Reproject point cloud and tree coordinate

[Lan Tran]

Hi,

I am analyzing point clouds acquired from drone lidar and handheld lidar. Drone lidar contains coordinate itself and I did reproject handheld lidar point cloud to same coordinate. However, when I check the location of trees for further comparison, they are not in same location even though 2 point clouds have same coordinate. Do you know any solution to solve this? Any help is appreciated! 

Best,

Lan Tran

[Alvin Qiu]

Hi Lan,

Thank you for sending a message on the LiDAR360 Forum.

In the latest LiDAR360 v7, you may try the Data Registration tool -> Point Pairs, to select a few pairs (at least 3) of common points in the overlapping areas of the two datasets to apply the transformation. 

If you are using LiDAR360 older than v7, you may try the following:

1. Use the pick multi-point tool to pick a few pairs of the common points in the overlapping areas of the two datasets, save the coordinates into two separate files

2. Use the Transformation Calculation tool to calculate a four-parameter transformation relationship

3. Apply a four-parameter transformation in the Transformation tool. 

Please choose one of the data that you believe to be more accurate as the reference data, and align another data that is less accurate to the reference data. Based on your description, I think the airborne data might be a bit more accurate? 

Please let me know if you have any questions.

Best,

Alvin Qiu

GVI Support Team