I would like to create a map that is not perfectly square but rectangular and is the size I dictate.
require(ggmap)
tenmile <- get_map(location = c(lon = -122.486328, lat = 48.862813),
color = "color",
source = "google",
maptype = "roadmap",
zoom = 12)
tenmile.map <- ggmap(tenmile,
extent = "device",
ylab = "Latitude",
xlab = "Longitude")+ggtitle("GEOMean for Data from Oct 2013-Nov 2014")
tenmile.map + geom_point(data=pp, aes(x=lon, y=lat, size=geomean), color="red", alpha=0.5) +
geom_text(data=pp, aes(x=lon, y=lat, label = site), size=3, vjust = 1.25, hjust = -0.1)
I would post pictures of what I get and what I want but I do not have enough reputation points to post images. =-(
Sandy Muspratt's answer produces a rectangular map, but it gets stretched. To get an unstretched map, ratio must be adjusted to the ratio between spacing of parallels and meridians at the place of the map. That is:
ratio = 1/cos(latitude)
If latitude is given in degrees, that becomes:
ratio = 1/cos(pi*latitude/180)
I give here an example using a map of Barcelona (Barcelona makes a good example to check for stretching because most of our streets form an square grid and deformation becomes easily noticeable).
library(ggmap) library(mapproj) mapbcn <- get_map(location =
'Barcelona, Catalonia', zoom = 13)
# square map (default) ggmap(mapbcn)
# map cropped by latitude
ggmap(mapbcn) +
coord_fixed(ylim=c(41.36,41.41),
ratio=1/cos(pi*41.39/180))
# map cropped by longitude
ggmap(mapbcn) +
coord_fixed(xlim=c(2.14, 2.18),
ratio=1/cos(pi*41.39/180))
It must be noted that this way coordinates keep working for the whole map (for example to add points to the map) if the area of the map is small enough not to take in account Earth's curvature - that is, to assume that meridians are parallel in the area shown by the map. It may be inaccurate in a map spanning some hundreds of kilometres and very wrong in a continent-scale map.
If you want to keep the original limits of the bounding box but simply to change its shape, you can adjust the aspect ratio. If you want to change the limits of the bounding box, then obtain the map as before but set its limits using coord_fixed() (or coord_cartesian()). Or you can adjust both the aspect ratio and the limits of the bounding box.
tenmile <- get_map(location = c(lon = -122.486328, lat = 48.862813),
color = "color",
source = "google",
maptype = "roadmap",
zoom = 12)
tenmile.map <- ggmap(tenmile,
ylab = "Latitude",
xlab = "Longitude")+ggtitle("GEOMean for Data from Oct 2013-Nov 2014") +
coord_fixed(xlim = c(-122.55, -122.40), ratio = 2/1)
Related
I'm trying to add a 20km scale bar to my map but every solution I've tried either adds the scale bar off screen (you can only see the bottom of the "km") or doesn't add it at all.
The closest I've come has been using scalebar(), which adds a scale bar off screen but doesn't allow me to move it to be fully visible. I've also tried making a bar from scratch with geom_line etc but that did not plot at all.
Here is a reproducible map without an attempt to make a scale bar and a small set of coordinates
library(ggmap)
library(ggsn)
wd <- getwd()
Latitude <- c(34.1365, 34.14435, 34.05111, 34.17605)
Longitude <- c(-117.92391, -117.85036, -118.31712, -118.31712)
graphingdata <- cbind.data.frame(Latitude,Longitude)
# compute the bounding box
bc_bbox <- make_bbox(lat = as.numeric(graphingdata$Latitude), lon = as.numeric(graphingdata$Longitude))
bc_bbox
# grab the map from google
site_map <- get_stamenmap(bc_bbox, zoom = 10, maptype = "terrain")
#create and save the map
png(file=paste0(wd,"stack-ex-graph.png"))
map <- ggmap(site_map, legend = "bottom") +
geom_point(data = graphingdata, aes(x = as.numeric(Longitude),
y = as.numeric(Latitude)), color = "red", size = 2) +
ggtitle(paste0("This is the map title"),
subtitle = paste0("This is the subtitle"))
print(map)
dev.off()
I ended up being able to use the anchor argument to shift the location of the scale bar. Because of the scope of the project I made the anchor and bounding of the map flexible.
