[R-sig-Geo] Irregularly spaced 3D point clustering / segmentation

[Michael Sumner]

Hello,

 I have no suggestions for helping yet, but I'd rather like to play with 
some LIDAR forest data. Is there some publicly available that you can 
point me to?  I have messed around with rgl for interactive 3-D view of 
similar things, and would like to explore more.

Cheers, Mike.

Andrew Niccolai wrote:
> Greetings fellow R users,
>
> I would really enjoy (and eagerly anticipate) any discussions on ideas for
> handling a LIDAR (laser) data set of a New England forest.  The LIDAR
> dataset is essentially xyz coordinates that form an irregularly spaced 3D
> data cloud of points.  I have brought the data in as SpatialPointsDataFrame,
> SpatialPixelsDataFrame, SpatialGridDataFrame, marked Point Pattern Process
> objects, matrices etc.  I can view the interpolated surface with ?interp in
> library(akima) as well as 3D points and surfaces in library(rgl).
>
> So, importing the LIDAR data and viewing it or exporting it so that ImageJ
> can handle it is not the issue.  
>
> The LIDAR data set essentially produces a set of "mounds" from the elevation
> data recorded in the z variable.  Each "mound" represents a tree in the
> forest.  I am hoping to get some ideas on ways to cluster this data set so
> that I can isolate each mound for further analysis and segmentation.  One
> possibility that I have looked into with Matlab software is
> "marker-controlled watershed segmentation".  This essentially inverts the
> interpolated surface and "fills" the inverted image with "water" starting at
> the local minimas until the water starts to spill over into the next
> watershed at which point it builds a "dam" between local valleys.  This is a
> function in Matlab and I haven't been able to see the code to bring it to R.
>
> Any ideas on this method or suggestions for better methods to isolate
> "mounds" in 3D space?  Template matching, perhaps??
>
> Thanks in advance and thanks to all the innovative producers and users of
> the R domain!!  
> Andrew
>
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo at stat.math.ethz.ch
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>
>
>