Tag Archives: leaflet

Trip

Sharing pictures from holidays in the Canadian Rockies (with R)

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My kids have a very popular blog (at least among their grandmothers) where they frequently post pictures from everyday’s life (since they live 5000km from them), as well as pictures taken from holidays. This afternoon, I tried to used the popupImage function from the leaflet package to post pictures, on a map (to explain where we spent our holiday this summer). This post is just to keep tracks of that code.

First, we need to load the appropriate R packages

library(leaflet)
library(mapview)

Then, we take a picture, and we locate it, for instance Mirror Lake (on the trail to Lake Agnes). Since leaflet uses openstreetmap, I recommend to use it also for location (and not google maps… coordinates can be slightly different)

df=data.frame(lat =51.41603, long=-116.23946,
nom = "Miror Lake",photo="http://freakonometrics.free.fr/jaspeR/_DSC5967.jpg")

I guess you can also use the metadata if you take pictures with a cell phone, and you add the location… but I am (very) old fashioned, and still use a camera to take pictures. Then you can add a dozen pictures

df=rbind(df, data.frame(lat =51.4164, long=-116.2442,
nom = "Lake Agnes",photo="http://freakonometrics.free.fr/jaspeR/_DSC6003.jpg"))
df=rbind(df, data.frame(lat =51.3215642,long=-116.193718,
nom="Moraine Lake",photo="http://freakonometrics.free.fr/jaspeR/_DSC5957.jpg"))

From that dataframe, we need two kinds of information: the location, and the url of the picture,

data_df=df[,c("lat","long")]
images = as.character(df$photo)

Then we can create the leaflet map (sorry for typos, but wordpress converts the > symbol into some “>” characters… which makes R pipe operator hard to read)

m = leaflet(data_df) %>%
  addTiles() %>%
  addCircleMarkers(
    fillOpacity = 0.8, radius = 5,
    lng = ~long, lat =~lat, 
    popup = popupImage(images)
  )

and export it (in a nice html file)

library(htmlwidgets)
saveWidget(m, file="jaspR.html")

CAS in R, Databases, Maps

A quelle distance d’une banque habite-t-on ?

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Dans le cadre du projet de R de la formation en Data Science pour l’Actuariat, je vais continuer à mettre en ligne des morceaux de codes qui peuvent être utiles, dans un contexte spatial. Le dernier billet, sur cartographier le vote pour le Brexit, avait été repris (et bien amélioré) sur le site des voisins de rgeomatic. Aujourd’hui, je vais m’inspirer du travail d’Etienne Flichy qui mixe répartition de la population sur le territoire, et localisation des agences bancaires.

On parle des banques ici, mais si on a une base avec les coiffeurs, les boulangeries, etc, on peut faire la même chose ! (autant dire qu’on va pouvoir s’amuser quand la base sirene sera rendue ouverte – dans les semaines à venir). On va supposer que l’on a une base avec toutes les banques géocodées. Bon, pour l’exercice, on va utiliser la localisation des agences bancaires, en utilisant les données de cbanque.com. C’est assez facile d’aller scraper le site, quand on regarde la façon dont sont faites les pages, e.g. http://cbanque.com/pratique/agences/credit-cooperatif/35/. Là on récupère les adresses (postales) et on peut utiliser https://adresse.data.gouv.fr/csv/ (ou différents outils) pour géolocaliser les adresses.

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Maps

Playing with Leaflet (and Radar locations)

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Yesterday, my friend Fleur did show me some interesting features of the leaflet package, in R.

library(leaflet)

In order to illustrate, consider locations of (fixed) radars, in several European countries. To get the data, use

download.file("http://carte-gps-gratuite.fr/radars/zones-de-danger-destinator.zip","radar.zip")
unzip("radar.zip")
 
 ext_radar=function(nf){
radar=read.table(file=paste("destinator/",nf,sep=""), sep = ",", header = FALSE, stringsAsFactors = FALSE)
 radar$type <- sapply(radar$V3, function(x) {z=as.numeric(unlist(strsplit(x, " ")[[1]])); return(z[!is.na(z)])})
  radar <- radar[,c(1,2,4)]
  names(radar) <- c("lon", "lat", "type")
  return(radar)}
 
L=list.files("./destinator/")
nl=nchar(L)
id=which(substr(L,4,8)=="Radar" & substr(L,nl-2,nl)=="csv")
 
radar_E=NULL
for(i in id) radar_E=rbind(radar_E,ext_radar(L[i]))

(to be honest, if you run that code, you will get several countries, but not France… but if you want to add it, you should be able to do so…). The first tool is based on popups. If you click on a point on the map, you get some information, such as the speed limit where you can find a radar. To get a nice pictogram, use

fileUrl <- "http://evadeo.typepad.fr/.a/6a00d8341c87ef53ef01310f9238e6970c-800wi"
download.file(fileUrl,"radar.png", mode = 'wb')
RadarICON <- makeIcon(  iconUrl = fileUrl,   iconWidth = 20, iconHeight = 20)

And then, use to following code get a dynamic map, mentionning the variable that should be used for the popup

m <- leaflet(data = radar_E) 
m <- m %>% addTiles() 
m <- m %>% addMarkers(~lon, ~lat, icon = RadarICON, popup = ~as.character(type))
m

Because the picture is a bit heavy, with almost 20K points, let us focus only on France,

Continue reading Playing with Leaflet (and Radar locations) →