qmplot: Quick map plot

In dkahle/ggmap: Spatial Visualization with ggplot2

Quick map plot

Description

qmplot() is the ggmap equivalent to the ggplot2 function qplot and allows for the quick plotting of maps with data/models/etc.

Usage

qmplot(
  x,
  y,
  ...,
  data,
  zoom,
  source = "stadia",
  maptype = "stamen_toner_lite",
  extent = "device",
  legend = "right",
  padding = 0.02,
  force = FALSE,
  darken = c(0, "black"),
  mapcolor = "color",
  facets = NULL,
  margins = FALSE,
  geom = "auto",
  stat = list(NULL),
  position = list(NULL),
  xlim = c(NA, NA),
  ylim = c(NA, NA),
  main = NULL,
  f = 0.05,
  xlab = "Longitude",
  ylab = "Latitude"
)

Arguments

x	longitude values
y	latitude values
...	other aesthetics passed for each layer
data	data frame to use (optional). If not specified, will create one, extracting vectors from the current environment.
zoom	map zoom, see get_map()
source	map source, see get_map()
maptype	map type, see get_map()
extent	how much of the plot should the map take up? "normal", "panel", or "device" (default)
legend	"left", "right" (default), "bottom", "top", "bottomleft", "bottomright", "topleft", "topright", "none" (used with extent = "device")
padding	distance from legend to corner of the plot (used with extent = "device")
force	force new map (don't use archived version)
darken	vector of the form c(number, color), where number is in (0,1) and color is a character string indicating the color of the darken. 0 indicates no darkening, 1 indicates a black-out.
mapcolor	color ("color") or black-and-white ("bw")
facets	faceting formula to use. Picks facet_wrap() or facet_grid() depending on whether the formula is one sided or two-sided
margins	whether or not margins will be displayed
geom	character vector specifying geom to use. defaults to "point"
stat	character vector specifying statistics to use
position	character vector giving position adjustment to use
xlim	limits for x axis
ylim	limits for y axis
main	character vector or expression for plot title
f	number specifying the fraction by which the range should be extended
xlab	character vector or expression for x axis label
ylab	character vector or expression for y axis label

Examples

## Not run:  # these are skipped to conserve R check time

qmplot(lon, lat, data = crime)


# only violent crimes
violent_crimes <- subset(crime,
  offense != "auto theft" &
  offense != "theft" &
  offense != "burglary"
)

# rank violent crimes
violent_crimes$offense <- factor(
  violent_crimes$offense,
  levels = c("robbery", "aggravated assault", "rape", "murder")
)

# restrict to downtown
violent_crimes <- subset(violent_crimes,
  -95.39681 <= lon & lon <= -95.34188 &
   29.73631 <= lat & lat <=  29.78400
)

theme_set(theme_bw())

qmplot(lon, lat, data = violent_crimes, colour = offense,
  size = I(3.5), alpha = I(.6), legend = "topleft")

qmplot(lon, lat, data = violent_crimes, geom = c("point","density2d"))
qmplot(lon, lat, data = violent_crimes) + facet_wrap(~ offense)
qmplot(lon, lat, data = violent_crimes, extent = "panel") + facet_wrap(~ offense)
qmplot(lon, lat, data = violent_crimes, extent = "panel", colour = offense, darken = .4) +
  facet_wrap(~ month)




qmplot(long, lat, xend = long + delta_long,
  color = I("red"), yend = lat + delta_lat, data = seals,
  geom = "segment", zoom = 5)

qmplot(long, lat, xend = long + delta_long, maptype = "stamen_watercolor",
  yend = lat + delta_lat, data = seals,
  geom = "segment", zoom = 6)

qmplot(long, lat, xend = long + delta_long, maptype = "stamen_terrain",
  yend = lat + delta_lat, data = seals,
  geom = "segment", zoom = 6)


qmplot(lon, lat, data = wind, size = I(.5), alpha = I(.5)) +
  ggtitle("NOAA Wind Report Sites")

# thin down data set...
s <- seq(1, 227, 8)
thinwind <- subset(wind,
  lon %in% unique(wind$lon)[s] &
  lat %in% unique(wind$lat)[s]
)

# for some reason adding arrows to the following plot bugs
theme_set(theme_bw(18))

qmplot(lon, lat, data = thinwind, geom = "tile", fill = spd, alpha = spd,
    legend = "bottomleft") +
  geom_leg(aes(xend = lon + delta_lon, yend = lat + delta_lat)) +
  scale_fill_gradient2("Wind Speed\nand\nDirection",
    low = "green", mid = scales::muted("green"), high = "red") +
  scale_alpha("Wind Speed\nand\nDirection", range = c(.1, .75)) +
  guides(fill = guide_legend(), alpha = guide_legend())




