Block_Shapefile.R

#Set Working Directory and Options
setwd("~/Dropbox/Blocks")
options(scipen=999)

#Load Packages
packages <- c("R.utils","data.table","RCurl","bit64","maptools","rgdal","rgeos")
for (package in packages){
  if(paste(package) %in% rownames(installed.packages()) == FALSE) {install.packages(paste(package))}
  library(paste(package),character.only=TRUE)
}


##################
# Download blocks
##################


FIPS_USPS <- fread("FIPS_USPS_CODE.csv") #Lookup from: https://www.census.gov/geo/reference/ansi_statetables.html

#List of the states
state_list <- FIPS_USPS[,FIPS] #Get state numbers

#Download the block shapefiles - this is a bit crap in R; might be better to use an FTP client
for (i in 1:length(state_list)){
  
  URL_file <- paste0("tl_2015_",state_list[i],"_tabblock10")
  URL <- paste0("ftp://ftp2.census.gov/geo/tiger/TIGER2015/TABBLOCK/",URL_file,".zip")
  download.file(URL,paste0(URL_file,".zip")) #Download
  unzip (paste0(URL_file,".zip"), exdir = ".") #Unzip
  file.remove(paste0(URL_file,".zip"))
}

#Create a US Block File from the states
#List files
files <- list.files(pattern=".shp$", recursive=TRUE,full.names=TRUE) #Generate list of shapefiles
system(paste0("ogr2ogr blocks.shp"," ",files[1]," -simplify 0.00009 -overwrite")) #Simplify and copy

#Loop to merge shapefiles / simplify
for (i in 2:length(files)){
  system(paste0("ogr2ogr tmp.shp"," ",files[i]," -simplify 0.00009 -overwrite")) #Simplify and copy
  system("ogr2ogr -f 'ESRI Shapefile' -update -append blocks.shp tmp.shp") #Merge blocks
  file.remove(list.files(pattern="tmp"))
  print(i)
}

#Remove unwanted columns

system("ogrinfo blocks.shp -sql 'ALTER TABLE blocks DROP COLUMN STATEFP10'")
system("ogrinfo blocks.shp -sql 'ALTER TABLE blocks DROP COLUMN COUNTYFP10'")
system("ogrinfo blocks.shp -sql 'ALTER TABLE blocks DROP COLUMN TRACTCE10'")
system("ogrinfo blocks.shp -sql 'ALTER TABLE blocks DROP COLUMN BLOCKCE10'")
system("ogrinfo blocks.shp -sql 'ALTER TABLE blocks DROP COLUMN NAME10'")
system("ogrinfo blocks.shp -sql 'ALTER TABLE blocks DROP COLUMN MTFCC10'")
system("ogrinfo blocks.shp -sql 'ALTER TABLE blocks DROP COLUMN UR10'")
system("ogrinfo blocks.shp -sql 'ALTER TABLE blocks DROP COLUMN UACE10'")
system("ogrinfo blocks.shp -sql 'ALTER TABLE blocks DROP COLUMN UATYPE'")
system("ogrinfo blocks.shp -sql 'ALTER TABLE blocks DROP COLUMN FUNCSTAT10'")
system("ogrinfo blocks.shp -sql 'ALTER TABLE blocks DROP COLUMN INTPTLAT10'")