R version 4.0.0 (2020-04-24) -- "Arbor Day"
Copyright (C) 2020 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

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> suppressPackageStartupMessages(library(sf))
> 
> nc = st_read(system.file("shape/nc.shp", package="sf"), "nc", crs = 4267,
+ 	agr = c(AREA = "aggregate", PERIMETER = "aggregate", CNTY_ = "identity",
+ 		CNTY_ID = "identity", NAME = "identity", FIPS = "identity", FIPSNO = "identity",
+ 		CRESS_ID = "identity", BIR74 = "aggregate", SID74 = "aggregate", NWBIR74 = "aggregate",
+ 		BIR79 = "aggregate", SID79 = "aggregate", NWBIR79  = "aggregate"), quiet = TRUE)
> 
> st_is_valid(nc)
  [1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
 [16] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
 [31] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
 [46] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
 [61] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
 [76] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
 [91] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
> 
> st_is_simple(nc)
  [1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
 [16] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
 [31] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
 [46] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
 [61] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
 [76] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
 [91] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
> 
> nc_tr = st_transform(nc, 3857)
> 
> x = st_buffer(nc_tr, 1000)
> 
> x = st_boundary(nc)
> 
> x = st_convex_hull(nc)
> 
> x = st_simplify(nc_tr, dTolerance = 1e4)
> 
> x = st_simplify(nc_tr, preserveTopology = TRUE)
> 
> if (sf:::CPL_geos_version() >= "3.4.0")
+ 	x = st_triangulate(nc_tr)
> 
> mls = st_multilinestring(list(matrix(c(0,0,0,1,1,1,0,0),,2,byrow=TRUE)))
> x = st_polygonize(mls)
> 
> x = st_segmentize(nc_tr, 5e4)
> 
> try(x <- st_segmentize(nc_tr, -0.1))
Error in CPL_gdal_segmentize(x, dfMaxLength) : 
  argument dfMaxLength should be positive

