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# Copyright (c) 2005-2010 Roger Bivand and Karl Ove Hufthammer
Rgshhs <- function(fn, xlim=NULL, ylim=NULL, level=4, minarea=0,
shift=FALSE, verbose=TRUE, no.clip = FALSE, properly=FALSE,
avoidGEOS=FALSE, checkPolygons=FALSE) {
if (!is.character(fn)) stop("file name must be character string")
if (length(fn) != 1L) stop("file name must be single character string")
dolim <- FALSE
dolim <- (!is.null(xlim) || !is.null(ylim))
if (!is.null(xlim)) lim <- xlim
else lim <- c(-180, 360)
if (!is.null(ylim)) lim <- c(lim, ylim)
else lim <- c(lim, c(-90, 90))
storage.mode(minarea) <- "double"
polydata <- .Call("Rgshhs", as.character(fn), as.integer(1),
as.logical(dolim), as.numeric(lim), as.integer(level),
minarea, PACKAGE="maptools")
line <- median(polydata$line)
if (verbose) cat("Data are", ifelse(line == 0, "polygon", "line"),
"data\n")
chosen_0 <- .Call("Rgshhs", as.character(fn), as.integer(2),
as.logical(dolim), as.numeric(lim), as.integer(level),
minarea, PACKAGE="maptools")
if (dolim) clip <- .Call("Rgshhs", as.character(fn), as.integer(3),
as.logical(dolim), as.numeric(lim), as.integer(level),
minarea, PACKAGE="maptools")
else clip <- NULL
rgeosI <- rgeosStatus()
if (rgeosI && !avoidGEOS) {
# require(rgeos)
if (!requireNamespace("rgeos", quietly = TRUE))
stop("rgeos required for Rgshhs")
} else {
stopifnot(isTRUE(gpclibPermitStatus()))
if (!requireNamespace("gpclib", quietly = TRUE))
stop("gpclib required for Rgshhs")
# require("gpclib")
}
polys <- .Call("Rgshhs", as.character(fn), as.integer(5),
as.logical(dolim), as.numeric(lim), as.integer(level),
minarea, PACKAGE="maptools")
Antarctica <- which(polydata$area[(chosen_0+1)] > 1.3e+07 &
polydata$area[(chosen_0+1)] < 1.4e+07)
if (length(Antarctica) == 1L) {
if (verbose) cat("Polygon", which(chosen_0 == (Antarctica-1)),
"is Antarctica\n")
if (verbose) cat(" area", polydata$area[Antarctica], "\n")
if (verbose) cat(" dropping south edge to", lim[3], "\n")
crds <- polys[[which(chosen_0 == (Antarctica-1))]]
# if (verbose) print(crds[c(1,2,(nrow(crds)-5):nrow(crds)),])
crds <- rbind(crds[1:(nrow(crds)-2),],
c(0, crds[(nrow(crds)-2),2]), c(0, lim[3]),
c(360, lim[3]), crds[1,,drop=FALSE])
# if (verbose) print(crds[c(1,2,(nrow(crds)-5):nrow(crds)),])
polys[[which(chosen_0 == (Antarctica-1))]] <- crds
}
if (!no.clip && dolim && any(clip == 1) && line == 0) {
limbb <- cbind(c(lim[1], lim[1], lim[2], lim[2], lim[1]),
c(lim[3], lim[4], lim[4], lim[3], lim[3]))
which_null <- NULL
opolys <- vector(mode="list", length=length(polys))
ic <- 1
if (verbose) cat("Rgshhs: clipping", sum(clip), "of",
length(polys), "polygons ...\n")
if (rgeosI && !avoidGEOS) {
limgp <- SpatialPolygons(list(Polygons(list(Polygon(limbb)),
ID="0")))
for (i in seq(along=polys)) {
if (clip[i] == 1) {
tp <- SpatialPolygons(list(Polygons(list(Polygon(
polys[[i]])), ID="1")))
rp0 <- NULL
gI <- rgeos::gIntersection(tp, limgp)
# bug reported 120809 r-sig-geo.20.trevva
if (!is.null(gI) && is(gI, "SpatialCollections"))
gI <- slot(gI, "polyobj")
if (!is.null(gI))
rp0 <- slot(gI, "polygons")[[1]]
rp <- NULL
if (!is.null(rp0))
rp <- lapply(slot(rp0, "Polygons"), slot, "coords")
l <- length(rp)
if (l > 0) {
outl <- vector(mode="list", length=l)
for (j in 1:l)
outl[[j]] <- as(rp[[j]], "matrix")
opolys[[ic]] <- outl
if (i < length(polys)) ic <- ic+1
} else {
which_null <- c(which_null, i)
if (verbose) cat("null polygon: [[", i,
"]]\n", sep="");
}
} else {
opolys[[ic]] <- list(polys[[i]])
if (i < length(polys)) ic <- ic+1
}
}
polys <- opolys[1:ic]
} else {
limgp <- as(limbb, "gpc.poly")
for (i in seq(along=polys)) {
if (clip[i] == 1) {
tp <- as(polys[[i]], "gpc.poly")
rp <- gpclib::intersect(tp, limgp)