#Create the data frame
Latitude <- c(34.1365, 34.14435, 34.05111, 34.17605)
Longitude <- c(-117.92391, -117.85036, -118.31712, -118.31712)
graphingdata <- cbind.data.frame(Latitude,Longitude)
#Set up bounding box
height <- max(graphingdata$Latitude) - min(graphingdata$Latitude)
width <- max(graphingdata$Longitude) - min(graphingdata$Longitude)
sac_borders <- c(bottom = min(graphingdata$Latitude) - 0.1 * height,
top = max(graphingdata$Latitude) + 0.1 * height,
left = min(graphingdata$Longitude) - 0.1 * width,
right = max(graphingdata$Longitude) + 0.1 * width)
#Get the site map
map <- get_stamenmap(sac_borders, zoom = 10, maptype = "terrain")
map <- ggmap(site_map, legend = "bottom")+
scalebar(x.min = sac_borders[[3]]-1, x.max = sac_borders[[4]]+1,y.min = sac_borders[[1]]-1, y.max = sac_borders[[2]]+1,transform = TRUE,
dist = 20,dist_unit = "km",model = "WGS84",anchor = c(x=sac_borders[[3]]+0.6,y=sac_borders[[1]]+0.25), st.size = 2, border.size = 0.5)+
geom_point(data = graphingdata, aes(x = as.numeric(Longitude),
y = as.numeric(Latitude)), color = "red", size = 2) +
ggtitle(paste0("This is the map title"),
subtitle = paste0("This is the subtitle"))
Example output map. Scale bar can be moved with the anchor argument. Zoom can be modified in get_stamenmap().
I am trying to map some data in R using ggmap. When I get the map it looks something like this.
cen <- geocode('Danmark')
center <- as.numeric(cen)
map <- get_googlemap(center = center, zoom = 6,
size = c(640, 640), scale = 2, region="dk",crop = TRUE,color="bw")
ggmap(map) #+ geom_point(aes(x = lon, y = lat, size=antal), data=df, colour="darkred")
The problem is that the island of Bornholm is located to the far east of Denmark. This makes the map very large. To increase the space usage I would like to move Bornholm to the upper right corner. Something like this
How can I do this in ggmap and still overlay data?
I have been trying to create a map of membership locations from postcodes across the UK as a project in learning R. I have achieved nearly the result I wanted, but it's proving very frustrating getting the glitches sorted. This image is my current best effort:
I still want to change:
get rid of the extraneous legend (the "0.16", "0.5" squares), which are coming from the size arg to geom_point. If I remove the size=0.16 arg the guide/legend disappears, but the geom size returns to the default too. This also happens for the "black" guide -- coming from a colour obviously -- but why?
properly clip the stat_density2d polygons, which are exhibiting undesireable behaviour when clipped (see bottom-right plot near the top)
have control over the line-width of the geom_path that includes the county boundaries: it's currently too thick (would like about 1/2 thickness shown) but all I can achieve by including 'size' values is to make the lines stupidly thick - so thick that they obscure the whole map.
The R code uses revgeocode() to find the placename closest to the centre point but I don't know how to include the annotation on the map. I would like to include it in a text-box over the North Sea (top right of UK maps), maybe with a line/arrow to the point itself. A simpler option could just be some text beneath the UK map, below the x-axis ... but I don't know how to do that. geom_rect/geom_text seem fraught in this context.
Finally, I wanted to export the map to a high-res image, but when I do that everything changes again, see:
which shows the high-res (~1700x1800px) image on the left and the Rstudio version (~660x720px) on the right. The proportions of the maps have changed and the geom_text and geom_point for the centre point are now tiny. I would be happy if the gap between the two map rows was always fairly small, too (rather than just small at high res).
Code
The basics: read list of members postcodes, join with mySociety table of postcode<>OSGB locations, convert locations to Lat/long with spTransform, calculate binhex and density layers, plot with ggmap.
