I want to plot a simple world map with gpplot, but when I do, antarctica gets cut off, because the coordinates don't wrap around, so the path goes back across the whole map, instead of going out the edges. For example:
world_data <- map_data("world")
ggplot() + scale_y_continuous(limits=c(-90,90), expand=c(0,0)) +
scale_x_continuous(expand=c(0,0)) +
theme(axis.ticks=element_blank(), axis.title=element_blank(),
axis.text=element_blank()) +
geom_polygon(data=world_data, mapping=aes(x=long, y=lat, group=group), fill='grey')
Produces:
But the sounthern most part of antarctica is missing - it should look like this:
Is there a simple way to fix this problem?
The wrld_simpl data file from the maptools package seems to have more reliable map data, including data for Antarctica that goes all the way to -90 degrees latitude. For example:
library(maptools)
data(wrld_simpl)
ggplot() +
geom_polygon(data=wrld_simpl,
aes(x=long, y=lat, group=group), fill='grey20') +
coord_cartesian(xlim=c(-180,180), ylim=c(-90,90)) +
scale_x_continuous(breaks=seq(-180,180,20)) +
scale_y_continuous(breaks=seq(-90,90,10))
Hi #eipi10: your code does not work well when setting coord_map(). Antarctica looks weird.
ggplot() +
geom_polygon(data=fortify(wrld_simpl),
aes(x=long, y=lat, group=group), fill='grey20') +
coord_map(xlim=c(-180, 180), ylim=c(-90, 90)) +
scale_x_continuous(breaks=seq(-180, 180, 20)) +
scale_y_continuous(breaks=seq(-90, 90, 10))
Actually I found that most built-in world maps in R packages such as mapdata, maptools and maps don't work correctly with coord_map(). Highly appreciate it if someone can figure it out.
Related
How can I plot GPS trajectory over road and zoom on that road?
Can someone please take a point (40.74640013950355, -73.98755303328286, in Manhattan) and plot it over the corresponding road network [may be a grid 600ft by 600ft]. Please edit the code below to illustrate -
lat <- 40.74640013950355
long <- -73.98755303328286
tbl <- tibble(lat, long)
ggplot(data = tbl,
aes(x = lat,
y = long)) +
geom_point()
Once I know how to plot the road and I can overlay my trajectory data by modifying tbl above.
Thanks
There is no big difficulty to achieve such plot, starting from the example given in tigris library:
library(tigris)
library(ggplot2)
library(ggthemes)
roads <- roads("Maine", "031")
gg <- ggplot() + geom_sf(data = roads, color="black", fill="white", size=0.25) + theme_map()
lat <- 43.5; long <- -70.6; bbox = 0.02
bbox_gg = coord_sf(xlim=c(long-bbox/2, long+bbox/2), ylim=c(lat-bbox/2, lat+bbox/2))
gg + geom_point(data=data.frame(lat, long), aes(x=long, y=lat), size=4, color="red") + bbox_gg
What is done here is just adding a geom_point() aesthetic on top of the geom_sf() layer. We can use a kind of bounding box coordinate limit to adjust the zoom
EDIT
If you need some road names on your map, you can add this to the plot:
geom_sf_label(data=subset(roads, roads$RTTYP!="M"), aes(label=FULLNAME))
here I use subset to avoid plotting all little road names. Eventually, you might want to find a way to zoom/subset your data before plotting, because it's gonna be too long to do it like this.
I downloaded the GeoJSON file from this link : https://public.opendatasoft.com/explore/dataset/contours-iris/export/
and I plot it, but I have an interference polygone
interference_polygon_picture
but on the web site, it shows the polygons and there is not this polygone :
https://public.opendatasoft.com/explore/dataset/contours-iris/map/?q=gers&location=13,43.65999,0.5815&basemap=jawg.streets
I have ever tried to map with another file in shx from another website, and I have the same problem near the same town (Auch)
How can I delete it? Is it a problem with my R code?
