[R-sig-Geo] decimate points from a Lidar file

[Michael Denslow]

Dear R-sig-geo,

I am posting the following question for one of my professors. I would
appreciate it if you could help me point him in the right direction.

He is looking for a function which could take a lidar point shapefile
and decimate (remove) a selected number of points
from the file. Below is what he asked me. The file of the merged LIDAR
tiles contains roughly 350,000,000 points.

"I am looking for some software to take a shapefile of lidar elevation
points and remove a selected number of points. The shapefile
(with fewer points) would then be used to generate a DEM. A
calculation of the appropriate resolution for a DEM can be made based
on a relationship between the
number of points and extent of the study area. The goal is to create
DEMs at a series of resolutions with the appropriate points to area
relationship. So a
software program with which you could remove a selected number of
lidar points would be helpful."

I imagine that one of the packages that deals with point data (e.g.
sp, spatstat) can do this kind of thing but I am not sure how to get
him started. Can anyone point me to a specify function or make a
suggestion.

Thanks in advance,
Michael

-- 
Michael Denslow

Graduate Student
I.W. Carpenter Jr. Herbarium [BOON]
Department of Biology
Appalachian State University
Boone, North Carolina U.S.A.

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Communications Manager
Southeast Regional Network of Expertise and Collections
sernec.org