test for in-tile for Dirichlet tile, using R

So I can take points and use the R libraries deldir or spatstat::dirichlet to find the dirichlet tesselation of those points.

Now I have a point not in the set, and I want to know the indices of the points forming the dirichlet tile which my not-in-set-point is interior to. I can get there by knowing the tile label (or index).

Are there any libraries or methods to do this? I'm thinking spatstat, but not finding something there yet.

Solution

The function cut.ppp() can take a point pattern and find which tesselation tile each point in the pattern belongs to. Below is the code for a simple example of a point pattern that only contains a single point (0.5, 0.5).

library(spatstat)
dd <- dirichlet(cells)
plot.tess(dd, do.labels = TRUE)
xx <- ppp(.5, .5, window = Window(dd))
plot(xx, add = TRUE, col = "red", cex = 2, pch = 20)

yy <- cut(xx, dd)
yy
#> Marked planar point pattern: 1 point
#> Multitype, with levels = 
#>    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 
#> 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
#> window: rectangle = [0, 1] x [0, 1] units
marks(yy)
#> [1] 18
#> 42 Levels: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 ... 42

^{Created on 2018-12-03 by the reprex package (v0.2.1)}