Thank you for your help
iris.poly2 <- readOGR(dsn="contours-iris.geojson", "OGRGeoJSON")
ggplot() +
geom_polygon(data=iris.poly2, aes(x=long, y=lat, group=id), color="grey", size=0.1) +
coord_map(xlim=c(0.4627843, 0.6773605),
ylim=c(43.58996 , 43.72575) )
Solved with replacing group=id by group=group
ggplot() +
geom_polygon(data=iris.poly2, aes(x=long, y=lat, group=group), color="grey", size=0.1) +
coord_map(xlim=c(0.4627843, 0.6773605),
ylim=c(43.58996 , 43.72575) )
group=id created a link between 3 polygons => the interference polygon
I found the following example for plotting a map with Canadian cities: https://plot.ly/ggplot2/maps/
The R code reads as follows:
library(plotly)
Sys.setenv("plotly_username"="XXXXXXXXX")
Sys.setenv("plotly_api_key"="YYYYYYYYY")
data(canada.cities, package="maps")
viz <- ggplot(canada.cities, aes(long, lat)) +
borders(regions="canada", name="borders") +
coord_equal() +
geom_point(aes(text=name, size=pop), colour="red", alpha=1/2, name="cities")
ggplotly()
I would like to modify the example in a way that the name of the city shows up when hovering with the mouse over the relevant point in the map.
How would I need to modify the above example to implement this?
This ended up being a bug, so thanks for reporting! I just issued a fix here so try re-installing (devtools::install_github("ropensci/plotly")) and re-running:
data(canada.cities, package="maps")
viz <- ggplot(canada.cities, aes(long, lat)) +
borders(regions="canada", name="borders") +
coord_equal() +
geom_point(aes(text=name, size=pop), colour="red", alpha=1/2, name="cities")
ggplotly()
Here's a screenshot, with the custom hover text!
As you can see below, there is a weird displaying problem on the maps I made using ggplots. The same problem seems to happen with any projection.
Here is the code:
Only the packages maps and ggplot2 are needed
mapWorld <- borders("world", colour="gray50", fill="black")
ggplot() + mapWorld +
coord_map("mercator") +
ylim(-90,90)
Apparently the problem is caused by the polygons that cross the 0 coordinate, the place in which the world merges. R dont knows how to close those polygons and projects them all around the world.
This method recreates the polygons and prevents them from crossing the 0 coordinate (xlim and ylim). It works with any kind of projection.
require(ggplot2)
require(PBSmapping)
require(data.table)
mapWorld <- map_data("world")
setnames(mapWorld, c("X","Y","PID","POS","region","subregion"))
worldmap = clipPolys(mapWorld, xlim=xlim,ylim=ylim, keepExtra=TRUE)
ggplot() + geom_polygon(data = mapWorld, aes(X,Y,group=PID))
why you need to use?
ggplot() + mapWorld +
coord_map("mercator") +
ylim(-90,90)
if u use just
ggplot() + mapWorld
It works perfectly
I'm struggling to overlay neighborhood boundaries on a google map. I'm trying to follow this code. My version is below. Do you see anything obviously wrong?
#I set the working directory just before this...
chicago = readOGR(dsn=".", layer="CommAreas")
overlay <- spTransform(chicago,CRS("+proj=longlat +datum=WGS84"))
overlay <- fortify(overlay)
location <- unlist(geocode('4135 S Morgan St, Chicago, IL 60609'))+c(0,.02)
ggmap(get_map(location=location,zoom = 10, maptype = "terrain", source = "google",col="bw")) +
geom_polygon(aes(x=long, y=lat, group=group), data=overlay, alpha=0)+
geom_path(color="red")
Any insight would be much appreciated. Thanks for your help and patience.
This worked for me:
library(rgdal)
library(ggmap)
# download shapefile from:
# https://data.cityofchicago.org/api/geospatial/cauq-8yn6?method=export&format=Shapefile
# setwd accordingly
overlay <- readOGR(".", "CommAreas")
overlay <- spTransform(overlay, CRS("+proj=longlat +datum=WGS84"))
overlay <- fortify(overlay, region="COMMUNITY") # it works w/o this, but I figure you eventually want community names
location <- unlist(geocode('4135 S Morgan St, Chicago, IL 60609'))+c(0,.02)
gmap <- get_map(location=location, zoom = 10, maptype = "terrain", source = "google", col="bw")
gg <- ggmap(gmap)
gg <- gg + geom_polygon(data=overlay, aes(x=long, y=lat, group=group), color="red", alpha=0)
gg <- gg + coord_map()
gg <- gg + theme_bw()
gg
You might want to restart your R session in the event there's anything in the environment causing issues, but you can set the line color and alpha 0 fill in the geom_polygon call (like I did).
You can also do:
gg <- gg + geom_map(map=overlay, data=overlay,
aes(map_id=id, x=long, y=lat, group=group), color="red", alpha=0)
instead of the geom_polygon which gives you the ability to draw a map and perform aesthetic mappings in one call vs two (if you're coloring based on other values).