.
  --no_lidar                          Disable usage of LiDAR data (modifies
                                      controlDsm.txt)
  --waterbody arg                     Path shape file for waterbody surface.
Module3DMesh.exe
Module3DMesh.exe --cloud <path_to_cloudlist_filtered.txt> --cam <path_to_cloudlist_filtered_meta.txt> --lidar <path_to_lidar_las_point_clouds> --lidar_trajectory <path_to_lidar_trajectory_file>


Module3DMesh.exe --help

Command Line Parameters:
  -h [ --help ]                         Print help screen
  --log arg (=log.txt)                  Path to logfile.
  --output arg (=.)                     Path to output folder.
  --controlfile arg (=control3DMesh.txt)
                                        Path to control3DMesh.txt control file.
  --area arg (=controlArea.txt)         Path to controlArea.txt control file.
  --cloud arg (=cloudlist_filtered.txt) Path to (filtered)  3D Points list,
                                        file or folder.
  --lidar arg                           Path to LiDAR points (.las/.laz) list,
                                        file or folder.
  --no_lidar                            Disable usage of LiDAR data (modifies
                                        control3DMesh.txt)
  --lidar_trajectory arg                Path to LiDAR trajectory file.
  --ori arg (=orilist.txt)              Path to .ori list, file or folder.
  --cam arg (=cloudlist_filtered_meta.txt)
                                        Path to (filtered) 3D Points
                                        metainformation lists.
  --waterbody arg                       Path shape file for waterbody surface
                                        (only used for LiDAR clouds, DIM clouds
                                        are handled in Cloud Filter.


Processing with LiDAR

If LiDAR data is provided as input during the project generation in SURE (versions post 3.0), then LiDAR will be automatically integrated in the workflow by default. Thus the user does not have to change any other setting regarding the processing of the new input. It is possible to turn off the usage of LiDAR individually for each of the processing steps (DSM or 3D Mesh), by disabling the respective parameters in the GUI or by using the --no_lidar Command Line flag.

Performance optimization

It is recommended that the LiDAR point clouds are tiled in a scheme similar to the one employed in the SURE project. During the DSM step and the 3D Mesh step, the data is processed per tile. As such, SURE will load in memory all the necessary files that contain data which overlap with the currently processed tile. If the LiDAR data usage is enabled, this will include the DIM data, as well as the LiDAR data. Therefore the most optimal configuration - with minimum impact on processing time - will have the LiDAR point clouds tiled exactly as the DIM data. 

SURE Tiling Scheme

The SURE Project tiling scheme can be controlled by using the rectangular way of defining the Project Area (Xmin - Xmax / Ymin - Ymax), together with the tile size setting. This can be used as well in conjunction with the Area Shape functionality. See more details in the Project Area article. 

The principle is illustrated bellow:

Sub-optimal 

Optimal

In the example below it can be seen that the LiDAR Point Cloud Strips are much larger than the Area of Interest and thus SURE would have to load for every DIM tile the entire LiDAR strip.

Source: Leica - Bordeaux dataset

If the user would clip the LiDAR strips in a way that it suits the size of the DIM tile, then the processing of the DSM / Mesh will run faster (also less disk space will be used if Distributed processing is enabled). In the example below the LiDAR strips were clipped and exported as 8 individual smaller parts as the size of the DSM tile. Then a list containing the paths to these clouds was created and used as input in SURE.

Key Features