Global Mapper v24.0

Avoiding power poles, power lines, and building edges when classifying points or extracting trees

I have a point cloud that came classified but the classifications were not that great and included a lot of points in wrong classes.  For example the high vegetation classification includes a lot of power lines, power poles, and building perimeters.  So I decided to clear the classifications and reclassify using GMv21.  However I get similar results to the previous classifications, with the high veg including a lot of power line/poles.  

This means when i extract trees i am getting long lines of "tree points" where it is actually a power line and no trees exist (confirmed via google street view).  The point cloud is not dense enough to properly do a power line auto classification, or so the dialog box in GM tells me, it needs 20 points/m^2 whereas i have 13.  So I can't classify power features and separate them out that way.

So looking for suggestions of how to get tree points out without a bunch of power poles and building edges showing up as trees?  I thought of using the intensity value to differentiate between a power pole and a tree but not sure how that would happen or that is a good approach.

Answers

  • Here is a screenshot to show the issue.  The red circled point cluster is a tree that did not get identified as a tree though it meets the extraction criteria (over 2m tall, etc.) the blue circled points are all power lines that get interpreted as trees, and there's a power pole in there too, but I don't see why a power line that is just a handful of points can get considered a tree while a dense cluster (red circle) is not considered a tree.
Sign In or Register to comment.