The code for all this is somewhat lengthy so I have uploaded it as a Gist:
https://gist.github.com/rivimey/ee4ab39a6940c0092c35
but for reference the 'guts' of the mapping code is here:
# Get a stylised base map for the whole-of-uk maps.
map.bbox = c(left = -6.5, bottom = 49.5, right = 2, top = 58)
basemap.uk <- get_stamenmap(bb = map.bbox, zoom=calc_zoom(map.bbox), maptype="watercolor")
# Calculate the density plot - a continuous approximation.
smap.den <- stat_density2d(aes(x = lat, y = lon, fill = ..level.., alpha = ..level..),
data = membs.wgs84.df, geom = "polygon",
breaks=2/(1.5^seq(0,12,by=1)), na.rm = TRUE)
# Create a point on the map representing the centroid, and label it.
cmap.p <- geom_point(aes(x = clat, y = clon), show_guide = FALSE, data = centroid.df, alpha = 1)
cmap.t1 <- geom_text(aes(x = clat, y = clon+0.22, label = "Centre", size=0.16), data = centroid.df)
cmap.t2 <- geom_text(aes(x = clat, y = clon+0.1, label = "Centre", size=0.25), data = centroid.df)
# Create an alternative presentation, as binned hexagons, which is more true to the data.
smap.bin <- geom_hex(aes(x = lat, y = lon),
data = membs.wgs84.df, binwidth = c(0.15, 0.1), alpha = 0.7, na.rm = TRUE)
# Create a path for the county and country boundaries, to help identify map regions.
bounds <- geom_path(aes(x = long, y = lat, group = group, colour = "black"), show_guide = FALSE,
data = boundaries.subset, na.rm = TRUE)
# Create the first two actual maps: a whole-uk binned map, and a whole-uk density map.
map.bin <- ggmap(basemap.uk) + smap.bin + grad + cmap.p + cmap.t1
map.den <- ggmap(basemap.uk) + smap.den + alpha + cmap.p + cmap.t1
# Create a zoomed-in map for the south-east, to show greater detail. I would like to use this
# bbox but google maps don't respect it :(
map.lon.bbox = c(left = -1, bottom = 51, right = 1, top = 52)
# Get a google terrain map for the south-east, bbox roughly (-1.7,1.7, 50.1, 53)
basemap.lon <- get_map(location = c(0,51.8), zoom = 8, maptype="terrain", color = "bw")
# Create a new hexbin with more detail than earlier.
smap.lon.bin <- geom_hex(aes(x = lat, y = lon),
data = membs.wgs84.df, bins=26, alpha = 0.7, na.rm = TRUE)
# Noe create the last two maps: binned and density maps for London and the SE.
lonmap.bin <- ggmap(basemap.lon) + bounds + smap.lon.bin + grad + cmap.p + cmap.t2
lonmap.den <- ggmap(basemap.lon) + bounds + smap.den + alpha + cmap.p + cmap.t2
# Arrange the maps in 2x2 grid, and tell the grid code to let the first row be taller than the second.
multiplot(map.bin, lonmap.bin, map.den, lonmap.den, heights = unit( c(10,7), "null"), cols=2 )
I am creating maps using ggmap and am having trouble displaying some polygons and borders in my code. I have a map of a city that has parts of 3 counties in it. I would like to display the city along with the appropriate county lines. If I set the zoom such that all 3 counties are completely visible, then the county lines appear in the map. However, if I zoom to the portion of the city, the county lines disappear.
