LiDAR Filter Settings and Flags

Is it possible to filter the LiDAR points that are displayed/processed using any flags that are set? I noticed that any points flagged as withheld are treated as deleted features but I'd like more control over this. Ex I'd like to be able to toggle on/off any points flagged as overlap. I see that the flags can be edited for a point but I'm not seeing anywhere to control the display of the flags. I would think this option would fit under the lidar filter settings window.

Thanks

Best Answers

  • bmg_bobbmg_bob Global Mapper Programmer Posts: 1,944
    Answer ✓
    Hello,

    Now I understand what you are looking for.  I have added feature request 19162 to our task list so we can evaluate it for inclusion in a future version of Global Mapper.  We will post a message on this thread when the status of the request changes.

    Thank you,
    Bob
  • bmg_mikebmg_mike Global Mapper Guru Posts: 184
    Answer ✓
    While there's not currently a way to turn off points for draw based on flags like withheld, synthetic, etc., you can easily select only those points that match that filter, then move those to a new layer. To do this, select all of the Lidar points, then right-click and select the Advanced Selection option to Filter Selected Lidar Points. Then choose the 'Keep Withheld Values of' option for either Yes or No. Once you have the appropriate group selected, then use the Edit menu to cut (or copy) them to the clipboard, then paste in a new layer. You can then turn off the original layer to only see the Withheld points.

    Thanks,

    Mike
    Global Mapper Guru
    geohelp@bluemarblegeo.com
    http://www.bluemarblegeo.com/
  • bmg_mikebmg_mike Global Mapper Guru Posts: 184
    Answer ✓
    There is a button on the Control Center to select all features in a selected layer, so you should be able to very quickly select all Lidar points in one or more layers.

    If you aren't on the latest daily build from http://data.bluemarblegeo.com/downloads/global-mapper/dailybuilds/ I'd suggest getting that as there have been many speed improvements.

Answers

  • bmg_bobbmg_bob Global Mapper Programmer Posts: 1,944
    Hello,

    The LiDAR toolbar has a function that allows you to filter the display by classification.  If you don't have the LiDAR toolbar, then filtering has to be done when importing or exporting the data.

    Cheers,
    Bob
  • JSOJSO Posts: 14
    edited September 2016
    Hi Bob,

    I'm looking to filter based on the classification bit fields that may be set and not classification alone. The LiDAR toolbar allows filtering on classification alone and does not take in to account any of the classification flags as far as I can tell.

    To be clear in my example, there is not an overlap class in my data. Instead points of any classification may have the overlap classification bit field set. I would like to toggle these points on/off. 
  • JSOJSO Posts: 14
    Great, thanks.
  • bmg_mikebmg_mike Global Mapper Guru Posts: 184Trusted User
    I have completed adding new Lidar draw and filter modes so you can color by the withheld, overlap, and key point flags. The Lidar import filter dialog also has a checkbox allowing you to control whether or not points marked as withheld are marked as deleted or not on import.

    The daily build at http://data.bluemarblegeo.com/downloads/global-mapper/dailybuilds/ will be updated tomorrow morning with these changes.

    Thanks,

    Mike
    Global Mapper Guru
    geohelp@bluemarblegeo.com
    http://www.bluemarblegeo.com/
  • JSOJSO Posts: 14
    Hi Mike, the color filter works well but I find that since the non withheld are still displayed as blue, it can be hard to see the red withheld points in cases where there is a small number of withheld points. Is there a way to display only the withheld points, overlap points, synthetic etc? In the lidar filter settings would be ideal, similiar to how return types can be enabled.
  • JSOJSO Posts: 14
    Hi Mike, thanks for the workaround, I didn't know it was possible to select from the flags from that. I'd still like to see a proper filtering operation added someday. This works but selecting all points in a typical LiDAR tile with 10's of millions of points is slow. 
  • JSOJSO Posts: 14
    bmg_mike said:
    There is a button on the Control Center to select all features in a selected layer, so you should be able to very quickly select all Lidar points in one or more layers.

    If you aren't on the latest daily build from http://data.bluemarblegeo.com/downloads/global-mapper/dailybuilds/ I'd suggest getting that as there have been many speed improvements.
    I know how to select all features but on a typical LiDAR tile the process is noticeably slow, GM appears to hang while the selection is running. I'm still on v19.1. I'll download the latest and give it a shot.
  • bmg_mikebmg_mike Global Mapper Guru Posts: 184Trusted User
    If you have a very large number of Lidar points selected and are zoomed out it can take a while to draw all of the selection boxes. The selection itself should be quite fast. 
  • JSOJSO Posts: 14
    Right, I forgot about that trick. It is the draw speed that is slow.
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