Resource/Leaflet.Rmd at master · sidharthanr/Resource · GitHub

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---
title: "R Leaflet template"
author: "Raghu Sidharthan"
output:  html_document
---

[RBasic1](RBasic1),
[RBasic2](RBasic2),
[RBasic3](RBasic3),
[data.table](RDTable),
[dplyr](dplyr),
[tidyr](tidyr),
[RGIS](RGIS),
[Leaflet](Leaflet)

**Libraries to load**

```{r, message=F, warning=F}
library(rgdal)
library(leaflet)
library(htmltools)
library(data.table)
library(rgeos)
library(jsonlite)
```

```{r,results='hide',echo=-1,eval=TRUE}
setwd('C:\\Users\\sidharthanr\\Dropbox\\Resource\\Git\\Resource')
indShp <- readOGR("..\\..\\R\\GIS\\Shape\\India", "IND_adm2")
shpDT <- indShp[indShp@data$NAME_1=='Kerala',]
shpDT@data <- data.table(shpDT@data)
shpDT@data <- shpDT@data[,.(NAME_2,VARNAME_2)]
shpDT@data[,txtLbl := paste(NAME_2,'-',VARNAME_2)]
#shpDT <- gSimplify(shpDT,tol = 0.001)
row.names(shpDT@data) <- row.names(shpDT)
shpDT <- SpatialPolygonsDataFrame(shpDT,shpDT@data)
shpDT_pkd <- shpDT[shpDT@data$NAME_2 %in% c('Palakkad','Malappuram','Thrissur','Ernakulam'),]
sort( sapply(ls(),function(x){object.size(get(x))}))

```

**1. Basic template**
```{r}
leaflet() %>%
  addTiles() %>%
  addProviderTiles('Esri.WorldStreetMap',group='EsriStreet') %>%
  addProviderTiles('Esri.WorldImagery',group='EsriImagery') %>%
  addProviderTiles('CartoDB.Positron',group='CartoDB-1') %>%
  addPolygons(data=shpDT,group='Kerala',stroke=T,weight = 2,fillOpacity = 0,
               label=lapply(shpDT@data$txtLbl, function(x) HTML(x)),
               labelOptions = labelOptions(noHide = T)) %>%
  addLayersControl(
    baseGroups = c('CartoDB-1','EsriStreet','EsriImagery'),
    overlayGroups = c('Kerala'),
    options = layersControlOptions(collapsed = T)  )

```

**2. Example with GeoJSON, Markers**
```{r}
# Reading the GeoJSON File using the jsonlite package
GJFName <- '..\\..\\Data\\PKD_water_road.geojson'
GJFName_LS<- '..\\..\\Data\\PKD_water_road_LS.geojson'
GJFName_PG<- '..\\..\\Data\\PKD_water_road_PG.geojson'


pkdGJ <- readLines(GJFName, warn = FALSE) %>% paste(collapse = "\n") %>% fromJSON(simplifyVector = FALSE)
pkdGJDT <- data.table(fromJSON(GJFName)$features$properties)
pkdGJDT$geomType <- unlist(lapply(pkdGJ$features, function(feat) feat$geometry$type))

# Function to style the features for display
FeatureStyler <- function(feat) {
    t_weight = 2;t_opacity = 1;t_fillOpacity = 0;t_color = '#006d2c';t_fillColor = '#41b6c4'
    if (feat$geometry$type == 'Polygon') {
        t_fillOpacity = 0.5; t_color = '#253494'; t_fillColor = '#41b6c4'
    }
    else if (feat$geometry$type == 'LineString') t_fillOpacity = 0
    feat$properties$style <- list(weight = t_weight, opacity = t_opacity,fillOpacity = t_fillOpacity,
                color = t_color, fillColor = t_fillColor,label='sdf', labelOptions = labelOptions(noHide = T))
    feat
}
pkdGJ$features <- lapply(pkdGJ$features, FeatureStyler)

# Selector vecors to subset GeoJson Types
selectorTranspo <- (unlist(lapply(pkdGJ$features, function(feat) feat$properties$Highway)) != 'not_hway' |
    unlist(lapply(pkdGJ$features, function(feat)!is.null(feat$properties$railway))))
selectorWater <- !(selectorTranspo)

subsetGeoJSON <- function(fullGeoJSON, selectorTemplate) {
    temp <- list();    temp$type <- "FeatureCollection";    temp$features <- fullGeoJSON$features[selectorTemplate]
}
pkdGJ_water    <- subsetGeoJSON(pkdGJ,selectorWater)

pkdGJ_transpo    <- readOGR(GJFName_LS, "OGRGeoJSON")
pkdGJ_transpo <- pkdGJ_transpo[pkdGJ_transpo@data$Highway!='not_hway',]
pkdGJ_transpo@data <- data.table(pkdGJ_transpo@data)[,.(Name,Highway)]
pkdGJ_transpo@data[is.null(Name),Name:='Unknown']

  pkdTranCen = data.table(data.frame(gCentroid(pkdGJ_transpo,byid=TRUE)))
  pkdTranCen[,Name:=pkdGJ_transpo$Name]
  pkdTranCen[,Highway:=pkdGJ_transpo$Highway]
  pkdTranCen <- pkdTranCen[Name!='null',]
  pkdTranCen <- pkdTranCen[!duplicated(Name) & Highway %in% c('trunk'),]

leaflet() %>%  addTiles() %>%
  addProviderTiles('Esri.WorldStreetMap',group='EsriStreet') %>%
  addProviderTiles('CartoDB.Positron',group='CartoDB-1') %>%
  addPolygons(data=shpDT_pkd,group='Cenral Kerala',stroke=T,weight = 2,fillOpacity = 0,
               label=lapply(shpDT_pkd@data$txtLbl, function(x) HTML(x)),
               labelOptions = labelOptions(noHide = T)) %>%
  addGeoJSON(pkdGJ_water, group = 'Water') %>%
  addMarkers(lng=76.639003, lat=10.800471, popup="Palakkad Jn.",group='Landmarks') %>%
  addPolylines(data=pkdGJ_transpo,group='transpo', weight = 2, color='#c51b8a') %>%
    addCircleMarkers(lng = pkdTranCen$x, lat = pkdTranCen$y,
                     label = as.character((pkdTranCen$Name)),group='transpo',opacity=0,radius = 1,
                     labelOptions = lapply(1:nrow(pkdTranCen), function(x) {
                       labelOptions(opacity=1, noHide = T,textOnly = TRUE,textsize='10px',
                                    direction = 'auto', offset=c(20,-15))
                     })) %>%

  setView(lng=76.64, lat=10.8,zoom = 10) %>%
  addLayersControl(
    baseGroups = c('CartoDB-1','EsriStreet'),
    overlayGroups = c('Cenral Kerala','Water','Landmarks','transpo'),
    options = layersControlOptions(collapsed = T) )
```

**3. Save to HTML**
```{r,eval=F}
library(htmlwidgets)
saveWidget(mm, file = 'SERPM_MAZ_n_TAZ.html', selfcontained = F)
```