I am trying to use libLAS to read an LAS file and perform a coordinate 
transformation.  Points in the file are stored in UTM coordinates.  I would 
like to transform them into geocentric coordinates.  As best I can tell, the 
version of libLAS I am using (1.6.1) does not support conversion to geocentric 
coordinates, so my backup plan is to convert to WGS84 geodetic coordinates 
(lat., long. , height above ellipsoid), and then perform the 
geodetic-to-geocentric conversion myself.

The problem is that when I set up a ReprojectionTransform to convert the points 
from UTM to geodetic coordinates, the resulting latitude and longitude of each 
point has nonzero digits only to the hundredth of a degree, even though the UTM 
coordinates of my input points have data to the millimeter.  For example, here 
are the results of two such conversions:

UTM (Easting, Northing) ---> Geodetic (Longitude, Latitude)
831805.86 4296378.26 ---> -77.18 38.75
831806.31 4296377.64 ---> -77.18 38.75

Even though the points have different UTM easting and northing coordinates, 
they are transformed to the same latitude and longitude.  Is this limited 
precision inherent in the way libLAS does its coordinate conversions, or am I 
setting up the transform object(s) incorrectly?

I apologize if this is a duplicate post.  I tried to send this yesterday before 
joining the mailing list.

Thanks for your time,
 
Dave Edwards
Software Engineer
Integrity Applications Inc.

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