# install.packages("leaflet")
library(leaflet)

# Zakladni pouziti v krocich
# 1) vytvoreni widgetu (vizualni interaktivni prvek, slouzici k otevirani a ovladani ruznych programu a programovych skupin
# 2) priani vrstev pomoci prislusnych funkci pr.: addTiles, addMarkers, addPolygons,...
# 3) zobrazeni widgetu (vcetne vrstev)

m <- leaflet() %>%
  addTiles() %>%                    
  addMarkers(lng = 174.768, lat = -36.852, popup = "The birthplace of R")  # pridame bod/marker 
m 

# lze pouzit i klasictejsi strukturovany zapis
m <- leaflet()
m <- addTiles(m)
m <- addMarkers(m, lng = 174.768, lat = -36.852, popup = "The birthplace of R")
m

# note: moznost napojeni leaflet s dazabazemi napr. maps
# install.packages("maps")
library(maps)
mapStates = map("state", fill = TRUE, plot = FALSE)
leaflet(data = mapStates) %>% addTiles() %>%
  addPolygons(fillColor = topo.colors(10, alpha = NULL), stroke = FALSE)

mapStates = map("italy", fill = TRUE, plot = FALSE)
leaflet(data = mapStates) %>% addTiles() %>%
  addPolygons(fillColor = topo.colors(10, alpha = NULL), stroke = FALSE)

# pro prehled dat v databazi maps:
help(package='maps')

###### moznosti zobrazeni v leaflet
m <- leaflet() %>% setView(lng = 16.617, lat = 49.200, zoom = 12)
m %>% addTiles()
# setView nastavi souradnice na ktere se checme zamerit

# funkce addProviderTiles(providers$_________) nastavi v podstate typ mapy
# prehled: http://leaflet-extras.github.io/leaflet-providers/preview/index.html
# priklad pouziti
m %>% addProviderTiles(providers$CartoDB.Positron)
m %>% addProviderTiles(providers$Esri.WorldImagery)
m %>% addProviderTiles(providers$OpenTopoMap)
m %>% addProviderTiles(providers$CartoDB.DarkMatter)

###### zobrazeni bodu (markeru)
lat <- c(48.883, 49.200, 50.083)
long <- c(16.633, 16.617, 14.417)
df <- as.data.frame(cbind(long,lat))

# pomoci popup
leaflet(data = df) %>% addTiles() %>% 
  addMarkers(~long, ~lat, popup = c("Dolni Vestonice", "Brno", "Praha"))

# pomoci label
leaflet(data = df) %>% addTiles() %>% 
  addMarkers(~long, ~lat, label = c("Dolni Vestonice", "Brno", "Praha"))

# oboje
leaflet(data = df) %>% addTiles() %>% 
  addMarkers(~long, ~lat, popup = c("Dolni Vestonice", "Brno", "Praha"), 
             label = c("Dolni Vestonice", "Brno", "Praha"))

# zobrazeni stacionarnich bodu
leaflet()  %>% setView(lng = 16.617, lat = 49.200, zoom = 12) %>% addTiles() %>% 
  addPopups(lng = 16.617, lat = 49.200, "Brno", options = popupOptions(closeButton = FALSE))

# moznost clustrovani bodu pokud jich je na male plose hodne - fce: clusterOptions = markerClusterOptions()
# ukazka na implementovanem data.frame zemetreseni
data(quakes)
leaflet(quakes) %>% addTiles() %>% addMarkers(clusterOptions = markerClusterOptions())

# spojeni bodu useckou
leaflet() %>%  addTiles() %>% addPolylines(data = df, lng = ~long, lat = ~lat)
# spojeni jenim casti dat
leaflet() %>%  addTiles() %>% addPolylines(data = df[1:2,], lng = ~long, lat = ~lat)

leaflet() %>%  addTiles() %>% addPolylines(data = df[1:2,], lng = ~long, lat = ~lat, 
                                           color = "salmon", weight = 15, popup = "vzdušná trasa")
# weight - tloustka cary v pixeleh
# color - barva cary
# popup - obdobne jako u bodu, jen pro caru

# Heatmap v ramci leaflet - pozor, NEzobrazuje denzitu stejnym zpusobem jako ggmap
# princip neni zalozen na statisticke analyze nybrz na zpusobu zobrazeni bodu
data_vzorky <- read.table("vzorky_maps.txt",header = T, sep = "\t")
str(data_vzorky)
attach(data_vzorky)
levels(typ)

# install.packages("leaflet.extras")
library(leaflet.extras)

leaflet(data_vzorky) %>%
  addTiles() %>%
  addHeatmap( lng=~lon, lat=~lat, max = 0.6, blur = 60)

leaflet(data_vzorky) %>%
  addTiles() %>%
  addHeatmap( lng=~lon, lat=~lat, max = 0.6, blur = 30)

# dokumentace leaflet: https://rstudio.github.io/leaflet/