sf_summarise.R

library(dplyr)
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union
library(sf)
#> Linking to GEOS 3.6.1, GDAL 2.2.0, proj.4 4.9.3
library(ggplot2)
library(spData)

d <- world %>% 
  group_by(continent) %>% 
  summarize(pop = sum(pop, na.rm = TRUE), country_n = n())

d
#> Simple feature collection with 8 features and 3 fields
#> geometry type:  GEOMETRY
#> dimension:      XY
#> bbox:           xmin: -180 ymin: -90 xmax: 180 ymax: 83.64513
#> epsg (SRID):    4326
#> proj4string:    +proj=longlat +datum=WGS84 +no_defs
#> # A tibble: 8 x 4
#>                 continent        pop country_n              geom
#>                     <chr>      <dbl>     <int>  <simple_feature>
#> 1                  Africa 1147005839        51 <MULTIPOLYGON...>
#> 2              Antarctica          0         1 <MULTIPOLYGON...>
#> 3                    Asia 4306025131        47 <MULTIPOLYGON...>
#> 4                  Europe  739178065        39 <MULTIPOLYGON...>
#> 5           North America  565318889        18 <MULTIPOLYGON...>
#> 6                 Oceania   37422867         7 <MULTIPOLYGON...>
#> 7 Seven seas (open ocean)          0         1 <POLYGON((68....>
#> 8           South America  414017917        13 <MULTIPOLYGON...>

ggplot(d) +
  geom_sf(aes(geometry = geom, fill = continent))
#> type is 0
#> Error in CPL_gdal_dimension(st_geometry(x), NA_if_empty): writing this sf type is not supported, please file an issue