RandomSpatialSample: uniform random points in a polygon.
HexagonalGridSample: hexagonal grid in a polygon as
sp::spsample(type = "hexagonal"). AdaptiveClusterSample:
Thompson's adaptive cluster sampling with modified Hansen-Hurwitz and
Horvitz-Thompson estimators. QuadtreeGrid: adaptive-resolution
quadtree cells. VoronoiDeclusteringWeights and
CellDeclusteringWeights: declustering weights.
SpatialThinning: randomised thinning to a minimum distance.
MapQualityIndices: ME, MAE, MSE, RMSE, r2 and MEC. Identical to
the Python arm morie.fn.spsampling.
Usage
RandomSpatialSample(n, polygon, seed = 1)
HexagonalGridSample(polygon, cellsize, offset = c(0.5, 0.5))
AdaptiveClusterSample(y, initial = NULL, threshold, n = NULL, seed = 1)
QuadtreeGrid(points, bbox, capacity = 4L, max_depth = 8L)
VoronoiDeclusteringWeights(points, bbox)
CellDeclusteringWeights(points, cell_size, origin = c(0, 0))
SpatialThinning(points, min_dist, reps = 10L, seed = 1)
MapQualityIndices(z, zhat, pi = NULL, N = NULL)Arguments
- n
Sample size.
- polygon
Two-column matrix of polygon vertices.
- seed
Philox seed.
- cellsize
Hexagon spacing.
- offset
Lattice offset (fractions of a cell).
- y
Population grid (matrix).
- initial
Two-column matrix of initial cells (0-based row, col), or NULL.
- threshold
Condition value.
- points
Two-column matrix of points.
- bbox
Box (xmin, ymin, xmax, ymax).
- capacity, max_depth
Quadtree leaf capacity and depth limit.
- cell_size, origin
Declustering cell size and grid origin.
- min_dist, reps
Thinning distance and passes.
- z, zhat
Observations and predictions.
- pi, N
Inclusion probabilities and population size.
References
Thompson, S. K. (1990). Adaptive cluster sampling. JASA 85, 1050-1059.
Aiello-Lammens, M. E. et al. (2015). spThin: an R package for spatial thinning of species occurrence records. Ecography 38, 541-545.
Deutsch, C. V. (1989). DECLUS: a Fortran 77 program for determining optimum spatial declustering weights. Computers and Geosciences 15, 325-332.
Brus, D. J. (2022). Spatial Sampling with R. CRC Press.