# intersect.tess

##### Intersection of Two Tessellations

Yields the intersection of two tessellations, or the intersection of a tessellation with a window.

##### Usage

`intersect.tess(X, Y, …, keepmarks=FALSE)`

##### Arguments

- X,Y
Two tessellations (objects of class

`"tess"`

), or windows (objects of class`"tess"`

), or other data that can be converted to tessellations by`as.tess`

.- …
Optional arguments passed to

`as.mask`

to control the discretisation, if required.- keepmarks
Logical value. If

`TRUE`

, the marks attached to the tiles of`X`

and`Y`

will be retained as marks of the intersection tiles.

##### Details

A tessellation is a collection of disjoint spatial regions
(called *tiles*) that fit together to form a larger spatial
region. See `tess`

.

If `X`

and `Y`

are not tessellations, they are first
converted into tessellations by `as.tess`

.

The function `intersect.tess`

then computes the intersection between
the two tessellations. This is another tessellation, each of whose
tiles is the intersection of a tile from `X`

and a tile from `Y`

.

One possible use of this function is to slice a window `W`

into
subwindows determined by a tessellation. See the Examples.

##### Value

A tessellation (object of class `"tess"`

).

##### See Also

##### Examples

```
# NOT RUN {
opa <- par(mfrow=c(1,3))
# polygon
data(letterR)
plot(letterR)
# tessellation of rectangles
X <- tess(xgrid=seq(2, 4, length=10), ygrid=seq(0, 3.5, length=8))
plot(X)
plot(intersect.tess(X, letterR))
A <- runifpoint(10)
B <- runifpoint(10)
plot(DA <- dirichlet(A))
plot(DB <- dirichlet(B))
plot(intersect.tess(DA, DB))
par(opa)
marks(DA) <- 1:10
marks(DB) <- 1:10
plot(Z <- intersect.tess(DA,DB, keepmarks=TRUE))
mZ <- marks(Z)
tZ <- tiles(Z)
for(i in which(mZ[,1] == 3)) plot(tZ[[i]], add=TRUE, col="pink")
# }
```

*Documentation reproduced from package spatstat, version 1.57-1, License: GPL (>= 2)*