## kriging
############################################################
# the below examples show kriging based on undeclared packages
# to better comply with CRAN's standards, we remove it from
# executing, but leave the code as a kind of case-study
# they also require the rgdal library


library(lattice)
library(sp)
library(rgdal)

# load in and format the meuse dataset (see bivand, pebesma, and gomez-rubio)
data(meuse)
coordinates(meuse) <- c("x", "y")
proj4string(meuse) <- CRS("+init=epsg:28992")
meuse <- spTransform(meuse, CRS("+proj=longlat +datum=WGS84"))

# plot
plot(meuse)

m <- data.frame(slot(meuse, "coords"), slot(meuse, "data"))
names(m)[1:2] <- c("lon", "lat")

qmplot(lon, lat, data = m)
qmplot(lon, lat, data = m, zoom = 14)


qmplot(lon, lat, data = m, size = zinc,
  zoom = 14, source = "google", maptype = "satellite",
  alpha = I(.75), color = I("green"),
  legend = "topleft", darken = .2
) + scale_size("Zinc (ppm)")








# load in the meuse.grid dataset (looking toward kriging)
library(gstat)
data(meuse.grid)
coordinates(meuse.grid) <- c("x", "y")
proj4string(meuse.grid) <- CRS("+init=epsg:28992")
meuse.grid <- spTransform(meuse.grid, CRS("+proj=longlat +datum=WGS84"))

# plot it
plot(meuse.grid)

mg <- data.frame(slot(meuse.grid, "coords"), slot(meuse.grid, "data"))
names(mg)[1:2] <- c("lon", "lat")

qmplot(lon, lat, data = mg, shape = I(15), zoom = 14, legend = "topleft") +
  geom_point(aes(size = zinc), data = m, color = "green") +
  scale_size("Zinc (ppm)")



# interpolate at unobserved locations (i.e. at meuse.grid points)
# pre-define scale for consistency
scale <- scale_color_gradient("Predicted\nZinc (ppm)",
  low = "green", high = "red", lim = c(100, 1850)
)



# inverse distance weighting
idw <- idw(log(zinc) ~ 1, meuse, meuse.grid, idp = 2.5)
mg$idw <- exp(slot(idw, "data")$var1.pred)

qmplot(lon, lat, data = mg, shape = I(15), color = idw,
  zoom = 14, legend = "topleft", alpha = I(.75), darken = .4
) + scale



# linear regression
lin <- krige(log(zinc) ~ 1, meuse, meuse.grid, degree = 1)
mg$lin <- exp(slot(lin, "data")$var1.pred)

qmplot(lon, lat, data = mg, shape = I(15), color = lin,
  zoom = 14, legend = "topleft", alpha = I(.75), darken = .4
) + scale



# trend surface analysis
tsa <- krige(log(zinc) ~ 1, meuse, meuse.grid, degree = 2)
mg$tsa <- exp(slot(tsa, "data")$var1.pred)

qmplot(lon, lat, data = mg, shape = I(15), color = tsa,
  zoom = 14, legend = "topleft", alpha = I(.75), darken = .4
) + scale



# ordinary kriging
vgram <- variogram(log(zinc) ~ 1, meuse)   # plot(vgram)
vgramFit <- fit.variogram(vgram, vgm(1, "Exp", .2, .1))
ordKrige <- krige(log(zinc) ~ 1, meuse, meuse.grid, vgramFit)
mg$ordKrige <- exp(slot(ordKrige, "data")$var1.pred)

qmplot(lon, lat, data = mg, shape = I(15), color = ordKrige,
  zoom = 14, legend = "topleft", alpha = I(.75), darken = .4
) + scale



# universal kriging
vgram <- variogram(log(zinc) ~ 1, meuse) # plot(vgram)
vgramFit <- fit.variogram(vgram, vgm(1, "Exp", .2, .1))
univKrige <- krige(log(zinc) ~ sqrt(dist), meuse, meuse.grid, vgramFit)
mg$univKrige <- exp(slot(univKrige, "data")$var1.pred)

qmplot(lon, lat, data = mg, shape = I(15), color = univKrige,
  zoom = 14, legend = "topleft", alpha = I(.75), darken = .4
) + scale



# adding observed data layer
qmplot(lon, lat, data = mg, shape = I(15), color = univKrige,
  zoom = 14, legend = "topleft", alpha = I(.75), darken = .4
) +
  geom_point(
    aes(x = lon, y = lat, size = zinc),
    data = m, shape = 1, color = "black"
  ) +
  scale +
  scale_size("Observed\nLog Zinc")







## End(Not run) # end dontrun

dkahle/ggmap documentation built on March 3, 2024, 8:19 a.m.