R: put labels on a map

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R: put labels on a map

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#1 by (3 votes)

1

I would like to sketch in the map of Spain in R and add some points in certain coordinates that I have in a CSV file;

how are you:

        Aranjuez<-39.595520, -3.391830
        San Martin de la vega<- 40.225155-3.530613
        Ruta de las vegas<- 40.320294-3.205903
        Mondejar<- 40.345348-3.137145

How could I do it?

I have tried with these scripts from another forum and I can not do it.

When I run the map.unizar code I get this error:

      Error in if (lon < -180 || lon > 180) { : 
      missing value where TRUE/FALSE needed

Script: I locate my alma mater

        unizar <- geocode('Universidad de Zaragoza, Zaragoza, España')

I get a map

        map.unizar <- get_map( location = as.numeric(unizar),
                   color = "color",
                   maptype = "roadmap",
                   scale = 2,
                   zoom = 16)

I represent it

        ggmap(map.unizar)

I add points

        ggmap(map.unizar) + geom_point(aes(x = lon, y = lat),
                           data = unizar, colour = 'red',
                           size = 4)

Thanks in advance A coordial greeting

r

asked by Adrián P.L. 08.02.2018 в 18:01

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1 answer

Run the same Java thread twice [closed] pass variables in Laravel

score 3 · Accepted Answer

The problem you have is that you can not get the latitude and longitude, let's see:

address <- 'Universidad de Zaragoza, Zaragoza, España'
unizar <- geocode(address)

This in console throws the following message

Information from URL: link Warning messages: 1: In readLines (connect, warn = FALSE): can not open URL ' link ': HTTP status was '400 Bad Request' 2: In geocode (address): geocoding failed for "University of Zaragoza, Zaragoza, Spain". if accompanied by 500 Internal Server Error with using dsk, try google.

If we go directly to the link ( link ) through a browser we will get a more descriptive error:

{
   "error_message" : "Invalid request. One of the input parameters contains a non-UTF-8 string.",
   "results" : [],
   "status" : "INVALID_REQUEST"
}

That is, the address we want to search is not well coded, certain characters (probably the ñ) do not have a code utf-8 suitable. To solve this we can use enc2utf8() :

address <- enc2utf8('Universidad de Zaragoza, Zaragoza, España')

and now yes, everything that follows:

unizar <- geocode(address)
if (!any(is.na(unizar))) {
    map.unizar <- get_map( location = as.numeric(unizar),
                           color = "color",
                           maptype = "roadmap",
                           scale = 2,
                           zoom = 16)

    ggmap(map.unizar) + geom_point(aes(x = lon, y = lat),
                                   data = unizar, colour = 'red',
                                   size = 4)
} else {
    stop("No hemos podido recuperar la coordenadas")
}

I added a control to know if we could correctly recover latitude and longitude, Google can "banearte" at some point if you make many inquiries and it should be controlled.

The result:

If you want the full map of Spain you can modify the zoom level, remember also that if you already have the latitude and longitude, you do not need to call geocode() :

puntos <- data.frame(lon=c(-3.391830, -3.530613, -3.205903, -3.137145, -0.9015065),
                     lat=c(39.595520, 40.225155, 40.320294, 40.345348, 41.64206),
                     nom=c('Aranjuez', 'San Martin de la vega', 'Ruta de las vegas', 
                           'Mondejar', 'Universidad de Zaragoza, Zaragoza, España')
)

map.unizar <- get_map( location = puntos[1,-3],
                       color = "color",
                       maptype = "roadmap",
                       scale = 2,
                       zoom = 6)

ggmap(map.unizar) + geom_point(aes(x = lon, y = lat),
                               data = puntos, colour = 'red',
                               size = 2)

The Result:

If still the result does not convince you, I suggest you take a look at LeafLet , that offers you a dynamic, very configurable and attractive visualization:

library(leaflet)
library(magrittr)

puntos <- data.frame(lon=c(-3.391830, -3.530613, -3.205903, -3.137145, -0.9015065),
                     lat=c(39.595520, 40.225155, 40.320294, 40.345348, 41.64206),
                     nom=c('Aranjuez', 'San Martin de la vega', 'Ruta de las vegas', 
                           'Mondejar', 'Universidad de Zaragoza, Zaragoza, España')
)

leaflet(data = puntos) %>% 
    addTiles() %>%
    setView(lng = puntos$lon[1], lat = puntos$lat[1] , zoom = 6) %>%
    addMarkers(~lon, ~lat, popup = ~as.character(nom), label = ~as.character(nom))

Example exported to an image: