ggmap (version 4.0.0)

gglocator: Locator for ggplot objects

Description

Locator for ggplot objects (Note : only accurate when extent = "normal" when using ggmap.)

Usage

gglocator(n = 1, message = FALSE, mercator = TRUE, ...)

Value

a data frame with columns according to the x and y aesthetics

Arguments

n

number of points to locate.

message

unused

mercator

logical flag; should the plot be treated as using the projection common to most web map services? Set to FALSE if the axes on the plot use a linear scale.

...

additional arguments (including deprecated, e.g. xexpand)

Author

Tyler Rinker, Baptiste Auguie, DWin, David Kahle, \@Nikolai-Hlubek and \@mvkorpel.

Examples

if (interactive()) {

# only run for interactive sessions
df <- expand.grid(x = 0:-5, y = 0:-5)

ggplot(df, aes(x, y)) + geom_point() +
  annotate(geom = "point", x = -2, y = -2, colour = "red")

(pt <- gglocator(mercator = FALSE)) # click red point

last_plot() +
  annotate("point", pt$x, pt$y, color = "blue", size = 3, alpha = .5)

hdf <- get_map("houston, texas")
ggmap(hdf, extent = "normal")
(pt <- gglocator(mercator = TRUE))
last_plot() +
  annotate("point", pt$lon, pt$lat, color = "blue", size = 3, alpha = .5)

}