[R-sig-Geo] Methods for working with LIDAR data

[Waichler, Scott R]

I have a text file with x, y, z data from a LIDAR survey.  Can someone suggest a method to use to derive a Spatial Pixels or Spatial Grid object from these?  The spacing is not exactly regular of course.  The data are dense over all of the domain except for some blank areas, which I would like to designate as NA.  

I am open to using most packages and functions, but don't want to use GRASS.

Scott

Scott Waichler
Pacific Northwest National Laboratory
scott.waichler at pnl.gov