Mapping Satellite Data with RGoogle Maps

Dataset Colleted By: Jing Yuan, Yu Zheng, Xing Xie, Guang Sun, 2011

• Load the R mapping module
• Load the data
• Name the columns
• Review the data structure

library(RgoogleMaps)
setwd("F:/_rdev/telematics/01")
dat <- read.table("366.txt",header=FALSE,sep=",")
colnames(dat) <- c("ID","DateTime","Longitude","Latitude")
str(dat)

## 'data.frame':    99494 obs. of  4 variables:
##  $ ID       : int  366 366 366 366 366 366 366 366 366 366 ...
##  $ DateTime : Factor w/ 95475 levels "2008-02-02 13:30:48",..: 1 2 3 4 5 6 7 8 9 10 ...
##  $ Longitude: num  116 116 116 116 116 ...
##  $ Latitude : num  39.9 39.9 39.9 39.9 39.9 ...

• Prepare mapping parameters
• Place lat/long coordinates in vectors

center = c(mean(dat$Latitude), mean(dat$Longitude));
zoom <- 15
markers = paste0("&markers=color:Red|label:T|dat$Latitude,dat$Longitude")
# collect coordinates
vlat <- c(); vlat <- dat$Latitude
vlon <- c(); vlon <- dat$Longitude
# Map the coordinates
Taxi366Map <- GetMap(center=center,
                    zoom=zoom,
                    markers=paste0("&markers=color:green|label:T|","39.90732,116.4535"),
                    destfile="Taxi336.png",
                    maptype="hybrid")
tmp <- PlotOnStaticMap(Taxi366Map,
                       lat=vlat,lon=vlon,
                       destfile="Taxi336.png",
                       cex=0.5,pch=20,col='green',add=FALSE)

Basemap: Hybrid Satellite & Roadways

• Map additional Taxi

dat <- read.table("1131.txt",header=FALSE,sep=",")
colnames(dat) <- c("ID","DateTime","Longitude","Latitude")
center = c(mean(dat$Latitude), mean(dat$Longitude));
zoom <- 15
markers = paste0("&markers=color:Red|label:T|",c(mean(dat$Latitude), mean(dat$Longitude)))
# collect coordinates
vlat <- c(); vlat <- dat$Latitude
vlon <- c(); vlon <- dat$Longitude
# Map the coordinates
Taxi1131Map <- GetMap(center=center,
                    zoom=zoom,
                    markers=markers,
                    destfile="Taxi1131.png",
                    maptype="terrain")
tmp <- PlotOnStaticMap(Taxi1131Map,
                       lat=vlat,lon=vlon,
                       destfile="Taxi1131.png",
                       cex=0.5,pch=20,col='blue',add=FALSE)

Basemap: Terrain

dat <- read.table("1277.txt",header=FALSE,sep=",")
colnames(dat) <- c("ID","DateTime","Longitude","Latitude")
center = c(mean(dat$Latitude), mean(dat$Longitude));
zoom <- 10
markers = paste0("&markers=color:Red|label:T|",c(mean(dat$Latitude), mean(dat$Longitude)))
# collect coordinates
vlat <- c(); vlat <- dat$Latitude
vlon <- c(); vlon <- dat$Longitude
# Map the coordinates
Taxi1277Map <- GetMap(center=center,
                    zoom=zoom,
                    markers=markers,
                    destfile="Taxi1277.png",
                    maptype="roadmap")
tmp <- PlotOnStaticMap(Taxi1277Map,
                       lat=vlat,lon=vlon,
                       destfile="Taxi1277.png",
                       cex=0.25,pch=20,col='red',add=FALSE)

Basemap: Roadmap