Hello
I'm working with a number of lines that cross back and forth of 180. When working in a projection (e.g. 3571), this isn't an issue. But, if I want to add those lines to a leaflet map, I need to transform to 4326. With sp::spTransform() I've been able to pass along the +lon_wrap=180 specification and this converts the longitude coordinates to 0-360 which leaflet respects
library(sp)
library(sf)
library(magrittr)
library(leaflet)
l <- "LINESTRING(-150.5 57.0,-160.5 57.0,-170.5 57.0,179.5 57.0,169.5 57.0,159.5 57.0)" %>%
sf::st_as_sfc(crs = "+init=epsg:4326")
l_sp <- as(l,"Spatial")
l_sp <- sp::spTransform(l_sp,"+proj=longlat +datum=WGS84 +lon_wrap=180")
sp::proj4string(l_sp)
bbox(l_sp)
m <- l_sp %>%
leaflet() %>%
addProviderTiles("Esri.OceanBasemap") %>%
addPolylines(weight = 4, opacity = 0.35, color = 'black')
m
However, when I try to accomplish the same thing with sf, the +lon_wrap appears to be ignored.
m <- l %>%
sf::st_transform("+proj=longlat +datum=WGS84 +lon_wrap=180") %>%
leaflet() %>%
addProviderTiles("Esri.OceanBasemap") %>%
addPolylines(weight = 4, opacity = 0.35, color = 'black')
m
l %>% sf::st_transform("+proj=longlat +datum=WGS84 +lon_wrap=180") %>%
sf::st_crs()
l %>% sf::st_transform("+proj=longlat +datum=WGS84 +lon_wrap=180") %>%
sf::st_bbox()
> sessionInfo()
R version 3.3.3 (2017-03-06)
Platform: x86_64-apple-darwin13.4.0 (64-bit)
Running under: macOS Sierra 10.12.3
leaflet_1.1.0.9000
sp_1.2-4
sf_0.3-4
Is this a known/expected difference between sp::spTransform and sf::st_transform? Is there a different approach I should be taking?
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