> 
> x = st_centroid(nc_tr)
Warning message:
In st_centroid.sf(nc_tr) :
  st_centroid assumes attributes are constant over geometries of x
> x = st_point_on_surface(nc_tr)
Warning message:
In st_point_on_surface.sf(nc_tr) :
  st_point_on_surface assumes attributes are constant over geometries of x
> 
> a = nc[1:5,]
> b = nc[4:10,]
> 
> x <- st_intersection(a[1,] ,b)
although coordinates are longitude/latitude, st_intersection assumes that they are planar
Warning message:
attribute variables are assumed to be spatially constant throughout all geometries 
> 
> u = st_union(b) 
> 
> x <- st_intersection(st_geometry(a), st_geometry(u))
although coordinates are longitude/latitude, st_intersection assumes that they are planar
> 
> x = st_union(a[1,], b)
although coordinates are longitude/latitude, st_union assumes that they are planar
Warning message:
attribute variables are assumed to be spatially constant throughout all geometries 
> 
> x = st_union(a, st_union(b))
although coordinates are longitude/latitude, st_union assumes that they are planar
Warning message:
attribute variables are assumed to be spatially constant throughout all geometries 
> 
> x = st_difference(a[1,], b)
although coordinates are longitude/latitude, st_difference assumes that they are planar
Warning message:
attribute variables are assumed to be spatially constant throughout all geometries 
> 
> x = st_difference(a, st_union(b))
although coordinates are longitude/latitude, st_difference assumes that they are planar
Warning message:
attribute variables are assumed to be spatially constant throughout all geometries 
> 
> x = st_sym_difference(a[1,], b)
although coordinates are longitude/latitude, st_sym_difference assumes that they are planar
Warning message:
attribute variables are assumed to be spatially constant throughout all geometries 
> 
> x = st_sym_difference(a, st_union(b))
although coordinates are longitude/latitude, st_sym_difference assumes that they are planar
Warning message:
attribute variables are assumed to be spatially constant throughout all geometries 
> 
> x = st_drivers()
> #cat(paste("GDAL has", nrow(x), "drivers\n"))
> 
> # GEOS ops:
> 
> st_relate(a, b)
although coordinates are longitude/latitude, st_relate assumes that they are planar
     [,1]        [,2]        [,3]        [,4]        [,5]        [,6]       
[1,] "FF2FF1212" "FF2FF1212" "FF2FF1212" "FF2FF1212" "FF2FF1212" "FF2FF1212"
[2,] "FF2FF1212" "FF2FF1212" "FF2FF1212" "FF2FF1212" "FF2FF1212" "FF2FF1212"
[3,] "FF2FF1212" "FF2FF1212" "FF2FF1212" "FF2FF1212" "FF2FF1212" "FF2FF1212"
[4,] "2FFF1FFF2" "FF2FF1212" "FF2FF1212" "FF2F11212" "FF2FF1212" "FF2FF1212"
[5,] "FF2FF1212" "2FFF1FFF2" "FF2F11212" "FF2FF1212" "FF2FF1212" "FF2F11212"
     [,7]       
[1,] "FF2FF1212"
[2,] "FF2FF1212"
[3,] "FF2F11212"
[4,] "FF2FF1212"
[5,] "FF2FF1212"
> 
> st_disjoint(a, b)
although coordinates are longitude/latitude, st_intersects assumes that they are planar
Sparse geometry binary predicate list of length 5, where the predicate was `disjoint'
 1: 1, 2, 3, 4, 5, 6, 7
 2: 1, 2, 3, 4, 5, 6, 7
 3: 1, 2, 3, 4, 5, 6
 4: 2, 3, 5, 6, 7
 5: 1, 4, 5, 7
> 
> st_touches(a, b)
although coordinates are longitude/latitude, st_touches assumes that they are planar
Sparse geometry binary predicate list of length 5, where the predicate was `touches'
 1: (empty)
 2: (empty)
 3: 7
 4: 4
 5: 3, 6
> 
> st_crosses(a, b)
although coordinates are longitude/latitude, st_crosses assumes that they are planar
Sparse geometry binary predicate list of length 5, where the predicate was `crosses'
 1: (empty)
 2: (empty)
 3: (empty)
 4: (empty)
 5: (empty)
> 
> st_within(a, b)
although coordinates are longitude/latitude, st_within assumes that they are planar
Sparse geometry binary predicate list of length 5, where the predicate was `within'
 1: (empty)
 2: (empty)
 3: (empty)
 4: 1
 5: 2
> 
> st_contains(a, b)
although coordinates are longitude/latitude, st_contains assumes that they are planar
Sparse geometry binary predicate list of length 5, where the predicate was `contains'
 1: (empty)
 2: (empty)
 3: (empty)
 4: 1
 5: 2
> 
> st_overlaps(a, b)
although coordinates are longitude/latitude, st_overlaps assumes that they are planar
Sparse geometry binary predicate list of length 5, where the predicate was `overlaps'
 1: (empty)
 2: (empty)
 3: (empty)
 4: (empty)
 5: (empty)
> 
> st_equals(a, b)
Sparse geometry binary predicate list of length 5, where the predicate was `equals'
 1: (empty)
 2: (empty)
 3: (empty)
 4: 1
 5: 2
> 
> st_covers(a, b)
although coordinates are longitude/latitude, st_covers assumes that they are planar
Sparse geometry binary predicate list of length 5, where the predicate was `covers'
 1: (empty)
 2: (empty)
 3: (empty)
 4: 1
 5: 2
> 
> st_covered_by(a, b)
although coordinates are longitude/latitude, st_covered_by assumes that they are planar
Sparse geometry binary predicate list of length 5, where the predicate was `covered_by'
 1: (empty)
 2: (empty)
 3: (empty)
 4: 1
 5: 2
> 
> st_equals_exact(a, b, 0.01)
Sparse geometry binary predicate list of length 5, where the predicate was `equals_exact'
 1: (empty)
 2: (empty)
 3: (empty)
 4: 1
 5: 2
> 
> # st_is_within_distance(a, b, 2)
> 
> st_geometry_type(st_sfc(st_point(1:2), st_linestring(matrix(1:4,2,2))))
[1] POINT      LINESTRING
18 Levels: GEOMETRY POINT LINESTRING POLYGON MULTIPOINT ... TRIANGLE
> 
> st_geometry_type(st_sfc(st_point(1:2), st_linestring(matrix(1:4,2,2))), by_geometry = FALSE)
[1] GEOMETRY
18 Levels: GEOMETRY POINT LINESTRING POLYGON MULTIPOINT ... TRIANGLE
> 
> st_zm(list(st_point(1:3), st_linestring(matrix(1:6,2,3))))
[[1]]
POINT (1 2)

[[2]]
LINESTRING (1 3, 2 4)

> 
> st_zm(list(st_point(1:2), st_linestring(matrix(1:6,3,2))), add = TRUE, "Z")
[[1]]
POINT (1 2)

[[2]]
LINESTRING (1 4, 2 5, 3 6)

