library(gplots)
library(rjson)
library(RgoogleMaps)
library(RColorBrewer)
tmp = fromJSON(file ="http://data.baltimorecity.gov/api/views/aivj-4x23/rows.json")
m = lapply(tmp$data,function(x){c(x[[22]][[3]][1],x[[22]][[2]][1])})
m = matrix(unlist(m),ncol=2,byrow=T)
gunViolations=apply(m,2,as.numeric)

MyMap = GetMap.bbox(lonR = gunViolations[,1],latR=gunViolations[,2],destfile="~/Desktop/baltimore.png")

##bitmap(file="baltimoreGunViolations.png",res=600,height=4,width=4)
pdf("baltimoreGunViolations.pdf",width=5,height=5)
PlotOnStaticMap(MyMap,lat=gunViolations[,2],lon=gunViolations[,2],pch=19,cex=0)

newxy = LatLon2XY.centered(MyMap, gunViolations[,2],gunViolations[,1],zoom=MyMap$zoom)
points(newxy$newX,newxy$newY,bg="red",cex=0.35,pch=21)

### I got these locations from http://itouchmap.com/latlong.html
locs=rbind(c(39.364273,-76.672748),
  c(39.357503,-76.621054),
  c(39.354427,-76.638383),
  c(39.341543,-76.615277),
  c(39.330581,-76.61961),
  c(39.333371,-76.632607),
  c(39.297512,-76.592889))

locs=LatLon2XY.centered(MyMap,locs[,1],locs[,2],zoom=MyMap$zoom)
locNames <-  c("MountWashington","Homeland","RolandPark","Guilford","Homewood","Hampden","JHMI")

for(i in seq(along=locNames)){
  text(locs$newX[i],locs$newY[i],bquote(bold(.(locNames[i]))),cex=0.65,col="darkblue")
}
dev.off()