Download images from the streetview API

gmap_api.R

# An R Script to do some scraping

getSearchString <- function(loc,heading,pitch) {
  s <- paste('http://maps.googleapis.com/maps/api/streetview?size=640x640',
             paste('location=',loc,sep=''),
             paste('heading=',heading,sep=''),
             paste('pitch=',pitch,sep=''),
             'sensor=false',             
             sep = '&')
  s <- gsub(' ','%20',s)
}

getAllLocations <- function(lat1,lon1,lat2,lon2,N) {
  latseq <- seq(lat1,lat2,length.out=N)
  lonseq <- seq(lon1,lon2,length.out=N)  
  df <- data.frame(lat=latseq,lon=lonseq)
}

getSearchStringLatLon <- function(lat,lon,heading,pitch) {
  s <- paste('http://maps.googleapis.com/maps/api/streetview?size=640x640',
             paste('location=',lat,' ',lon,sep=''),
             paste('heading=',heading,sep=''),
             paste('pitch=',pitch,sep=''),
             'sensor=false',             
             sep = '&')
  s <- gsub(' ','%20',s)
}

downloadAllLatLon <- function(lat1,lon1,lat2,lon2,N,basestr) {
  df <- getAllLocations(lat1,lon1,lat2,lon2,N)
  pitch <- 10
  all_headings <- seq(-90,90,30)
  
  for (i in seq(N)){
    for (heading in seq(length(all_headings))) {
      s <- getSearchStringLatLon(df$lat[i],df$lon[i],all_headings[heading],pitch)
      download.file(s,paste(basestr,
                            sprintf('%03d',i),
                            sprintf('%03d',heading),
                            '.jpg',
                            sep='_'))
    }
  }
}
  
# test download all
lat1 <- 41.876862
lon1 <- -87.632736
lat2 <- 41.876879
lon2 <- -87.631515

downloadAllLatLon(lat1,lon1,lat2,lon2,3,'chicagotest')

# do a test
for (i in seq(0,360,10)) {
  s <- getSearchString('1737 Cambridge St., Cambridge MA',i,10)
  fname <- paste('foo',sprintf('%03d',i),'.jpg',sep='')
  download.file(s,fname)
}