Description Usage Arguments Details Value Author(s) References See Also Examples
Draw samples (point locations) from SpatialPoints
, SpatialLines
,
SpatialPolygons
, and the *DataFrame
varieties of each.
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x |
A spatial object. Methods are implemented for |
n |
Desired sample size. Some |
type |
Character, naming the type of sample to draw. Valid
|
... |
Optional arguments passed to underlying sample type method. See DETAILS. |
This is a S4 generic method for types SpatialPoints*
, SpatialLines*
,
and SpatialPolygons*
objects.
BAS, GRTS, SRS, HIP
are fixed-size designs (return exactly n
points).
The SSS
algorithm applied to Line and Point is fixed-sized. The SSS
method
applied to Polygon frames is variable-sized.
Options which determine characteristics of each
sample time are passed via ...
. For example,
spacing and "shape" of the grid in sss.*
are controlled via
spacing=
and triangular=
, while the
J
parameter (which determine box sizes)
is passed to hip.*
. See documentation for
hip.*
, bas.*
, sss.*
, grts.*
, and sss.*
for the full list of
parameters which determine sample characteristics.
A SpatialPointsDataFrame
object. At a minimum, the data frame
embedded in the SpatialPoints
object contains a column named siteID
which
numbers the points, and geometryID
which contains the ID of the
spatial object from which the point was drawn.
If x
is a Spatial*DataFrame
, the return's data
frame contains all attributes of x
evaluated at the locations of the sample points.
Certain sampling routine add attributes
that are pertinent to the design. For example, the grts.*
routines add
a pointType
attribute. See documentation for the underlying sampling routine
to interpret extra output point attributes.
Trent McDonald
Robertson, B.L., J. A. Brown, T. L. McDonald, and P. Jaksons (2013) "BAS: Balanced Acceptance Sampling of Natural Resources", Biometrics, v69, p. 776-784.
Stevens D. L. Jr. and A. R. Olsen (2004) "Spatially Balanced Sampling of Natural Resources", Journal of the American Statistical Association, v99, p. 262-278.
bas.polygon
, bas.line
, bas.point
,
hip.polygon
, hip.point
,
sss.polygon
, sss.line
, sss.point
,
grts.polygon
, grts.line
, grts.point
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