st_simplify outputs the input geometry with no simplification
It has changed it, there's now a mix of POLYGON and MULTIPOLYGON geometries, but no change in the underlying coordinates. You have to use the dTolerance argument: nrow(st_coordinates(nc)) [1] 2529 nrow(st_coordinates(st_cast(nc_simplfy))) [1] 2529 nrow(st_coordinates(st_cast(st_simplify(nc, dTolerance = 1000)))) [1] 1941 It still might change the geometry with dTolerance = 0 (the default), in that case it will remove vertices that are collinear (unnecessarily dense straight lines, reduce to two-vertex edges). I only learnt that recently. HTH
On Mon, Jul 22, 2019 at 8:15 PM Hugo Costa <hugoagcosta at gmail.com> wrote:
Dear list,
function st_simplify outputs exactly the same geometry as the input. This
is an example:
library(sf)
nc = st_read(system.file("shape/nc.shp", package="sf"))
nc <- nc %>% st_transform(3857)
plot(st_geometry(nc))
nc_simplfy<-st_simplify(nc)
plot(st_geometry(nc_simplfy))
However, I'm quite sure some days ago st_simpliffy was working as expected.
Could it be something wrong in my machine? What am I missing?
sessionInfo()
R version 3.5.3 (2019-03-11)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows >= 8 x64 (build 9200)
Matrix products: default
locale:
[1] LC_COLLATE=Portuguese_Portugal.1252 LC_CTYPE=Portuguese_Portugal.1252
LC_MONETARY=Portuguese_Portugal.1252 LC_NUMERIC=C
[5] LC_TIME=Portuguese_Portugal.1252
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] sf_0.7-3
loaded via a namespace (and not attached):
[1] compiler_3.5.3 magrittr_1.5 class_7.3-15 DBI_1.0.0
tools_3.5.3 units_0.6-2 Rcpp_1.0.1 grid_3.5.3 e1071_1.7-0.1
[10] classInt_0.3-1
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