The Farthest Point Sampling Filter adds points from the input to the output
PointView one at a time by selecting the point from the input cloud that is
farthest from any point currently in the output.
filters.sample produces a similar result, but while
filters.sample allows us to target a desired separation of points via
radius parameter at the expense of knowing the number of points in
filters.farthestpointsampling allows us to specify exactly
the number of output points at the expense of knowing beforehand the
spacing between points.
Desired number of output samples. [Default: 1000]