Importing point cloud xyz
scr
Global Mapper UserTrusted User
Hello
I searched the forum about handling a big point cloud (in my case 50'000'000) but couldn't find a satisfying answer.
I have an ASCII file with xyz. The data is representing LIDAR data. It is actually a grid 0.5/0.5m with elevation.
I need to crop that data to different polygon area which I created in Global Mapper.
But it is really slow.
Any ideas?
Thanks Rainer
I searched the forum about handling a big point cloud (in my case 50'000'000) but couldn't find a satisfying answer.
I have an ASCII file with xyz. The data is representing LIDAR data. It is actually a grid 0.5/0.5m with elevation.
I need to crop that data to different polygon area which I created in Global Mapper.
But it is really slow.
Any ideas?
Thanks Rainer
Comments
-
Rainer,
Which part is slow? If you load it in as a Lidar point cloud, select the polygon, then export out to a new XYZ file and choose to crop to the polygon the slow part might be the 50,000,000 point-in-polygon checks, especially if the polygon is complex. Does it have a lot of vertices?
That said, I have plans to dramatically speed up operations that require large numbers of point-in-polygon tests, perhaps before the final v15 release, which could help if that is the slowdown.
Thanks,
Mike
Global Mapper Guru
geohelp@bluemarblegeo.com
Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation -
Hi Mike
I didn't load the data as Lidar point cloud. I opened the points directly as point data. The polygon itself was a test polygon and therefore very small.
I guess I can do now what I want to do.
Just to tell you: When I loaded this huge point cloud as points the program slowed down extremly, although the processor time sometimes was idle. For example i couldn't use die export menu because the export submenu didn't show up.
But anyway, thanks Rainer -
Rainer,
Loading that many as normal points would take a huge amount of memory, which probably caused you to swap to disk and everything to get slow. If you load as a point cloud the memory would only be a few hundred MB and it should go quite fast.
Thanks,
Mike
Global Mapper Guru
geohelp@bluemarblegeo.com
Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation
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