Quartic (biweight) kernel density of point counts per unit area,
sum_i c_i 3 / (pi h^2) (1 - d^2 / h^2)^2 for d < h.
Usage
PopulationDensitySurface(points, counts, grid, bandwidth)
Arguments
- points
Two-column matrix of point coordinates.
- counts
Population at each point.
- grid
Two-column matrix of evaluation locations.
- bandwidth
Kernel radius h.
Value
list(density, total).
References
Silverman, B. W. (1986). Density Estimation for Statistics and
Data Analysis. Chapman and Hall, Sec. 4.2.
Examples
PopulationDensitySurface(matrix(0, 1, 2), 10, matrix(0, 1, 2), 1)$density * pi
#> [1] 30