> 
> st_transform(st_sfc(st_point(c(0,0)), crs=4326), st_crs("+proj=geocent"))[[1]]
POINT Z (6378137 0 0)
> 
> cbind(st_area(nc_tr[1:5,]), a$AREA)
           [,1]  [,2]
[1,] 1760244967 0.114
[2,]  946435667 0.061
[3,] 2202248253 0.143
[4,] 1074351919 0.070
[5,] 2352539533 0.153
> 
> st_area(st_polygon(list(rbind(c(0,0), c(1,0), c(1,1), c(0,1), c(0,0)))))
[1] 1
> 
> st_length(st_linestring(rbind(c(0,0),c(0,1))))
[1] 1
> 
> st_length(st_multilinestring(list(rbind(c(0,0),c(0,1)))))
[1] 1
> 
> try(st_length(st_polygon(list(rbind(c(0,0), c(1,0), c(1,1), c(0,1), c(0,0))))))
[1] 0
> 
> st_area(st_multilinestring(list(rbind(c(0,0),c(0,1)))))
[1] 0
> 
> # adds the (0.5 0.5) node:
> st_union(st_multilinestring(list(rbind(c(0,0),c(1,1)), rbind(c(0,1), c(1,0)))))
MULTILINESTRING ((0 0, 1 1), (0 1, 1 0))
> 
> p1 = st_point(c(7,52))
> p2 = st_point(c(-30,20))
> sfc = st_sfc(p1, p2)
> try(st_buffer(sfc, units::set_units(1000, km))) # error: no crs
Error in st_buffer.sfc(sfc, units::set_units(1000, km)) : 
  x does not have a crs set: can't convert units
> sfc = st_sfc(p1, p2, crs = 4326)
> try(st_buffer(sfc, units::set_units(1000, km))) # error: wrong units
Error : cannot convert km into °
In addition: Warning message:
In st_buffer.sfc(sfc, units::set_units(1000, km)) :
  st_buffer does not correctly buffer longitude/latitude data
> if (version$os == "linux-gnu") { # FIXME: why does this break on windows - degree symbol?
+   x = st_buffer(sfc, units::set_units(0.1, rad))      # OK: will convert to arc_degrees
+ }
Warning message:
In st_buffer.sfc(sfc, units::set_units(0.1, rad)) :
  st_buffer does not correctly buffer longitude/latitude data
> x = st_transform(sfc, 3857)
> x = st_buffer(x, units::set_units(1000, km)) # success
> 
> cr = st_as_sfc("CIRCULARSTRING(0 0,1 0,1 1)")
> cr1 = st_sf(a = 1, geometry = cr)
> plot(cr)
> st_as_grob(cr[[1]])
lines[GRID.lines.1] 
> 
> x = st_as_sfc("MULTISURFACE(CURVEPOLYGON(COMPOUNDCURVE(LINESTRING(-159.399779123 22.226016471, -159.399699153 22.226276431, -159.398736217 22.226118372, -159.398260872 22.226095318, -159.398140792 22.2260564590001, -159.398163058 22.2257268010001, -159.397882642 22.225394244, -159.397397157 22.225057335, -159.397318825 22.2251780230001, -159.396993115 22.225177984, -159.396748242 22.2248808800001, -159.396901679 22.224770398, -159.396876329 22.224673093, -159.399167008 22.224731392, -159.399502204 22.225551382), CIRCULARSTRING(-159.399502204 22.225551382, -159.399622762077 22.2257930044972, -159.399779123 22.226016471))))")
> mp <- x[[1]] %>% st_cast("MULTIPOLYGON")
> 
> x = st_as_sfc("COMPOUNDCURVE(CIRCULARSTRING(0 0, 1 1, 1 0),(1 0, 0 1))")
> ls <- x[[1]] %>% st_cast()
> class(ls)
[1] "XY"         "LINESTRING" "sfg"       
> 
> is.na(st_bbox(ls))
[1] FALSE
> 
> mp = st_combine(st_buffer(st_sfc(lapply(1:3, function(x) st_point(c(x,x)))), 0.2 * 1:3))
> plot(st_centroid(mp), add = TRUE, col = 'red') # centroid of combined geometry
> plot(st_centroid(mp, of_largest_polygon = TRUE), add = TRUE, col = 'blue', pch = 3) # center of largest sub-polygon
> 
> x = st_sfc(st_polygon(list(rbind(c(0,0),c(0.5,0),c(0.5,0.5),c(0.5,0),c(1,0),c(1,1),c(0,1),c(0,0)))))
> suppressWarnings(st_is_valid(x))
[1] FALSE
> y = st_make_valid(x)
> y = st_make_valid(x[[1]])
> y = st_make_valid(st_sf(a = 1, geom = x))
> st_is_valid(y)
[1] TRUE
> 
> proc.time()
   user  system elapsed 
  1.160   0.072   1.229