plotCurrentTraffic: To view current traffic speed of some road segments in Hong...

In bmkor/hktraffic: Display HK Traffic Data

Usage

plotCurrentTraffic(trafficURL = "http://resource.data.one.gov.hk/td/speedmap.xml")

Arguments

trafficURL

Examples

##---- Should be DIRECTLY executable !! ----
##-- ==>  Define data, use random,
##--	or do  help(data=index)  for the standard data sets.

## The function is currently defined as
function (trafficURL = "http://resource.data.one.gov.hk/td/speedmap.xml")
{
    if (require("leaflet", character.only = T, quietly = T) &
        require("XML", character.only = T, quietly = T)) {
        tdata <- XML::xmlParse(trafficURL)
        tdata <- XML::xmlToDataFrame(tdata, stringsAsFactors = F)
        tdata$ROAD_SATURATION_LEVEL <- gsub("TRAFFIC ", "", tdata$ROAD_SATURATION_LEVEL)
        tdata$ROAD_SATURATION_LEVEL <- factor(tdata$ROAD_SATURATION_LEVEL)
        tdata$CAPTURE_DATE <- strptime(tdata$CAPTURE_DATE, format = "%Y-%m-%dT%H:%M:%S")
        pale <- c("green", "yellow", "red")
        names(pale) <- c("GOOD", "AVERAGE", "BAD")
        pale <- as.vector(pale[levels(tdata$ROAD_SATURATION_LEVEL)])
        pal <- leaflet::colorFactor(pale, domain = tdata$ROAD_SATURATION_LEVEL)
        roads = getRoads()
        roads$dashPattern <- as.character(c(1, c("15, 10, 5"))[as.numeric(roads$route_type)])
        roads <- subset(roads, route %in% tdata$LINK_ID)
        roads@data <- cbind(roads@data, tdata[match(roads$route,
            data$LINK_ID), ])
        lastCaptureTime <- max(unique(tdata$CAPTURE_DATE))
        lastCaptureTime <- strftime(lastCaptureTime, format = "%H:%M, %d %b")
        leaflet(data = roads) %>% addTiles(group = "OSM (default)") %>%
            addProviderTiles(providers$Stamen.Toner, group = "Toner") %>%
            addProviderTiles(providers$Stamen.TonerLite, group = "Toner Lite") %>%
            addPolylines(color = ~pal(ROAD_SATURATION_LEVEL),
                dashArray = ~dashPattern, popup = ~paste0("average speed: ",
                  TRAFFIC_SPEED, " km/h"), label = ~route) %>%
            addLegend(position = "bottomright", pal = pal, values = ~ROAD_SATURATION_LEVEL,
                title = paste0("Road Saturation Level at ", lastCaptureTime),
                labels = ~ROAD_SATURATION_LEVEL) %>% addLayersControl(baseGroups = c("OSM (default)",
            "Toner", "Toner Lite"), options = layersControlOptions(collapsed = FALSE))
    }
  }

bmkor/hktraffic documentation built on May 12, 2019, 10:27 p.m.