l <- length(rp@pts)
if (l > 0) {
outl <- vector(mode="list", length=l)
for (j in 1:l)
outl[[j]] <- as(rp[j], "matrix")
opolys[[ic]] <- outl
if (i < length(polys)) ic <- ic+1
} else {
which_null <- c(which_null, i)
if (verbose) cat("null polygon: [[",i,
"]]\n", sep="");
}
} else {
opolys[[ic]] <- list(polys[[i]])
if (i < length(polys)) ic <- ic+1
}
}
polys <- opolys[1:ic]
}
} else {
for (i in seq(along=polys)) polys[[i]] <- list(polys[[i]])
which_null <- NULL
}
if (!is.null(which_null)) chosen_0 <- chosen_0[-which_null]
chosen_1 <- chosen_0+1
if (line == 0) {
levels <- polydata$level[chosen_1]
if (rgeosI && !avoidGEOS) {
ids <- polydata$id[chosen_1]
containers <- polydata$container[chosen_1]
ancestors <- polydata$ancestor[chosen_1]
tl <- as.list(table(levels))
ntl <- as.integer(names(tl))
mntl <- match(1:4, ntl)
l1 <- which(levels == 1L)
if (length(l1) > 0L) {
c1 <- which(containers == -1L)
if (any(l1 != c1)) warning("containers and levels not coherent")
if (!is.na(mntl[4])) {
wl4 <- which(levels == 4L)
cw4 <- containers[wl4]
mcw4 <- match(cw4, ids)
containers[wl4] <- containers[mcw4]
}
if (!is.na(mntl[3])) {
wl3 <- which(levels == 3L | levels == 4L)
cw3 <- containers[wl3]
mcw3 <- match(cw3, ids)
containers[wl3] <- containers[mcw3]
}
IDs <- ids[l1]
if (is.na(mntl[2])) {
belongs <- as.list(l1)
} else {
belongs <- lapply(1:length(IDs), function(i)
c(i, which(containers == IDs[i])))
}
} else {
stop("no shoreline in selection")
}
holes <- !as.logical(levels %% 2)
nps <- sapply(polys, length)
n <- length(belongs)
Srl <- vector(mode="list", length=n)
for (i in 1:n) {
nParts <- length(belongs[[i]])
srl <- NULL
for (j in 1:nParts) {
this <- belongs[[i]][j]
for (k in 1:nps[this]) {
crds <- polys[[this]][[k]]
if (!identical(crds[1,], crds[nrow(crds),])) {
crds <- rbind(crds, crds[1,,drop=FALSE])
if (verbose)
cat(" closing polygon", this, ":", k, "\n")
}
if (shift) crds[,1] <- ifelse(crds[,1] > 180,
crds[,1] - 360, crds[,1])
if (checkPolygons) {
jres <- list(Polygon(crds))
} else {
jres <- list(Polygon(crds, hole=holes[this]))
}
srl <- c(srl, jres)
}
}
pls0 <- Polygons(srl, ID=IDs[i])
if (checkPolygons) {
Srl[[i]] <- checkPolygonsGEOS(pls0, properly=properly)
} else {
Srl[[i]] <- pls0
}
}
res <- as.SpatialPolygons.PolygonsList(Srl,
proj4string=CRS("+proj=longlat +datum=WGS84"))
polydata <- data.frame(polydata)[chosen_1,]
return(list(polydata=polydata, belongs=belongs, SP=res))
} else {
belongs <- matrix(1:length(chosen_1), ncol=1)
# belonged_to <- as.numeric(rep(NA, length(chosen_1)))
if (level > 1 && any(levels > 1)) {
if (verbose) {
cat("Rgshhs: assigning enclosed polygons to their enclosers\n")
cat(" level tallies:\n")
print(table(levels))
cat("...\n")
}
mlevel <- as.integer(max(levels))
belongs <- matrix(rep(1:length(chosen_1), mlevel), ncol=mlevel)
first_time <- TRUE
for (il in mlevel:2) {
w_il <- which(levels == il)
w_il_1 <- which(levels == (il-1))
if (length(w_il) > 0L) {
if (length(w_il_1) == 1L) {
belongs[w_il, (il-1)] <- w_il_1
if (!first_time) {
prom <- which(!is.na(match(belongs[,il], w_il)))
belongs[prom, (il-1)] <- rep(w_il_1,
length(prom))
}
first_time <- FALSE
} else {
l_1 <- vector(mode="list", length=length(w_il_1))
for (i in 1:length(w_il_1)) {
ii <- w_il_1[i]
lp1 <- as(polys[[ii]][[1]], "gpc.poly")
if (length(polys[[ii]]) > 1L) {
for (j in 2:length(polys[[ii]])) {
lpj <- as(polys[[ii]][[j]], "gpc.poly")
lp1 <- gpclib::append.poly(lp1, lpj)
}
}
l_1[[i]] <- lp1
}
for (i in 1:length(w_il)) {
ii <- w_il[i]
lp1 <- as(polys[[ii]][[1]], "gpc.poly")
if (length(polys[[ii]]) > 1L) {
for (j in 2:length(polys[[ii]])) {
lpj <- as(polys[[ii]][[j]], "gpc.poly")
lp1 <- gpclib::append.poly(lp1, lpj)
}
}
for (j in 1:length(l_1)) {
