ggmap: Grab a map.

Description

ggmap is a smart function which queries the Google Maps server or OpenStreetMap server for a map at a certain location at a certain spatial zoom.

Usage

ggmap(location = "houston", lonR, latR,
    center = c(lat = 29.7632836, lon = -95.3632715),
    regularize = TRUE, type = c("color", "bw"),
    rgbcoefs = c(0, 1, 0), zoom = 10, maptype = "terrain",
    source = c("google", "osm"), verbose = FALSE,
    destfile = "ggmapTemp.jpg", n_pix = 640,
    scale = OSM_scale_lookup(zoom), raster = TRUE, ...)

Arguments

location

a character string containing the name of the location of interest

lonR

longitude range (only for OpenStreetMaps)

latR

latitude range (only for OpenStreetMaps)

center

named numeric vector of latitude and longitude specifying the center of the image

regularize

logical; should the map grid be regularized?

type

'color' for a color map, 'bw' for a black and white map

rgbcoefs

when 'bw' is specified, conversions coefficients to use. see ?ReadImages::rgb2grey

zoom

level of zoom, an integer 0 (whole world) to 19 (higest zoom), default value 10

maptype

any of 'roadmap', 'mobile', 'satellite', 'terrain', 'hybrid', 'mapmaker-roadmap', 'mapmaker-hybrid'

source

'google' or 'osm' (OpenStreetMaps)

verbose

logical; should function message user?

destfile

character; name of file to save downloaded map

n_pix

numeric; number of pixels in map

scale

numeric; scale of OpenStreetMap, see ?GetMap

raster

logical; use geom_raster?

...

Value

a data.frame with columns latitude, longitude, and fill

Examples

Run this code

WashingtonMap_df <- ggmap(location = 'washington', verbose = TRUE)
str(WashingtonMap_df)
ggmapplot(WashingtonMap_df)

lonR <- c(-97.12008, -97.11836)
latR <- c(31.54765, 31.54911)
osm <- ggmap(latR = latR, lonR = lonR, source = 'osm', scale = 1000)
ggmapplot(osm)

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