Better ranges for coord_map gridlines. Fixes #689

tidyverse · Oct 22, 2012 · f89e051 · f89e051
1 parent ee8ec2a
commit f89e051
Showing 1 changed file with 6 additions and 4 deletions.
diff --git a/R/coord-map.r b/R/coord-map.r
@@ -139,10 +139,12 @@ coord_render_bg.map <- function(coord, details, theme) {
   yrange <- expand_range(details$y.range, 0.2)
 
   # Limit ranges so that lines don't wrap around globe
-  xrange[xrange < 0]   <- 0
-  xrange[xrange > 360] <- 360
-  yrange[yrange < -90] <- -90
-  yrange[yrange > 90]  <- 90
+  xmid <- mean(xrange)
+  ymid <- mean(yrange)
+  xrange[xrange < xmid - 180] <- xmid - 180
+  xrange[xrange > xmid + 180] <- xmid + 180
+  yrange[yrange < ymid - 90] <- ymid - 90
+  yrange[yrange > ymid + 90] <- ymid + 90
 
   xgrid <- with(details, expand.grid(
     y = c(seq(yrange[1], yrange[2], len = 50), NA),