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adds runifpoint #1204

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adds runifpoint #1204

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acb35f1
adds runifpoint
Nowosad Nov 24, 2019
fec8a53
shows not working spatstat sampling
Nowosad Dec 8, 2019
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36 changes: 28 additions & 8 deletions R/sample.R
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Original file line number Diff line number Diff line change
Expand Up @@ -71,18 +71,18 @@
#' @export
st_sample = function(x, size, ..., type = "random", exact = TRUE) {
x = st_geometry(x)
if (any(size %% 1 != 0))
if (!missing(size) && any(size %% 1 != 0))
stop("size should be an integer")
if (length(size) > 1) { # recurse:
if (!missing(size) && length(size) > 1) { # recurse:
size = rep(size, length.out = length(x))
ret = lapply(1:length(x), function(i) st_sample(x[i], size[i], type = type, exact = exact, ...))
res = st_set_crs(do.call(c, ret), st_crs(x))
} else {
res = switch(max(st_dimension(x)) + 1,
st_multipoints_sample(do.call(c, x), size, ..., type = type),
st_ll_sample(st_cast(x, "LINESTRING"), size, ..., type = type),
st_poly_sample(x, size, ..., type = type))
if (exact & type == "random" & all(st_geometry_type(res) == "POINT")) {
st_poly_sample(x, ..., size, type = type))
if (!missing(size) && exact && type == "random" && all(st_geometry_type(res) == "POINT")) {
diff = size - length(res)
if(diff > 0) { # too few points
res_additional = st_sample_exact(x = x, size = diff, ..., type = type)
Expand All @@ -95,14 +95,14 @@ st_sample = function(x, size, ..., type = "random", exact = TRUE) {
res
}

st_poly_sample = function(x, size, ..., type = "random",
st_poly_sample = function(x, ..., size, type = "random",
offset = st_sample(st_as_sfc(st_bbox(x)), 1)[[1]]) {

a0 = as.numeric(st_area(st_make_grid(x, n = c(1,1))))
a1 = as.numeric(sum(st_area(x)))
# st_polygon(list(rbind(c(-180,-90),c(180,-90),c(180,90),c(-180,90),c(-180,-90))))
# for instance has 0 st_area
if (is.finite(a0) && is.finite(a1) && a0 > a0 * 0.0 && a1 > a1 * 0.0)
if (is.finite(a0) && is.finite(a1) && a0 > a0 * 0.0 && a1 > a1 * 0.0 && !missing(size))
size = round(size * a0 / a1)
bb = st_bbox(x)

Expand Down Expand Up @@ -130,8 +130,28 @@ st_poly_sample = function(x, size, ..., type = "random",
runif(size, bb[2], bb[4])
m = cbind(lon, lat)
st_sfc(lapply(seq_len(nrow(m)), function(i) st_point(m[i,])), crs = st_crs(x))
} else
stop(paste("sampling type", type, "not implemented for polygons"))
} else {
if (!requireNamespace("spatstat", quietly = TRUE)){
stop("package spatstat required, please install it first")
}
spatstat_fun = try(get(paste0("r", type), asNamespace("spatstat")), silent = TRUE)
if(inherits(spatstat_fun, "try-error")){
# stop(paste0("r", type), " is not an exported function from spatstat.")
stop(paste("sampling type", type, "not implemented for polygons"))
}
if (!requireNamespace("maptools", quietly = TRUE)){
stop("package maptools required, please install it first")
}
rslt = try(spatstat_fun(..., win = maptools::as.owin.SpatialPolygons(as(x, "Spatial"))), silent = TRUE)
if(inherits(rslt, "try-error")){
stop("The spatstat function ", paste0("r", type),
" did not return a valid result. Consult the help file.\n",
"Error message from spatstat:\n", rslt)
}
rslt = st_as_sf(rslt)
rslt = st_collection_extract(rslt, "POINT")
st_geometry(rslt)
}
pts[lengths(st_intersects(pts, x)) > 0]
}

Expand Down