tp <- gpclib::intersect(l_1[[j]], lp1)
if (length(tp@pts) > 0L) {
belongs[w_il[i], (il-1)] <- w_il_1[j]
if (!first_time) {
prom <- which(!is.na(match(
belongs[,il], w_il[i])))
belongs[prom, (il-1)] <- w_il_1[j]
}
break
}
}
}
first_time <- FALSE
}
}
}
}
if (verbose) cat("Rgshhs: constructing SpatialPolygons ...\n")
holes <- !as.logical(levels %% 2)
nps <- sapply(polys, length)
IDs <- polydata$id[chosen_1[belongs[,1]]]
tab <- table(factor(IDs))
n <- length(tab)
IDss <- names(tab)
reg <- match(IDs, IDss)
new_belongs <- lapply(1:n, function(x) which(x == reg))
Srl <- vector(mode="list", length=n)
for (i in 1:n) {
nParts <- length(new_belongs[[i]])
srl <- NULL
for (j in 1:nParts) {
this <- new_belongs[[i]][j]
for (k in 1:nps[this]) {
crds <- polys[[this]][[k]]
if (!identical(crds[1,], crds[nrow(crds),])) {
crds <- rbind(crds, crds[1,,drop=FALSE])
if (verbose)
cat(" closing polygon", this, ":", k, "\n")
}
if (shift) crds[,1] <- ifelse(crds[,1] > 180,
crds[,1] - 360, crds[,1])
jres <- list(Polygon(crds, hole=holes[this]))
srl <- c(srl, jres)
}
}
Srl[[i]] <- Polygons(srl, ID=IDss[i])
}
res <- as.SpatialPolygons.PolygonsList(Srl,
proj4string=CRS("+proj=longlat +datum=WGS84"))
list(polydata=data.frame(polydata)[chosen_1,], belongs=belongs,
new_belongs=new_belongs, SP=res)
}
} else {
Sll <- lapply(1:length(polys), function(i) {
ID <- as.character(i)
crds <- polys[[i]][[1]]
if (shift) crds[,1] <- ifelse(crds[,1] > 180,
crds[,1] - 360, crds[,1])
Ln <- Line(crds)
Lines(list(Ln), ID=ID)
})
res <- SpatialLines(Sll,
proj4string=CRS("+proj=longlat +datum=WGS84"))
list(SP=res)
}
}
# contributed 101018 by Karl Ove Hufthammer
getRgshhsMap = function (fn = system.file("share/gshhs_c.b",
package = "maptools"), xlim, ylim, level = 1, shift = TRUE,
verbose = TRUE, no.clip = FALSE, properly=FALSE, avoidGEOS=FALSE, checkPolygons=FALSE)
{
# First try fetching the map directly, possibly with negative coordinates.
# Note that some polygons with longitude < 0 use negative coordinates
# (e.g., Great Britain), and some use positve coordinates (e.g., Ireland).
#
# (Must use 'try' here, because for example xlim=c(-40,-10)
# results in an error, while xlim=c(-40,-5) does not.)
map1 = try(Rgshhs(fn, xlim = xlim, ylim = ylim, shift = shift,
level = level, verbose=verbose, no.clip = no.clip,
properly=properly, avoidGEOS=avoidGEOS,
checkPolygons=checkPolygons)$SP)
# Now try fetching the same area using positive coordinates.
xl.west = (xlim + 360)%%360
if (xl.west[2] < xl.west[1])
xl.west[2] = 360
map2 = Rgshhs(fn, xlim = xl.west, ylim = ylim, shift = shift,
level = level, verbose=verbose, no.clip = no.clip,
properly=properly, avoidGEOS=avoidGEOS,
checkPolygons=checkPolygons)$SP
# If there where no polygons with negative coordinates, just
# use the positive coordinates.
if (inherits(map1, "try-error"))
map.union = map2 else { # Else merge the two maps into one.
# First store the original polygon IDs in data frames.
df1 = data.frame(polyID = row.names(map1), stringsAsFactors=FALSE)
row.names(df1) = df1$polyID
map1.spdf = SpatialPolygonsDataFrame(map1, df1)
df2 = data.frame(polyID = row.names(map2), stringsAsFactors=FALSE)
row.names(df2) = df2$polyID
map2.spdf = SpatialPolygonsDataFrame(map2, df2)
# Generate new polygon IDs to avoid duplicate IDs when
# rbinding the two maps.
row.names(map1.spdf) = as.character(seq_along(map1@polygons))
row.names(map2.spdf) = as.character(length(map1@polygons) +
seq_along(map2@polygons))
map.merged = rbind(map1.spdf, map2.spdf)
# Finally, combine all the polygons, using the
# original polyon IDs.
map.union = unionSpatialPolygons(map.merged, map.merged$polyID)
}
map.union
}
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