Global Mapper v25.0

Is updating Lidar Statistics after every manual reclassification really necessary?

I often remove non-permanent objects (such as stationary cars, people, etc) manually from the point cloud ground layer by using the path profile tool and systematically reclassifying the irrelevant points. This worked great in GM v. 22.0, but since upgrading to GMPro 23.1, the program takes several seconds to "update Lidar statistics", after every manual reclassification, even if I'm only changing a handful of points. This means the time needed for removal is increased significantly, to the point of this feature being unusable when working on a larger scale.

The time needed for this seems to increase in proportion with the size of the point cloud. I only have a limited knowledge of programming, but it shouldn't take such a long time to update a few numbers in the statistics, and the program really shouldn't need to process the entire cloud every time a point is reclassified.

Any thoughts on this?

Answers

  • bmg_mike
    bmg_mike Global Mapper Guru Moderator, Trusted User

    I took a look and found that the Lidar statistics were indeed being calculated immediately when a change was made rather than deferred until actually needed.

    For most point clouds the stats calculate so fast that it wouldn't really matter, but when you get a few hundred million points or more in a point cloud (or a lower end machine), you can see delays of a second or more. I now no longer see any noticeable delay on my machine.

    Tomorrow's v24.0.x daily build at https://www.bluemarblegeo.com/products/global-mapper-daily-builds.php will have this update.

    Thanks,

    Mike

    Global Mapper Guru

  • I have been having this issue also. It's on and off, seemingly randomly. That being said, it doesn't do it if all point classes are turned on within the point cloud. I'm using the same methodology as ingvar204 above. Global Mapper Pro v25.1 b021424. I'm operating on a LAZ point cloud with ~204M points. This is a fairly high-powered computer, but still can take ~1 min to calculate lidar stats for changing even just a single point's class. CPU, RAM, and GPU specs listed below.

    NVIDIA GeForce RTX 4080 graphics card.


    -David

  • bmg_mike
    bmg_mike Global Mapper Guru Moderator, Trusted User

    David,

    We have made some significant improvements to Lidar statistics calculations for the upcoming v26.0 release, with potentially even more coming (if we have time). So hopefully this problem will mostly go away.

    Thanks,

    Mike

    Global Mapper Guru