discpartarea
Area of Part of Disc
Compute area of intersection between a disc and a window
Usage
discpartarea(X, r, W=as.owin(X))Arguments
- X
Point pattern (object of class
"ppp") specifying the centres of the discs. Alternatively,Xmay be in any format acceptable toas.ppp.- r
Matrix, vector or numeric value specifying the radii of the discs.
- W
Window (object of class
"owin") with which the discs should be intersected.
Details
This algorithm computes the exact area of the intersection between
a window W and a disc (or each of several discs).
The centres of the discs are specified by the point pattern
X, and their radii are specified by r.
If r is a single numeric value, then the algorithm computes the
area of intersection between W and the disc of radius r centred
at each point of X, and returns a one-column matrix
containing one entry for each point of X.
If r is a vector of length m, then the algorithm
returns an n * m matrix in which the entry on row i,
column j is the area of the
intersection between W and the disc centred at X[i]
with radius r[j].
If r is a matrix, it should have one row for each point in
X. The algorithm
returns a matrix in which the entry on row i,
column j is the area of the
intersection between W and the disc centred at X[i]
with radius r[i,j].
Areas are computed by analytic geometry.
Value
Numeric matrix, with one row for each point of X.
See Also
Examples
# NOT RUN {
data(letterR)
X <- runifpoint(3, letterR)
discpartarea(X, 0.2)
# }