Description Usage Arguments Details Value Author(s) See Also Examples
Draws a Halton Iterative Partition (HIP) sample from a
SpatialPoints*
object.
1 |
x |
A |
n |
Sample size. The number locations to draw from the set of points
contained in |
J |
A 2X1 vector of base powers. |
plot.lattice |
Boolean. If TRUE, plots the sample drawn with corresponding halton lattice. |
A brief description of Halton Iterative Partition (HIP) sampling for points:
Given a set of Halton Iterative Partition parameters
x
(SpatialPoints* object) and n
(sample size),
a lattice of Halton boxes is constructed iteratively over the bounding box
of x
.
This results in enough Halton boxes on the bounding box to uniquely
cover the point resource. That is, one and only one point per
box.
The Halton index (the inverse of the Halton sequence) of all boxes
is computed and assigned to points that lie
in each box. Finally, a random number between 0 and the largest Halton index is
drawn, and the next n
points associated with the
next n
Halton boxes are taken as
the sample, wrapping to the beginning if necessary.
A SpatialPoints
objects containing locations in the
HIP sample, in HIP order.
Additional attributes of the output object, beyond those which
make it a SpatialPoints
, are:
frame
: Name of the input sampling frame.
frame.type
: Type of resource in sampling frame. (i.e., "point").
sample.type
: Type of sample drawn. (i.e., "HIP").
J
: Exponents of the bases used to form the lattice of
Halton boxes. This is either the input J
, or the J
vector
computed by halton.indices
.
bases
: Bases of the Halton sequence used to draw the sample.
hl.bbox
: The bounding box around points in x
used to
draw the sample. See halton.indices
.
Michael Kleinsasser
Aidan McDonald
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