tess {spatstat} | R Documentation |
Creates an object of class "tess"
representing a tessellation
of a spatial region.
tess(..., xgrid = NULL, ygrid = NULL, tiles = NULL, image = NULL)
... |
Ignored. |
xgrid,ygrid |
Cartesian coordinates of vertical and horizontal lines determining a grid of rectangles. Incompatible with other arguments. |
tiles |
List of tiles in the tessellation.
A list, each of whose elements is a window
(object of class "owin" ). Incompatible with other arguments.
|
image |
Pixel image which specifies the tessellation. Incompatible with other arguments. |
A tessellation is a collection of disjoint spatial regions
(called tiles) that fit together to form a larger spatial
region. This command creates an object of class "tess"
that
represents a tessellation.
Three types of tessellation are supported:
x
and
y
axes. They may or may not have equal size and shape.
The arguments xgrid
and ygrid
determine
the positions of the vertical and horizontal grid lines,
respectively.
tiles
is a list of these tiles,
which are objects of class "owin"
.
image
is a pixel image (object of class
"im"
) with factor values. Each level of the factor
represents a different tile of the tessellation. The pixels that
have a particular value of the factor constitute a tile.
There are methods for print
, plot
, [
and [<-
for tessellations. Use tiles
to extract the list of
tiles in a tessellation.
Tessellations can be used to classify the points of
a point pattern, in split.ppp
, cut.ppp
and
by.ppp
.
An object of class "tess"
representing the tessellation.
Adrian Baddeley adrian@maths.uwa.edu.au http://www.maths.uwa.edu.au/~adrian/ and Rolf Turner r.turner@auckland.ac.nz
plot.tess
,
[.tess
,
tiles
,
split.ppp
,
cut.ppp
,
by.ppp
.
A <- tess(xgrid=0:4,ygrid=0:4) A B <- A[c(1, 2, 5, 7, 9)] B v <- as.im(function(x,y){factor(round(5 * (x^2 + y^2)))}, W=owin()) levels(v) <- letters[seq(length(levels(v)))] E <- tess(image=v) E