  Using a coupling argument, we establish a general weak law of large numbers
for functionals of binomial point processes in d-dimensional space, with a
limit that depends explicitly on the (possibly non-uniform) density of the
point process. The general result is applied to the minimal spanning tree, the
k-nearest neighbors graph, the Voronoi graph, and the sphere of influence
graph. Functionals of interest include total edge length with arbitrary
weighting, number of vertices of specifed degree, and number of components. We
also obtain weak laws for functionals of marked point processes, including
statistics of Boolean models.