Example 1: County lines visible on map
tempplot <- get_map(location = c(lon = -97.37605, lat = 32.94748), zoom=9, maptype = 'roadmap')
myplot <- ggmap(tempplot) + borders ("county", colour = "red", alpha = 0.5, region = "Texas")
myplot <- myplot + geom_point(aes(x = -97.37605, y = 32.94748), color = "dodgerblue4", pch = 20, size = 9)
myplot
Image: http://imgur.com/nx3XU2I
Example 2: County lines partially visible on map
tempplot <- get_map(location = c(lon = -97.37605, lat = 32.94748), zoom=10, maptype = 'roadmap')
myplot <- ggmap(tempplot) + borders ("county", colour = "red", alpha = 0.5, region = "Texas")
myplot <- myplot + geom_point(aes(x = -97.37605, y = 32.94748), color = "dodgerblue4", pch = 20, size = 9)
myplot
Example 3: No county lines visible on map
tempplot <- get_map(location = c(lon = -97.37605, lat = 32.94748), zoom=12, maptype = 'roadmap')
myplot <- ggmap(tempplot) + borders ("county", colour = "red", alpha = 0.5, region = "Texas")
myplot <- myplot + geom_point(aes(x = -97.37605, y = 32.94748), color = "dodgerblue4", pch = 20, size = 9)
myplot
Image: http://imgur.com/dIpp6kp
The only difference between these 3 examples is the zoom on the map. I need the map to be at zoom 12 to see the additional details that I will be adding (individual homes), but when I zoom in, the county lines vanish. Any suggestions?
(Sorry about the links to the images ... I am new to the forum and don't have a 10 reputation yet!)
It appears that also the borders you get in example 1 are not 100% correct. You may check with a lower Zoom lever (eg 5).
To me it looks like there is a problem with borders that are cut off by the picture; the function then tries to connect it to an edge that is still visible. In the zoom level you provided even that is not possible, and therefore it has unexpected behaviour.
To sum up: I don't know what exactly the problem is, but maybe this short analysis helps in any way!
I have a data like this:
YEAR-STORM-DATETIME-NORTH-WEST-PRESSURE-WIND-SPEED-TRACKDATE
2011-arlene-6/28/2011 6:00-19.9-92.8-1007-30-NA-6/28/2011
2011-arlene-6/28/2011 12:00-20.3-93.1-1006-35-4-6/28/2011
2011-arlene-6/28/2011 18:00-20.7-93.5-1006-40-5-6/28/2011
so on..
I am new to R and I am plotting a density-plot over ggmap. I am also using shiny R to display them in website. The problem is the output are all non-widescreen (squared) maps. I want to have a rectangular map, like google maps provided by Openlayers or KML.
My code is :
library(ggplot2)
library(ggmap)
mydata <- read.csv("C:/R Data/Analytics/dMetrics.csv")
slice_year <- mydata[mydata$YEAR=='2009',]
map <- get_map(c(lon = -55.3632715, lat = 31.7632836), zoom = 3,
source = 'google', maptype = c("terrain"), messaging = FALSE,
color = 'color')
world <- ggmap(map) #extent = 'device'
world <- world +
stat_density2d(data = slice_year,
aes(x = WEST, y = NORTH, fill = ..level.., alpha = ..level..),
show_guide = FALSE, geom = "polygon", na.rm = TRUE) +
scale_fill_gradient(name = "Density", low = "maroon", high = "yellow",
guide = 'colorbar')
world
Please guide me through to create a widescreen resolution map, possibly a high resolution.
To save the image as widescreen, add this to the end: ggsave(file="map.pdf", width=8, height=4.5)
To open a widescreen window, add this before calling world: windows(800,450)
Edit
It looks like ggmap just doesn't support non-sqaure aspect ratios.
The documentation claims that a bounding box can be passed into the location property, but it appears to just ignore it.
scale <- 5
ratio <- 16/9
size <- c(ratio, 1) * scale
latlongCenter <- c(0, 45)
latlongBox <- c(latlongCenter - size/2, latlongCenter + size/2)
map <- get_map(location = latlongBox)
ggmap(map)
One solution would be to produce a bigger map, and then crop the piece you don't need.
But I'm still trying to figure how to produce a big, high-resolution map (the map I'm getting is 1280x1280 - that's enough for most needs, but not to print a big map). I think there's no function for that, or bots could occupy all of Google's bandwidth. A simpler solution is to get many square maps and assemble them together, but then you'll have the Google logo in all of them.
I think the only way to do that is to produce the small square maps and cut the bottom, where the logo and copyright information are. To add their logo again in the borders of the final map (cutting them differently) would give even more work...