Let geom_sf() remove rows when shape, size or colour is NA

NEWS.md

@@ -55,6 +55,8 @@
 
 * `stat_density2d()` can now take an `adjust` parameter to scale the default bandwidth. (#2860, @haleyjeppson)
 
+* `geom_sf()` now removes rows that contain missing `shape`/`size`/`colour` (#3483, @yutannihilation)
+
 # ggplot2 3.2.1
 
 This is a patch release fixing a few regressions introduced in 3.2.0 as well as

R/geom-sf.R

@@ -97,6 +97,8 @@ GeomSf <- ggproto("GeomSf", Geom,
                     stroke = 0.5
                   ),
 
+  non_missing_aes = c("size", "shape", "colour"),
+
   draw_panel = function(data, panel_params, coord, legend = NULL,
                         lineend = "butt", linejoin = "round", linemitre = 10) {
     if (!inherits(coord, "CoordSf")) {

tests/testthat/test-geom-sf.R

@@ -64,3 +64,36 @@ test_that("geom_sf_text() and geom_sf_label() draws correctly", {
     ggplot() + geom_sf_label(data = nc_3857, aes(label = NAME))
   )
 })
+
+test_that("geom_sf() removes rows containing missing aes", {
+  skip_if_not_installed("sf")
+  if (packageVersion("sf") < "0.5.3") skip("Need sf 0.5.3")
+
+  grob_xy_length <- function(x) {
+    g <- layer_grob(x)[[1]]
+    c(length(g$x), length(g$y))
+  }
+
+  pts <- sf::st_sf(
+    geometry = sf::st_sfc(sf::st_point(0:1), sf::st_point(1:2)),
+    size = c(1, NA),
+    shape = c("a", NA),
+    colour = c("red", NA)
+  )
+
+  p <- ggplot(pts) + geom_sf()
+  expect_warning(
+    expect_identical(grob_xy_length(p + aes(size = size)), c(1L, 1L)),
+    "Removed 1 rows containing missing values"
+  )
+  expect_warning(
+    expect_identical(grob_xy_length(p + aes(shape = shape)), c(1L, 1L)),
+    "Removed 1 rows containing missing values"
+  )
+  # default colour scale maps a colour even to a NA, so identity scale is needed to see if NA is removed
+  expect_warning(
+    expect_identical(grob_xy_length(p + aes(colour = colour) + scale_colour_identity()),
+                     c(1L, 1L)),
+    "Removed 1 rows containing missing values"
+  )
+})